Revisiting "Imaging"

[Mr. Widget]

On a recent thread: http://www.audioheritage.org/vbulletin/showthread.php?41068-Anyone-tried-the-Troels-Gravesen-L112-upgraded-crossovers one of several divergent topics from the original topic dove into the discussion of imaging.

Like everything else in this hobby, there are many opinions on how to get great imaging. That said, I'm not even sure we are all taking about the same thing when we discuss imaging.

I define imaging as the the speaker's soundstage. In my opinion for there to be imaging you typically do need to have a setup where you can sit at an equidistant vertex of a triangle. I realize for many this is simply not possible. While it is still possible to have a very satisfying musical experience I don't think outstanding imaging will be possible.

To me a speaker with outstanding imaging will create a holographic soundstage when playing back recordings that are recorded in a manner where there is the appropriate sonic information. If the recording has been recorded in a manner that preserves spatial details, you may hear sounds apparently coming from deep behind the plane of the speakers as well as infront of them. A vocalist may be so locked into the center there appears to be narrow window from which they are singing, and sounds may appear far to the left or right of the speakers and sometimes sounds or instruments even seem to be behind you. I've heard "audiophiles" refer to this as having speakers that "disappear".

Most speakers will throw some form of image and create a soundstage that is likely not that far off from what we are likely to hear at a typical live musical performance. That said, speakers with outstanding imaging create an immersive soundstage that can be quite compelling. This sort of imaging occasionally occurs in live music, but not typically.

I recently moved and am currently using my 1400 Array speakers as my primary speakers and am simply blown away by their imaging. Of the JBL speakers I've heard a lot over the years these are hands down the best at creating this holographic illusion. The M2s are supposed to also do this and likely do, but I have not spent that much time with them and didn't hear them with music that was recorded to create such an immersive soundstage. Also I believe associated electronics and sources also have a pronounced affect on the soundstage/imaging of a system. Perhaps when I've heard the M2s the electronics didn't allow the speakers to perform at their best.

As I write this I'm listening to Deep Forest - Boheme. There are sounds from nature, birds etc. that are far off to the left, right, and even behind me. It sounds like a Dolby Atmos system... but it is only a two channel system. The music is spinning off a hard drive in a Mac Mini, through a Bryston BDA 2, controlled by my Mark Levinson 326S and powered by an old GAS Son of Ampzilla biased to stay in class A until loud peaks. Is this the end all of all time? No. I still prefer the Everests with unlimited dynamics and a bit punchier sound all around, but like most speakers even those amazing Everests can not compete with some of the best mini monitors or these 1400 Arrays when it comes to imaging.


Widget

[sguttag]

Without a doubt, the M2s had the best imaging I've ever heard from any pair of speakers, anywhere at any time. It was spooky how good they are. Close your eyes and if it was recorded to provide a sound stage, it will be laid right out before you. We built five of them and they ALL did it (pick any two). Furthermore, you don't have to sit equidistant with them. There is a lot of latitude with where you are sitting/standing.

Prior to the M2s, the L250s were my favorites for imaging but I think they have been bested.

I don't think it is the fancy electronics that allows the M2s to do this either. I think it is that waveguide combined with clearly hand selected D2 drivers (there are two grades of the D2...the ones for the M2 and the ones for commercial PA systems). I think that because they get such a good match between systems, they get them to image very well. FWIW, my electronics are not even Harmon but QSC (QSYS) and I've listened to them with both Class-D and Class-H amplification (I preferred Class-H). Other than the speakers themselves, there was nothing I would consider esoteric involved. The listening space wasn't special either (where they will end up will be well treated but where they were auditioned wasn't). A recording that really showed it off, for me, was Pink Floyd's "Money" from the Dark Side of the Moon CD.

[rusty jefferson]

...Like everything else in this hobby, there are many opinions on how to get great imaging. That said, I'm not even sure we are all taking about the same thing when we discuss imaging.

I define imaging as the the speaker's soundstage....

...To me a speaker with outstanding imaging will create a holographic soundstage when playing back recordings that are recorded in a manner where there is the appropriate sonic information. If the recording has been recorded in a manner that preserves spatial details, you may hear sounds apparently coming from deep behind the plane of the speakers as well as infront of them. A vocalist may be so locked into the center there appears to be narrow window from which they are singing, and sounds may appear far to the left or right of the speakers and sometimes sounds or instruments even seem to be behind you. I've heard "audiophiles" refer to this as having speakers that "disappear".

Most speakers will throw some form of image and create a soundstage that is likely not that far off from what we are likely to hear at a typical live musical performance. That said, speakers with outstanding imaging create an immersive soundstage that can be quite compelling. This sort of imaging occasionally occurs in live music, but not typically....

Widget
Thanks for initiating a new thread.

I agree with the above outline of imaging as being the accurate representation of the live recorded umamplified event, from the perspective of the microphones used to record it. That doesn't necessarily mean it's the same experience an audience has, of course. But good imaging is more than the common center image between stereo speakers. As you state, it can be quite compelling. Multi tracked studio recordings don't create this imaging, but may still have an immersive quality. Also, imaging specificity, or the ability to accurately put the various instruments or voices in the proper location in the soundstage is key. Singers in an Opera for example, if singing from the rear of the stage on the right, should be shown there and not heard coming from the right speaker itself.

I'm curious how far from the front wall you've got the 1400 Arrays to help create this image in your new set up. I remember pictures of your previous house where as I recall the Everests and Arrays were positioned quite close to the wall. Few speakers can create a quality image if located near the wall.

[SEAWOLF97]

I find imaging an interesting subject.

When I got my 250Ti's and to a lesser extent the Walsh's , the imaging was
somewhat of a disappointment. I like an immersive , 3D experience. ie:live.

Did some reading on the subject and many sites point to SRS as a solution.

So I bought a Hughes SRS unit and installed. You can widen or narrow the sound field,
move the center closer or further away, even move sounds behind you ...
ie: tune the image to your desires.

The technology (as I understand it) was designed for military flight simulators.

Now before you respond "I don't want no fuggin addons in MY system", understand
that SRS (now morphed into DTS) has been installed in most TV sets produced since 2009
and seems to everywhere.

https://dts.com/history

I can, of course, turn it off .. but that renders things "lifeless" and most people that I've seen
do not like it that way. :o:

[Ian Mackenzie]

Absolute symmetry of the location of the L & R loudspeakers is important for imaging. This includes toe in, front and side wall distance. Balance of the individual drivers levels and source of L & R levels is also important.

A little known fact is that the L & R level of a vinyl cartridge can vary +- 1.5 dB. Careful adjustment of a tone arm and test equipment can minimise this.

Tracking of the volume control L & R can also impact significantly on the imaging.

[Mr. Widget]

Without a doubt, the M2s had the best imaging I've ever heard from any pair of speakers, anywhere at any time.I have heard that from others as well. I'm not sure why my take away was different. To me the best feature of the speakers was the bottom end. Between the design of the driver and the electronic tuning I found the bass to be quite compelling.


Furthermore, you don't have to sit equidistant with them. There is a lot of latitude with where you are sitting/standing.I did notice this aspect to the M2s. I thought they imaged quite well through a fairly wide space. That said, the speakers were set up in an equidistant triangle and they worked well over a wider range than many speakers. The best speakers that I have heard from the perspective of wide sweet spot have been some crazy expensive 7' tall line source speakers.



I agree with the above outline of imaging as being the accurate representation of the live recorded umamplified event, from the perspective of the microphones used to record it. That doesn't necessarily mean it's the same experience an audience has, of course. But good imaging is more than the common center image between stereo speakers. As you state, it can be quite compelling. Multi tracked studio recordings don't create this imaging, but may still have an immersive quality. Also, imaging specificity, or the ability to accurately put the various instruments or voices in the proper location in the soundstage is key. Singers in an Opera for example, if singing from the rear of the stage on the right, should be shown there and not heard coming from the right speaker itself.Yep, I have heard a few examples of stereo magic that was pure fiction – created in a studio, but typically the best examples of great imaging are well captured live events.




I'm curious how far from the front wall you've got the 1400 Arrays to help create this image in your new set up. I remember pictures of your previous house where as I recall the Everests and Arrays were positioned quite close to the wall. Few speakers can create a quality image if located near the wall.They are currently about 3' from the front of the speakers to the wall behind them and perhaps ten feet from each speaker to the side walls. Also, the listening position is about 6' from the wall behind me with a vaulted ceiling so all reflections are significantly delayed from the first arrival.



Absolute symmetry of the location of the L & R loudspeakers is important for imaging. This includes toe in, front and side wall distance. Balance of the individual drivers levels and source of L & R levels is also important.Yep, and as a continuation of my above description, my new listing room and the layout is quite symmetrical and filled with items that are elements of decor but function as diffusers.



A little known fact is that the L & R level of a vinyl cartridge can vary +- 1.5 dB. Careful adjustment of a tone arm and test equipment can minimise this.Good point and one reason that back in the day getting a solid central image was so elusive.


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[Ducatista47]

In my listening history, one pair of small single driver speakers imaged so well they blew away all that came before. They are Omega TS2Rs, a model with 6.5 inch Fostex drivers that came out around 2002. At 94dB/watt/meter efficiency they are not difficult to drive. I first heard them powered by a small tube amp and later by a First Watt F2J. (The imaging was similar but the bass response was extended much lower with the latter, being a transconductance design. Everyone who has heard the TS2R/F2J combination asked about what subwoofer was being used. None was, of course.)

Sorry to digress, but I needed to establish that when properly driven this small speaker has none of the weaknesses normally associated with single driver speakers. The imaging is far beyond anything else I have experienced, excepting my own Hammer Dynamics Super 12s, which are in the same class but cannot replicate the ultra pinpoint nature of the Omega's imaging. Close though. Both share the ability to make one swear there are instruments four feet outboard of either speaker; soundstage is excellent. I have since gone to a bunch of big audio shows and have yet to hear anything remotely close to those little Omegas in imaging and rarely in the soundstage department. (This year in Chicago I did experience a million dollar class system that soundstaged brilliantly in a huge room, but that is what it took.)

For the well-heeled I can recommend an equally rewarding but different experience, the MBL Radialstrahler 101 E MK II speakers set up in a good room. Their omnidirectional presentation is perfectly executed and the sound field is so thrillingly immersive you forget all about the usual imaging impressions and considerations. I think they are about forty grand US a pair. The Europeans who report to my friend Dave (the TS2R owner btw) say the big shows over there have never had the MBLs set up well and it makes a huge difference, negatively. I have found through repeated listenings that the larger MBL system at $277K a pair has no advantage in a room of typical living room dimensions. In fact, I liked the smaller system better. Unlike the single drivers, where the sweet spot is rewarded, the MBLs don't care where you sit, or even if you sit. The experience is not like listening to a pair of speakers; it is a you-are-there feeling.

A boring TS2R audiophile review but it has pictures of the mighty mites. What might look like a tweeter is a port.

https://www.tnt-audio.com/casse/omegats2r_e.html

[SEAWOLF97]

A big contributor to the imaging of a system is the beamyness
of the HF drivers. My 250Ti's do not seem to have much width
of coverage despite the SRS.

IE: The "sweet spot" is not terribly wide. :( easy to loose.

There are 3 systems in my living room. The 250's , Walsh's and
ESS AMT bookshelves. I overwhelmingly spend more time with
the smaller boxes. The image is wide and precise.

The Heil driver covers the mids & highs (they are a 2 way system with
a 10 in. LF and 10 in. passive radiator). Just a sweet pair of speakers.

I judge a speaker by how long it stays in the house. Have had many fine
ones rotate through, but didn't turn out to be keepers.

Although the big 4 ways are a good example of complex engineering, I
usually seem to gravitate to 2 way speakers.

I did have a KEF Q series pair that were fantastic imagers (tho lacking much bass),
but not the total package that I was looking for ... :o:

[rusty jefferson]

.....They are currently about 3' from the front of the speakers to the wall behind them and perhaps ten feet from each speaker to the side walls. Also, the listening position is about 6' from the wall behind me with a vaulted ceiling so all reflections are significantly delayed from the first arrival....
Widget
I like that you can have them so far from the side walls, but I'm surprised that only 3 feet from the front wall you're experiencing such good depth, and in particular good depth behind the speakers themselves. That's unusual in general, and especially with horns.


In my listening history, one pair of small single driver speakers imaged so well they blew away all that came before. They are Omega TS2Rs, a model with 6.5 inch Fostex drivers that came out around 2002....

...The imaging is far beyond anything else I have experienced, excepting my own Hammer Dynamics Super 12s, which are in the same class but cannot replicate the ultra pinpoint nature of the Omega's imaging. Close though. Both share the ability to make one swear there are instruments four feet outboard of either speaker; soundstage is excellent...
Yes, as mentioned in the other thread, the idea of a small point source. Mounted in a non-resonant sphere, it would be even more spectacular. Excellent dispersion through the critical mid frequencies. That ability to locate instruments/voices many feet wider than and many feet behind the speakers is just amazing.


A big contributor to the imaging of a system is the beamyness
of the HF drivers. My 250Ti's do not seem to have much width
of coverage despite the SRS.

IE: The "sweet spot" is not terribly wide. :( easy to loose.

And this is where we picked up with the L-112 crossover thread. The 250s have about the same 5k crossover point at the mid/tweeter as the L-112. Perhaps the mid is beaming? Troels Gravesen tried initially to lower the crossover point to 3k but was unsuccessful. He didn't say why. The narrower and radiused baffle of the 250 should help reduce diffraction compared to the L-112.



...There are 3 systems in my living room. The 250's , Walsh's and
ESS AMT bookshelves. I overwhelmingly spend more time with
the smaller boxes. The image is wide and precise.

The Heil driver covers the mids & highs (they are a 2 way system with
a 10 in. LF and 10 in. passive radiator). Just a sweet pair of speakers....

That Heil tweeter is doing all the work above 1k and probably has excellent dispersion of both drivers at crossover. That's another very interesting philosophy. In the 250, the mid woofer/mid crossover is 1.4k.

[Ian Mackenzie]

A big contributor to the imaging of a system is the beamyness
of the HF drivers. My 250Ti's do not seem to have much width
of coverage despite the SRS.

IE: The "sweet spot" is not terribly wide. :( easy to loose.

There are 3 systems in my living room. The 250's , Walsh's and
ESS AMT bookshelves. I overwhelmingly spend more time with
the smaller boxes. The image is wide and precise.

The Heil driver covers the mids & highs (they are a 2 way system with
a 10 in. LF and 10 in. passive radiator). Just a sweet pair of speakers.

I judge a speaker by how long it stays in the house. Have had many fine
ones rotate through, but didn't turn out to be keepers.

Although the big 4 ways are a good example of complex engineering, I
usually seem to gravitate to 2 way speakers.

I did have a KEF Q series pair that were fantastic imagers (tho lacking much bass),
but not the total package that I was looking for ... :o:

It must be fun having 3 systems in one room.

But l wonder if you are actually happy with any of them unless you like hoarding vintage loudspeakers?

Can you advise if you change out each system for exact same location?

[Mr. Widget]

I like that you can have them so far from the side walls, but I'm surprised that only 3 feet from the front wall you're experiencing such good depth, and in particular good depth behind the speakers themselves. That's unusual in general, and especially with horns.I would assume it is due to these particular speakers having really well controlled directivity, but that is just a guess.


Yes, as mentioned in the other thread, the idea of a small point source. Mounted in a non-resonant sphere, it would be even more spectacular. Excellent dispersion through the critical mid frequencies. That ability to locate instruments/voices many feet wider than and many feet behind the speakers is just amazing.It has been my experience that as a group, mini monitors or other small point source speakers like the T2SRs that Clark mentioned are typically the best at "imaging"... though numerous other designs can also be surprisingly good. Large 4-ways are typically not the best performers of this type of spooky imaging.


Widget

[SEAWOLF97]

It must be fun having 3 systems in one room.

we rarely use that living room. no TV , just a place to sit and talk or listen to tunes while minding the wood stove.



But l wonder if you are actually happy with any of them ...?

I love the ESS's, F2's and 120Ti's. When people SEE the 250's they are very impressed, while the Walsh's are invisible, people walk right past them. But that all changes when I put signal to them.
The old family room (now bedroom/man cave/home theater/office) has the a/d/s towers and a/d/s surrounds,def tech powered center/sub,velodyne sub, 2 bic subs, the computer has 120Ti's and a pair Sonances
My work area has Pinnacles and L19's needing refoaming
Other bedroom has AR towers, M&K sub, some B&O's and ....
Storage has ..............more ESS's , 18Ti's and ..............:dont-know:
Oh yeah, there's an M&K sub in the front room.

Don't even ask about headphones :o:



Can you advise if you change out each system for exact same location?

The LR system started with L100's, then L26's and L36's, then 4410's,4412's, AR3's,L88's, L65's, smaller Walsh's, Ohm F's and then F2's .... the F's were in the spot where the 250's now are and were connected to the same gear. I've sold or given away so many speakers that I can't even remember them all. :crying:

The bedroom system had L7's and they were great for cinema (also had powered AR towers there),
but the JBL's wern't right in that area, the AR's were great for movies .. but not for music. The big
a/d/s towers were best compromise for that application,amp/electronics


unless you like hoarding vintage loudspeakers?

I sold off/gave away 54 pairs in one frenzy about 2-3 years ago ..they mostly went to Asia.

[Ducatista47]

It has been my experience that as a group, mini monitors or other small point source speakers like the T2SRs that Clark mentioned are typically the best at "imaging"... though numerous other designs can also be surprisingly good. Large 4-ways are typically not the best performers of this type of spooky imaging.


Widget
My low tech guess about why my 4345s suck pond water at imaging is that their baffles are too damn big to pull it off. ...but from what you say about the M2s, perhaps not. I have noticed that when sitting on the floor in front of them, the stereo image kicks in incredibly close to the baffles. Not much over a foot.

[Mr. Widget]

My low tech guess about why my 4345s suck pond water at imaging is that their baffles are too damn big to pull it off. ...but from what you say about the M2s, perhaps not. I have noticed that when sitting on the floor in front of them, the stereo image kicks in incredibly close to the baffles. Not much over a foot.I think there are many reasons why the 4345s are not imaging champs. Interestingly years ago when Bo and I swapped out his 2421Bs for a pair of TAD TD-2002s the image in his pair of 4345s improved a bit... no idea why it would.

The big baffle certainly can't help, but then the Everest IIs with an even wider baffle image surprisingly well. Certainly not like the M2s or 1400 Arrays or a really great point source, but considering they take over the room visually, they almost "disappear".


Widget

[rusty jefferson]

Large baffles and cabinet diffraction are definitely image killers. I think there has to be something special about those horns on the Array not being in a cabinet. Have we ever seen polar plots for those? Is the crossover point low enough between the woofer and midrange horn to prevent the woofer beaming?

When I stood 6 ft behind my large format monitors all you heard was bass making it's way to the rear side. Good coherent center image at the listening position, but no soundstage image. The speakers I'm experimenting with now which are a low diffraction design sound almost the same 6 feet behind them as they do standing 6 feet in front, similar to a planer/electrostat. They have a good soundstage image like we've been talking about. All the music is positioned behind the speakers on live recordings, and you don't hear the speakers (transparent).

[rusty jefferson]

There's a tool on one of the Stereophile test cds (number 3 track 10) that I've been using a lot lately both on my system and others. This used to be a left to right pan across my living room, but now I understand what they are demonstrating. JA is so far behind the speakers and to the sides it's remarkable (with variations based on microphone). Here's a description of what you should be hearing as it plays.
https://www.stereophile.com/content/istereophilei-test-cd-3-tutorial-tracks-microphone-techniques

[Ian Mackenzie]

One of the problems with imaging in the 4345 is setting up the Lpads.

I have had very good feedback on the imaging after precision calibration of all the drivers levels and matching L & R drivers. This requires-+.2 dB matching.

Once that is done correctly they disappear with well recorded classical Music.

I find they need to be 2.5-3 metres apart. They then open up a deep and expansive sound stage. This means a large room.

In most cases the enclosure needs to be raised up 6 inches to obtain the correct tonal structure and image correctly

[SEAWOLF97]

They have a good soundstage image like we've been talking about. All the music is positioned behind the speakers on live recordings, and you don't hear the speakers (transparent).

Last time I'll mention the Walsh's (at least in this thread ;) )

Had a guest who wanted to hear the 250Tis. They are on one side of the room (flanking the woodstove) and the W's are on the opposite side of the room with the electronics.

Powered up the system (it controls both sets of speakers - BGW preamp has 2 outputs, they go to separate BGW amps, one amp to each speaker pair) , anyway the last config was the W's playing and JBL's were off.

Listener had his back to the W's and was facing the 250's. He remarked that the 250's sounded great.I gave a funny look and he asked "what ??", I said "put your ear up to them" ... after doing so, his reply was "Hell, they aren't even playing, where is the music coming from ????"

[Ducatista47]

I find they need to be 2.5-3 metres apart. They then open up a deep and expansive sound stage. This means a large room.

In most cases the enclosure needs to be raised up 6 inches to obtain the correct tonal structure and image correctly
I have never lost sight of the fact that 4345s were designed to be soffit mounted. This was common for mains in those days, I have been told. Westlake had the same recommendations. I know Subwoof has the carpentry skills to do so, certainly a rare skill set, but I am unaware of any home installations that are soffit mounted. At over four hundred pounds for a Westlake and 230 for a 4345, I can see why. But I wonder how it would compare to a six-inch lift. I trust JBL engineers and I assume their speaker sounded significantly better in some important respect up there. Maybe it was soundfield related.

[rusty jefferson]

I have never lost sight of the fact that 4345s were designed to be soffit mounted....

....I trust JBL engineers and I assume their speaker sounded significantly better in some important respect up there. Maybe it was soundfield related.
I imagine that soffit mounted speakers had smoother response because of reduced diffraction. There is no soundstage behind soffit mounted speakers though, and it isn't important to a studio engineer. Head in the vise imaging was okay with them. The concern was probably for flat response, and low distortion at high volume.

[Mr. Widget]

I find they need to be 2.5-3 metres apart. They then open up a deep and expansive sound stage. This means a large room.In my experience this spacing works best with most speakers. Most of my systems ended up in this range even if the room is huge and the listener can be back further and there is ample room to push the speakers wider apart. I have found I prefer 9-10' between the speakers and that same distance to the listener.

I'm not sure if this is a personal preference or a more universal thing.


Widget

[Ian Mackenzie]

Hi Clark,

Nice of you to chime in.

I don’t think sofit helps imaging as much as low frequency smoothness and midrange clarity.

The problem is if listening height is above the bottom of the lens they don’t image as well or sound tonally balanced.

Hi Widget,

I agree but then the 4345 l have tried a 2 metre triangle and it did not work. They would not image and sounded closed in and bright so matter what l did.

My smaller (JBL) room is 4.7 x 4.2 metres and l have them on the long wall evenly spaced with velvet drapes on the side and rear double glazed windows. The room is well furnished with book cases and sofas. The listening distance is about 3 metres. A don’t find a shorter distance nearly as effective.

I think it’s because the baffles act as large reflectors as opposed to diffusers like typical narrow baffle towers.

All things being proportional a bigger loudspeaker works better in a bigger space.
I have seen many set ups where they are squeezed into a narrow room and this is a compromise.

I think the room is important with larger loudspeakers.

I intend to try the 4345’s in my larger 5 x 9.5 metre room with 3.5 metre ceiling. This room has large 2.6 metre high glass sliding doors on each side that can be opened to form a large listening space.

I am probably biased but the latest Pass electronics with a hint of negative phase in the second harmonic with the SE bias provide glorious depth at normal listening levels. It’s doesn’t get any better.

[rusty jefferson]

.....That said, I'm not even sure we are all taking about the same thing when we discuss imaging....
Widget
I am realizing now how right this statement is. :)

[Ducatista47]

Thanks to all involved for setting me straight about soffit mounting. There is a reason I normally only post about music here! Hopefully, I haven't steered anyone wrong about that too. And no, I didn't expect anyone in particular to enjoy Cowboy Junkies' steady diet of sad, sad songs. I will stick by Michael Timmins being the best lyricist of the last thirty plus years that I am aware of.

[speakerdave]

Based on my experience with a) 4345's; b) numerous 2- and 3-way direct driver speakers in indifferent boxes; c) two-ways with a fifteen or fourteen crossed in the hundreds to a "windswept" horn on top of the woofer cabinet; d) small full ranges; e) Altec 604's; f) Tannoy/Manley time aligned ML10's vs the same 2558 D.C. driver in the stock, non-time aligned SGM 10B, I would say good imaging depends on the speakers tracking frequency response and also tracking coherent phase response, absence of diffracting edges and good placement with reflection management. There are multiple ways to get there.

[1audiohack]

Hi Clark and All;

For the record, I love Cowboy Junkies.

Does the magic effect work outdoors in a non reflective space? It sounds as if what wraps around the speaker and is reflected from behind is an important part of the equation?

I should take my best point sources outside and compare their performance in open space.

Barry.

[rusty jefferson]

..... And no, I didn't expect anyone in particular to enjoy Cowboy Junkies' steady diet of sad, sad songs. I will stick by Michael Timmins being the best lyricist of the last thirty plus years that I am aware of.
:)Clark, Come on, that's gotta be Tom Waits!

[rusty jefferson]

....Does the magic effect work outdoors in a non reflective space? It sounds as if what wraps around the speaker and is reflected from behind is an important part of the equation?

I should take my best point sources outside and compare their performance in open space.

Barry.
Barry, excellent question. It does not. The best imaging I've heard were in highly diffracted (not difused) rooms. Reflections are critical but properly scattered/delayed.

If your point source is capable, you may hear more than just bass standing behind them, but you won't get the sense of the performance space.

[Ducatista47]

:)Clark, Come on, that's gotta be Tom Waits!
Well, Tom is a lot more upbeat and pretty funny too. I remember him saying on a talk show he had been staying in an exclusive hotel chain. "It's called 'Rooms'". In fact, his romantic notions about being poor in style were no put on. Ricky Lee Jones, his ex-wife, complained that despite her good record sales "He wanted us to live like poor Mexicans". I guess you could say there is only one Tom Waits.


Barry, excellent question. It does not. The best imaging I've heard were in highly diffracted (not difused) rooms. Reflections are critical but properly scattered/delayed.

If your point source is capable, you may hear more than just bass standing behind them, but you won't get the sense of the performance space.
This may be germane to this thread's topic: Why do some speakers sound better when you take them outdoors? I don't recall ever encountering this experiment when the indoor location was well treated for acoustics.

[Ian Mackenzie]

What l find odd is that you can take a hi fi loudspeaker that was engineered from the ground up to image well with all the points noted above and for what ever reasons it does not image with the same realism as a loudspeaker with design focus in other areas.

What l am referring to is a point source for example is not in itself the final arbiter as far as actual listening is concerned.

The way individual musical instruments appear in space in terms of their individual scale, tonal density and the ambiance around them while other instruments are clearly defined elsewhere is important. Of course like so many aspects of sound reproduction what you don’t hear (or are aware of) you don’t know and don’t miss.

I have heard a number of point source loudspeaker such as Tannoys, Altec 604’s, PHL coaxials, Fostex full range and multiway D’Appolito systems.

The problem is the limitation of engineering such designs

Not everyone listens for the same qualities either.

I also firmly believe we do a lot of listening with our eyes.
Perhaps a bit off topic but here is the thing. Yesterday l was in a train coming back from Chateau Versailles just outside Paris and l was half asleep (which my wife says is not unusual). Well all of a sudden a busker started playing and singing a tune across the isle. With my eyes closed l could obviously hear the busker and where sound was coming from. But with my eyes open it was more defined and more real as in there is an added sense of specifically where the guitar and voice were coming from.

You might say l am stating the obvious but Floyd (?) in one of Harman’s presentations discusses this phenomenon.
We apparently do a lot of listening with our eyes. This is why visual room symmetry and the appearance of loudspeaker baffles becomes relevant to how you process audible and visual sensory experiences.

This leads me to think that some recordings are possibly more nuanced as far as imaging goes by the producer than perhaps in reality so the listening is an engaging and satisfying experience.

[marco_gea]

On a recent thread: http://www.audioheritage.org/vbulletin/showthread.php?41068-Anyone-tried-the-Troels-Gravesen-L112-upgraded-crossovers one of several divergent topics from the original topic dove into the discussion of imaging.

Like everything else in this hobby, there are many opinions on how to get great imaging. That said, I'm not even sure we are all taking about the same thing when we discuss imaging.

Based on some of the responses in this very thread, I doubt we all are (talking about the same thing)...



I define imaging as the the speaker's soundstage. In my opinion for there to be imaging you typically do need to have a setup where you can sit at an equidistant vertex of a triangle. I realize for many this is simply not possible. While it is still possible to have a very satisfying musical experience I don't think outstanding imaging will be possible.

100% agreed (bold emphasis mine).

I would add that a true test for the ability to reproduce such an illusion of "soundstage" must start with a recording where natural, low-level acoustical cues of the original recording space are present in the first place. Multi-mike, multi-tracked, artificially pan-potted recordings - such as e.g., The Dark Side of The Moon mentioned in another post in this thread - can certainly sound immersive and impressive in their own right, but they aren't the right tool to ascertain a system's ability to truly "image", in my opinion.

Marco

[marco_gea]

Absolute symmetry of the location of the L & R loudspeakers is important for imaging.
Yes, this is always true.


This includes toe in, front and side wall distance.
The importance of equal side wall distance depends on the horizontal directivity of the speakers, especially in the mid range. The higher the directivity, the less sensitive the speakers' imaging potential is on the proximity of the side walls.


Balance of the individual drivers levels and source of L & R levels is also important.

A little known fact is that the L & R level of a vinyl cartridge can vary +- 1.5 dB. Careful adjustment of a tone arm and test equipment can minimise this.

Tracking of the volume control L & R can also impact significantly on the imaging.
Yep!

[marco_gea]

In my listening history, one pair of small single driver speakers imaged so well they blew away all that came before. They are Omega TS2Rs, a model with 6.5 inch Fostex drivers that came out around 2002. At 94dB/watt/meter efficiency they are not difficult to drive. I first heard them powered by a small tube amp and later by a First Watt F2J. (The imaging was similar but the bass response was extended much lower with the latter, being a transconductance design. Everyone who has heard the TS2R/F2J combination asked about what subwoofer was being used. None was, of course.)

...

For the well-heeled I can recommend an equally rewarding but different experience, the MBL Radialstrahler 101 E MK II speakers set up in a good room. Their omnidirectional presentation is perfectly executed and the sound field is so thrillingly immersive you forget all about the usual imaging impressions and considerations. ...


I agree on the single driver experience. Good imaging can be one of the strong points of well-implemented so-called "full range" drivers, especially those without "whizzer" cones, which create all sorts of phase issues of their own.

I strongly disagree about the MBL's, though. I have heard them many times, and they invariably superimpose the same overly spacious and "reverberant" (for lack of a better way to descibe it) rendition on pretty much any music that is fed to them. To me, that is not good imaging, but fake imaging. From a technical standpoint, I think it results from excessive early reflections from the listening room's walls swamping the low-level spatial cues that are present in the recording.

[marco_gea]

My low tech guess about why my 4345s suck pond water at imaging is that their baffles are too damn big to pull it off. ...but from what you say about the M2s, perhaps not. I have noticed that when sitting on the floor in front of them, the stereo image kicks in incredibly close to the baffles. Not much over a foot.

It has much more to do with their relatively crude crossover, which does not pay much if any attention to inter-driver phase tracking.
The width of the baffle per se is only of secondary relevance, especially with high-directivity mid-hi frequency drivers such as those.

[marco_gea]

There is no soundstage behind soffit mounted speakers though.

With all due respect, I think this is an unsubstantiated blanket statement.

What soffit mounting precludes is additional artificial "spaciousness" created by in-room reflections from the front wall. But this has little to do with properly reproducing the soundstage cues that are present in the recording (if they are there to begin with, of course!)

[marco_gea]

In my experience this spacing works best with most speakers. Most of my systems ended up in this range even if the room is huge and the listener can be back further and there is ample room to push the speakers wider apart. I have found I prefer 9-10' between the speakers and that same distance to the listener.

I'm not sure if this is a personal preference or a more universal thing.


Widget

FWIW, I found the same. Sitting at the apex of an approximately 3-metre side equilateral triangle is the "sweet spot" in speaker-listener positioning.

[marco_gea]

Based on my experience with a) 4345's; b) numerous 2- and 3-way direct driver speakers in indifferent boxes; c) two-ways with a fifteen or fourteen crossed in the hundreds to a "windswept" horn on top of the woofer cabinet; d) small full ranges; e) Altec 604's; f) Tannoy/Manley time aligned ML10's vs the same 2558 D.C. driver in the stock, non-time aligned SGM 10B, I would say good imaging depends on the speakers tracking frequency response and also tracking coherent phase response, absence of diffracting edges and good placement with reflection management. There are multiple ways to get there.

Yes!

[rusty jefferson]

With all due respect, I think this is an unsubstantiated blanket statement.

What soffit mounting precludes is additional artificial "spaciousness" created by in-room reflections from the front wall. But this has little to do with properly reproducing the soundstage cues that are present in the recording (if they are there to begin with, of course!)
I feel the point is, the "spaciousness" and localization of performers is not artificial. It's time delay of the instruments or voices to the microphone(s) and reflections in the theater environment also picked up by the microphones. Played back on soffit mounted speakers, there will be no reproduction of the "actual" instruments/voices in space in the proper location, behind the loudspeakers, as the performers were behind the microphones.

Please see post #16 about the Stereophile Mapping the Soundstage track. Playing that track back on soffit mounted monitors will simply be a left to right pan on plane with the loudspeakers.

[Robh3606]

Multi-mike, multi-tracked, artificially pan-potted recordings - such as e.g., The Dark Side of The Moon mentioned in another post in this thread - can certainly sound immersive and impressive in their own right, but they aren't the right tool to ascertain a system's ability to truly "image", in my opinion.

Hello Macro_gea

Maybe not but they can make excellent set-up tools from system to system and typically if you can get the best out of them a more natural imaged piece is quite easy to hear. I use a couple of specific recordings that I know well to set-up my speakers in my systems. I also find that with that type of recording the imaging changes from song to song from the differences in mix down from song to song. I agree about speakers that superimpose there characteristics by design over recordings. In my mind they should all be different especially in multitrack recordings and it should be easy to hear the differences from song to song even on the same CD/Album.

Rob:)

[1audiohack]

I feel the point is, the "spaciousness" and localization of performers is not artificial. It's time delay of the instruments or voices to the microphone(s) and reflections in the theater environment also picked up by the microphones. Played back on soffit mounted speakers, there will be no reproduction of the "actual" instruments/voices in space in the proper location, behind the loudspeakers, as the performers were behind the microphones...

I don’t mean to be contrary but if the cues are in the recording, anything that wraps around the speakers and comes back to the listener must be considered an alteration and an addition to the recorded original.

It seems to me that if a speaker pair can create an image or perceived placements of sounds wider than themselves and deeper than themselves that information should be in the time and space cues of the material and as long as the acoustic space is inert like outdoors or soffit mounted in an infinite baffle, or in a symetrical room properly treated, the effect should be detectable.

If you hold that the sound must interact with the space, then it’s the space.

I understand how an asymmetrical space will damage the effect.

If this is not so, please tell me how and why?

Again, I am not attempting to be contrary but to understand.

Thank you all.
Barry.

[1audiohack]

I did not mean to kill the conversation!

Should I delete my questions and observations and just spectate?

Barry.

[rusty jefferson]

Hey Barry,

I was thinking how I could explain the physics to your questions/points, but honestly, I'm not smart enough. :) So here's a link to a page at the Linkwitz website that may help explain it properly. http://www.linkwitzlab.com/The_Magic/The_Magic.htm (http://www.linkwitzlab.com/The_Magic/The_Magic.htm) I'm not promoting Linkwitz products, but thought him to be a reliable source.

The room is a very important factor for imaging. Properly time delayed reflections are critical as are many of the things previously discussed, great off axis response (including dipole), low diffraction cabinets (or no cabinet), wide dispersion as from the small point source, etc. To hear the instrument 4-5 ft. beyond the width of the speakers as Clark mentioned, or JA banging the cowbell on the left/right side of the stage on the test track showing as being behind the loudspeakers, you need delayed reflections. It won't happen in an anechoic chamber or with soffit mounted monitors (especially in an acoustically dead studio setting). The sound will be "stuck on the speakers" if you will. They will not disappear.


Here's a paragraph from the link above, and this quote from another section. I like how he refers to imaging as the magic, as you did in an earlier post.
"The magic is difficult to describe in pictures or words but is recognized within 30 seconds when heard. It usually elicits a big smile or even laughter from the listener. Naive listeners, audiophiles and professionals alike recognize the naturalness of presentation. On many recordings it is 3D in front of the listener and resembles a concert experience..."
3.2.1 Loudspeaker & Setup Requirements
For the magic to occur there are five requirements, which I have found to be essential:


The off-axis frequency response of the loudspeaker in the horizontal plane must mimic the on-axis response. The vertical polar response is not as critical but the formation of lobes should be avoided, i.e. the loudspeaker should be acoustically small. Such a loudspeaker has a neutral signature and its reflections and the reverberated sound field will have the spectral signature of the listening room. The polar pattern could be omni-directional, cardioid or dipolar with frequency independent power response. The omni pattern would produce the strongest interaction with the room and be the least desirable of the three.
The loudspeakers must be free of resonant radiation such as coming from vents or panels. Non-linear distortion must be low enough not to identify the speaker location during loud music passages. This demands adequate volume displacement capability of woofers and tweeters.
The loudspeakers must be set up at least 1 m distance from left and right side walls and 1 m from the wall behind them. The resulting time delay of about 6 ms is necessary for the ear-brain perceptual apparatus to separate direct from reflected sound streams. With neutral excitation of the room response, the listener can then withdraw attention from the room and process primarily the direct sound streams from the loudspeakers. This is similar to not hearing the ticking clock or to the cocktail party effect where attention and hearing is drawn to information streams of interest. Everything else is moved beyond the acoustic horizon as in survival mode.
The wall behind the loudspeakers is preferably diffusive and the wall behind the listener absorptive. The sound waves from the loudspeaker should be allowed to travel freely past the listener and not be reflected from a wall behind.
The listening room should have a reverberation time around 450 ms, i.e. be neither acoustically dead nor overly live but comfortable for conversation and entertainment. If anything it should err in the direction of liveliness.

[marco_gea]

To hear the instrument 4-5 ft. beyond the width of the speakers as Clark mentioned, or JA banging the cowbell on the left/right side of the stage on the test track showing as being behind the loudspeakers, you need delayed reflections. It won't happen in an anechoic chamber or with soffit mounted monitors (especially in an acoustically dead studio setting). The sound will be "stuck on the speakers" if you will. They will not disappear.


Sorry, I don't have time for a complete response to your long post. But I can assure you that this particular assertion is demonstrably wrong.

For instance, the first track on Roger Waters' "Amused to Death" has a barking dog that's supposed to sound as coming from far away, and way outside of the triangle defined by the physical position of the speakers (I forget now whether further to the right w.r.t the right speaker, or to the left w.r.t the left one).

I have listened to that track on a large number of systems, including soffit mounted ones, as well as on my own, where the speakers are floor-standing but positioned right up against the front wall. And I can assure you that - with all speakers having properly designed crossovers - the dog always sounds exactly where it is supposed to sound, i.e. behind and outside of the triangle defined by the physical position of the speakers.

Marco

[Ian Mackenzie]

Hi Rusty and Marco,

This is a good discussion and l found a few useful links on imaging techniques as applicable to recordings and loudspeakers below.

In the last link reference is made to creation of stereo imaging in the “mix”.

I have no doubt that plugins used to enhance or create interesting stereo reproduction would be frowned upon by engineers devoted to traditional mike techniques of classical recordings. To that end l crave for well recorded classical music in the analogue domain.

I also post a quote regards my comments about the use of imaging in stereophonic recordings to creat interest.


Paul Wilson

https://audiophilereview.com/audiophile-news/is-stereo-imaging-overrated.html

“Imaging makes recorded music sound decidedly more interesting. It calls the listener to become more involved with the music. It makes the listener almost think he or she is at a live concert. Spatial cues in terms of musical depth and width provide an added dimension of realism to recorded music.

Imaging has the ability to make music more interesting. Hearing a musical presentation made in a realistic fashion may transport the listener to a time remembered - maybe a favorite concert, or some memorable past event.”

https://en.m.wikipedia.org/wiki/Stereo_imaging

Quote

“The quality of the imaging arriving at the listener's ear depends on numerous factors, of which the most important is the original "miking", that is, the choice and arrangement of the recording microphones (where "choice" refers here not to the brands chosen, but to the size and shape of the microphone diaphragms, and "arrangement" refers to microphone placement and orientation relative to other microphones). This is partly because miking simply affects imaging more than any other factor, and because, if the miking spoils the imaging, nothing later in the chain can recover it.

If miking is done well, then quality of imaging can be used to evaluate components in the record/playback chain (remembering that once the imaging is destroyed, it cannot be recovered).“

https://www.waves.com/tips-for-wider-stereo-mix

I hope everyone finds this productive to the discussion.

Ian

[Ian Mackenzie]

This link provides basic information about the impact of acoustics on stereo image

https://www.google.com/amp/s/www.crutchfield.com/ISEO-rgbtcspd/amp/learn/learningcenter/home/speakers_roomacoustics.html

https://www.gikacoustics.com/audiophile-2-channel-listening-room-acoustics/

[rusty jefferson]

Marco, I would suggest that dog bark was placed in the recording using phase tricks. This can be heard on many studio recordings where guitars and such are diffusely heard outside the speakers. We've been talking about live unamplified performances recorded in an acoustic space, and trying to recreate that space at home.

Ian, thanks for the links. It is a good discussion.

[Ian Mackenzie]

There is a doco on that album

It was all experimental with a lot of improvisation

[rusty jefferson]

Bless the Google, I know what a doco is now. :)

[marco_gea]

Paul Wilson

https://audiophilereview.com/audiophile-news/is-stereo-imaging-overrated.html



Interesting discussion in the comments section of that page.

Mr. Ethan Winer said:
"Imaging has nothing to do with distance to the front wall unless you have dipole type speakers like Magnepans etc. Imaging is about mid and high frequencies, and normal "box" and tower type speakers send those frequencies forward, away from the front wall. The side wall distance could affect imaging, but only if the absorption isn't effective enough. I've seen people use diffusion at side-wall reflection points, and that too would affect imaging versus distance. Though IMO a normal width room should not have diffusion there because it's not as effective as absorption."

Based on my own experience, I would tend to agree - especially if the speakers have directional mid-highs (as is the case when using waveguides/horns).

Marco.

[marco_gea]

Marco, I would suggest that dog bark was placed in the recording using phase tricks. This can be heard on many studio recordings where guitars and such are diffusely heard outside the speakers. We've been talking about live unamplified performances recorded in an acoustic space, and trying to recreate that space at home.


True. Fair enough.

But I could also quote other recordings that lead me to draw the same conclusions.

For instance, I have a recording of the first movement of Saint-Saens' Symphony n.3 in C minor (the one for orchestra and organ) which - when played back on my system (which, again, is not strictly soffit mounted, but in which the speakers are right up against the front wall) gives an uncanny impression of depth, with the front wall virtually disappearing and the listening room appearing much deeper and wider than it really is.

Unfortunately, I obtained this rather spectacular recording as part of a CD-R mix used by an audio manufacturer as their "demo CD", and I haven't been able to find out the label under which it was originally released :-(
But I am quite sure that it is most definitely not a processed recording where the recording or mixing engineer used "phase tricks" like the ones used on the Roger Waters album.

Fundamentally, I think the issue at play is that there are two factors that contribute to the impression of depth and width: (1) the recording venue reflections and low-level reverberation captured in the recording itself, and (2) the listening room reflections.

Some people (including myself) prefer a listening experience where - at the listening position - the direct sound from the loudspeakers is louder than that from the reflected sound from the listening room. In other words, we like to listen at D < Dc (where Dc = "critical distance"). This is only feasible if using fairly directional speakers (e.g., DI > 8 - 10 in the mid-high frequencies) in rooms that are not too "lively". In these conditions, the depth cues in the recording (1) dominate over the listening room reflections (2).

Other people enjoy the additional (but I would also argue, "fake" - in the sense that it is extraneous to the original recording venue acoustics) "ambience" given by raising the level of the room reflections (2). This is accomplished by using low-DI speakers in lively rooms and listening in the far field (D > Dc). An extreme example of this type of listening experience is given by the use of MBL omnis in large, sparsely furnished and marble-floor rooms.

In the end, there is no "right" or "wrong" way to enjoy music. To each their own.

[speakerdave]

If phase tricks can make a dog sound like it's barking from far away, then they must be replicating the phase events that occur naturally when a dog barks from far away and their use would not moot the subjective effect of a dog barking from far away when discerned with soffit mounted speakers and would not disprove anybody's notion that soffit mounted speakers can present stage depth.

I do think there are acoustic effects of setting speakers out from the front wall similar to the acoustic effects of omnidirectional speakers and both effects can contribute to a vague sense of stage depth or spaciousness. (Absolutely, Mr. Bose). However, it is a phenomenon of monstrous complexity interfacing with the effects of mike placement in relation to the sound sources and room features in the recording environment as they appear in the recorded matter and has only begun to be explored by such people as Linkwitz and Duke LeJeune at Audiokinesis and probably many others I don't know about.

There are two overriding considerations which limit my concern about these kinds of psychoacoustic phenomena. The first is that unless the recording setup and the speaker setup are done to serve each other there will never be more than about one and half dozen recordings which accidentally achieve mastery of the complexities. The other is that number one means the issues debated in the late fifties early sixties between monaural devotees and advocates for the enthralling though imperfect complexities of stereo have never been resolved. Coupling this with the fact that there is no stereo effect in a concert all, especially not in the seats I can usually afford, means there is a good chance that for most people music would be at least equally accessible with good monaural recordings played over one good speaker. Maybe the reason Bose is so hated among mainstream and boutique audio professionals is that he identified and made a fortune marketing the one third rate psychoacoustic effect every stereo buyer is guaranteed to get.

[rusty jefferson]

....Based on my own experience, I would tend to agree - especially if the speakers have directional mid-highs (as is the case when using waveguides/horns).

Marco.[/COLOR]
I have to agree with you about the horns, but Mr Winer went a little far saying you have to have planars to introduce front wall reflections. Quality box speakers with low cabinet diffraction and a bipole tweeter or piezo ribbon tweeter have excellent directivity.

I have large format monitors and can create a very deep and wide soundstage, but it is limited. I can't get imaging behind the speaker cabinets themselves or beyond their width (without phase anomalies). It's a limitation of the speakers, not a complaint. :)



....In the end, there is no "right" or "wrong" way to enjoy music. To each their own.
Absolutely. I'm not flaming horn speakers. I'd like to hear the 1400 Arrays sometime.

[Robh3606]

Amused to Death used QSound Also one of my favorite set-up disks!

http://www.qsound.com/

Rob:)

[marco_gea]

I have large format monitors and can create a very deep and wide soundstage, but it is limited. I can't get imaging behind the speaker cabinets themselves or beyond their width (without phase anomalies). It's a limitation of the speakers, not a complaint. :)


OK - please do not take it the wrong way, but may I respectfully ask which large format monitors?
My suspicion is that the limitation resides mostly with their crossover, and not with their being large format, or soffit mounted...

[marco_gea]

If phase tricks can make a dog sound like it's barking from far away, then they must be replicating the phase events that occur naturally when a dog barks from far away and their use would not moot the subjective effect of a dog barking from far away when discerned with soffit mounted speakers and would not disprove anybody's notion that soffit mounted speakers can present stage depth.

I do think there are acoustic effects of setting speakers out from the front wall similar to the acoustic effects of omnidirectional speakers and both effects can contribute to a vague sense of stage depth or spaciousness. However, it is a phenomenon of monstrous complexity interfacing with the effects of mike placement in the recording environment as they appear in the recorded matter and has only begun to be explored by such people as whatsisname at Audiokinesis.

+1

[Ducatista47]

If there is any desire to have a setup/listening CD that eliminates artificial process-induced variables, try an MA Recordings disc. I have a bunch of them because I like the music but their being the highest fidelity (to the original performance) recordings I know of doesn't hurt.

It is a one-man label and Todd always records the same way. Acoustic performances in a live space, usually a hall or old church, so far no more than about eight musicians, two spectacular quality microphones fixed on a bar in the illustrated position or similar. Microphone preamp is a battery powered FET custom; cables directly to a digital recorder (currently a double DSD unit). No board, no mixing, no processing, and no editing. He monitors using Stax headphones. (Stax gave him the Omega prototype, he is well connected in the audiio world. Trust Todd's ears, everyone else does.) The purity of this process is not surprising; he lived in Japan for twenty-five years and you know their take on how things should be done. In any case, each recording has a good dose of reflections to work with, as well as a crystalline presentation of the instruments and voices.

82517

Notice that he found the best location for this Fortepiano in this Paris performance hall, and it was not the stage.

[rusty jefferson]

If phase tricks can make a dog sound like it's barking from far away, then they must be replicating the phase events that occur naturally when a dog barks from far away and their use would not moot the subjective effect of a dog barking from far away when discerned with soffit mounted speakers and would not disprove anybody's notion that soffit mounted speakers can present stage depth.....

Dave, I'm not implying that horns can't show depth, quite the contrary. The dog was recorded at a distance, however there is clearly a phase shift applied to it's insertion in the mix for effect, imho so it wasn't a good example of what Marco was getting at.



....I do think there are acoustic effects of setting speakers out from the front wall similar to the acoustic effects of omnidirectional speakers and both effects can contribute to a vague sense of stage depth or spaciousness. However, it is a phenomenon of monstrous complexity interfacing with the effects of mike placement in relation to the sound sources and room features in the recording environment as they appear in the recorded matter and has only begun to be explored by such people as Linkwitz and Duke LeJeune at Audiokinesis and probably many others I don't know about....

Well implemented I don't consider the effect vague, but rather surprisingly realistic. I agree with the rest of your statement, it is quite complex. I find it fascinating.


OK - please do not take it the wrong way, but may I respectfully ask which large format monitors?
My suspicion is that the limitation resides mostly with their crossover, and not with their being large format, or soffit mounted...
UREI 813C and 2245 subs. I won't be convinced easily that crossover changes would remedy the situation. The drivers are highly directive and not currently being soffit mounted makes for awful cabinet diffraction. I've heard numerous horn loaded speakers in normal sized home listening rooms and studios, and none can create the realism in imaging and imaging specificity as some of these more modern designs we've touched on. I haven't experienced it yet.


If there is any desire to have a setup/listening CD that eliminates artificial process-induced variables, try an MA Recordings disc. I have a bunch of them because I like the music but their being the highest fidelity (to the original performance) recordings I know of doesn't hurt.....

I continue to be appreciative of your introducing me to these recordings :)

[Ian Mackenzie]

Interesting discussion in the comments section of that page.

Mr. Ethan Winer said:
"Imaging has nothing to do with distance to the front wall unless you have dipole type speakers like Magnepans etc. Imaging is about mid and high frequencies, and normal "box" and tower type speakers send those frequencies forward, away from the front wall. The side wall distance could affect imaging, but only if the absorption isn't effective enough. I've seen people use diffusion at side-wall reflection points, and that too would affect imaging versus distance. Though IMO a normal width room should not have diffusion there because it's not as effective as absorption."

Based on my own experience, I would tend to agree - especially if the speakers have directional mid-highs (as is the case when using waveguides/horns).

Marco.


I think it’s logical when the speaker is toed in significantly or placed in the corners.

The sound can bounce at say 45-60 degrees diagonal from the front baffles off the front wall back towards the listener.

By either toe in or placement in the corners you modify the Hass effect

http://www.musicproductionglossary.com/what-is-haas-effect/

Obviously constant directivity or controlled directivity loudspeakers using wave guides can use these effects to advantage in creating a stereo image. Jbl has utilised this aspect of design since the introduction of Keeles Bi radial horn (2344a) and was later exploited in the 9500, 9800 and the a Everest systems.

Whereas the direct radiator systems or multi way systems using horns and cone drivers with un even polar response the effect is far less predictable or controlled.

Hence obtaining the sweet spot in blending the direct versus reflected sound with example the 4333-4343-4344 and 4345 is more difficult. They are significantly more complex than a two way woofer- wave guide design and there require a more stringent approach to adjustment much like a Ferrari. But setup carefully they bring out the best sonic virtues of each driver. The effect of hearing a snare drum on Miles Davis Kind of Blue vinyl album via a 2123H mid cone driver demonstrates it’s all about the drivers capacity to plant the snare not just as an image location in space but with realistic intensity and spatial clarity.

My point here is l believe a sufficiently good driver can create the same emotional engagement as a live instruument.
I do not believe magical trickery in the mix should be relied upon to hold the listeners interest. The logic being at the live event its the emotional connection with how an instrument is played that creates the interest and arousal of the senses.

On a DVD of a live musical event the optics connect with the auditory senses and localisation is complete. So how important is imaging?

I am not raining on the imaging parade but pointing out there the foundation of any attempt at imaging is the drivers.

Trying to find a woofer and a wave guide- compression driver to perform a miracle on paper won’t always bring home the prize.

[Ducatista47]

My point here is l believe a sufficiently good driver can create the same emotional engagement as a live instruument.
I do not believe magical trickery in the mix should be relied upon to hold the listeners interest. The logic being at the live event its the emotional connection with how an instrument is played that creates the interest and arousal of the senses.

On a DVD of a live musical event the optics connect with the auditory senses and localisation is complete. So how important is imaging?

.
I have been resisting reiterating my long ago thoughts about how over-fixated present-day listeners are with imaging and soundstage. I still won't, but encouraged by your remarks I will quote from that Omega speaker review I linked to. "One important thing to keep in mind, however, is that effects such as 'soundstage' and 'stereo imaging' are fun aspects of two-channel audio, but are unnecessary to the enjoyment of music."

Listen to a good single speaker mono system and close your eyes. There is an INCREDIBLE amount of spatial information in a single microphone recording. I'd say stereo added ten percent at most to the experience. If that sounds unlikely, imagine a listener who is deaf in one ear in a symphony - or any other - hall listening to a performance. What are they missing? Very, very little if anything. They still have a full and exact sense of further and closer, and of room reflections.

[Mitchco]

Great discussion on imaging!

This is a fun test to try if you can: https://www.audiocheck.net/audiotests_ledr.php Btw, audiocheck is a great site period.

Having worked in numerous studios, some with properly set up room acoustics and monitoring using guidelines from EBU (https://tech.ebu.ch/docs/tech/tech3276.pdf)and ITU (https://www.itu.int/dms_pubrec/itu-r/rec/bs/R-REC-BS.1116-3-201502-I!!PDF-E.pdf). it really helps to set up ones speakers in an equilateral triangle to best decode what was encoded at the studio, as that is the standard "stereo" configuration. Of course there are specs for early reflections/modal decay time/RT60, etc. that for sure have an influence.

Given the wavelengths involved some may go to lengths of trying to obtain a mirror image so the speakers/monitors are identical distance to the listener and each speaker from the front and side walls... Some of us use laser distance measurers to get the tolerances down to an 1/8th of an inch.

Some also use speaker and digital room correction (https://www.computeraudiophile.com/ca/ca-academy/%C2%A0integrating-subwoofers-with-stereo-mains-using-audiolense-r712/) to ensure the left and right frequency and timing response is as identical as possible like in the following measurements:

82518

82519


Having achieved that, then one is listening or decoding the stereo image as best as possible. I personally believe that speaker time alignment helps out as well. At this stage of setup, and taking into account time alignment, I would say it does not matter what the speakers/monitors are...

What does it sound like? Well, if one is playing a mono signal, it should sound like that it is coming from a point source positioned dead center in the phantom image at head height. Some folks say it feels like the sound is coming from inside the center of one's head. If you can achieve this, then one is pretty much guaranteed to be accurately reproducing whatever is stored on the media, whether analog or digital.

Listening to the LEDR recording with above configuration is accurately reproduced and fun to hear. I hope folks can listen to the LEDR recording.

For those interested in how the art is created, especially from a stereo imaging perspective, this is a great way to visualise it:
The Art of Mixing: https://www.youtube.com/watch?v=TEjOdqZFvhY

Hope everyone is having a wonderful Friday!

[Ian Mackenzie]

Hi Clark,

Thank you for the quote.

Many years ago l recall hearing the top model Dunlavy loudspeaker which was a well regarded for its imaging.

Below is a link to a review which l think fleshes out the topic nicely with all the why’s and wherefore’s.


https://www.stereophile.com/floorloudspeakers/99dun4/index.html

[Ducatista47]

Hi Clark,

Thank you for the quote.

Many years ago l recall hearing the top model Dunlavy loudspeaker which was a well regarded for its imaging.

Below is a link to a review which l think fleshes out the topic nicely with all the why’s and wherefore’s.


https://www.stereophile.com/floorloudspeakers/99dun4/index.html

Thank you, Ian. Nice link.

To assert that the spatial presentation of a system is worth nothing, or of little value, if the sonic fidelity is poor should be a given. But even in ponderous tomes of audiophile reviews like this example, it is rarely said or even implied. Quite refreshing to encounter.

The review was also unusual in giving us a break from the (usually) endless examples of obscure snippets from the reviewer's vinyl collection; much of the observations were based on test discs, which are less subjective and more quantifiable, and relatable when addressing spatial and frequency phenomenon.

Recognizing the calculus of accuracy versus being forgiving of normally encountered recording shortcomings was also nicely presented. My Stax 007 headphones are as revealing as it gets but they do have a slight frequency reproduction anomaly which renders them completely forgiving. When playing anything short of MA Recordings discs, it is needed to keep the whole experience wonderful every time.

[Ducatista47]

There is a doco on that album

It was all experimental with a lot of improvisation

I'm in love with a lot of Australian slang. I think my favorites are Hoons, chancer, and Shiela. (Hoodlums, a highly opportunistic person, and a pretty woman or any woman.)

[rusty jefferson]

Great discussion on imaging!

This is a fun test to try if you can: https://www.audiocheck.net/audiotests_ledr.php Btw, audiocheck is a great site period.....

......Listening to the LEDR recording with above configuration is accurately reproduced and fun to hear. I hope folks can listen to the LEDR recording.

Hey Mitch, Thanks for the interesting links.

I did download the LEDR test files and tried them on my (designed for home) listening system (not my UREIs) and they sound just as they should. The up/down and behind the speaker L/R pan tracks are completely free of the loudspeakers (no sense the sound is coming from them). These tracks used with others like the Mapping the Soundstage track mentioned earlier can be very informative and help set-up of a home system. I actually made a small adjustment (about 2") to my speakers placement while listening to the LEDR tracks, and it improved focus of the soundstage reproduction of the Stereophile track and also live recorded music. Well done.

For anyone who has been following this thread and isn't really clear about what they should be listening for, the above mentioned test tracks may help in setting up your speakers (within their limitations) to provide a better soundstage, along with all the other necessities mentioned earlier.



For those interested in how the art is created, especially from a stereo imaging perspective, this is a great way to visualise it:
The Art of Mixing: https://www.youtube.com/watch?v=TEjOdqZFvhY....

I'm still working my way through the videos, but thought it interesting the narrator made the point early on that his soffit mounted monitors can't reproduce an image wider than the speakers themselves, or higher (without manipulation), only lower than the speakers, because of the low frequency energy exciting the floor, as that has been part of this discussion. He did not mention whether they can image behind the cabinets, but I think it's safe to say not, only that he can create (or reproduce) a deep image between them.

[Mitchco]

Hi Jim,

Cool! The LEDR track is hard to reproduce properly, so kudos on getting your setup to work well with it. In addition to the LEDR test, there are a few more from audiocheck.net that are interesting: https://www.audiocheck.net/audiotests_stereophonicsound.php

I liked this example as well: http://buschmeier.org/bh/study/soundperception/

When I was still recording and mixing, we used the Haas effect (https://en.wikipedia.org/wiki/Precedence_effect) to give mono recorded vocals and instruments some width and depth, in addition to delay and reverb. It has an interesting effect. You can hear it (over headphones) in this music production demo: https://www.youtube.com/watch?v=UQOkSF8auFc&feature=youtu.be

While I enjoy large format studio monitors, I was not a big fan of soffit mounts in the control room. While the bass response is much improved, it was just weird looking up at the stereo image... :)

All good fun!

Cheers,
Mitch

[rusty jefferson]

Thanks Mitch, I'll check out those other test files as well.

Your YouTube link appears to be the same fellow Ian pointed us to in post #58 demonstrating the Haas Effect by adding time delay while mixing.

[Mitchco]

Jim, cool! I hope you enjoy those. And yes it is indeed the same person Ian pointed out in his post. Great minds think alike...? :) Cheers!

[rusty jefferson]

I was thinking about starting a new thread as a way to move a divergent discussion from this thread (https://www.audioheritage.org/vbulletin/showthread.php?36661-UREI-Speaker-discussions&p=446791#post446791) about UREIs when I remembered Mr Widget started this thread for the same reason several years ago. It's worth a re-read.


Odd that this discussion comes up now. My wife made her way to the basement workshop last night and sat in the listening chair while I was playing the Kind Of Blue Deluxe 50th Anniversary Collector's Edition and the first thing she asked was if all four pairs were playing, when in fact the only ones playing were the 250ti on the ends. Then she commented on how distinct each individual instrument was and how everything was placed so well across the room. She doesn't know the term "soundstage" but she certainly gets it. Not sure why it would take a 2-way with a wave-guide to improve this but I'm pretty pleased with the way the massive 4-way pyramid does it—without a modern wave-guide. At one point I toyed with getting a 1400 Array. Maybe that needs to be my next acquisition just to see what it can do. At the time I got sidetracked by the 4345 for the same money. :hmm:
Phil, As mentioned in the first couple posts of this thread there are some divergent ideas of the definition of imaging vs soundstage. The image is of course the phantom image created between the loudspeakers and in audiophile circles, part of the soundstage. In most studio and typical home listening situations the image is between the two speakers and on plane with the two speakers. Voices and instruments can be specifically placed or heard anywhere in that image area or simply massed together without specificity in the image.

In audiophile circles the soundstage is the re-creation of a live recorded event in an acoustic space usually made with two or three microphones. When played back on speakers designed to re-create the performance in a room that can support it, the image moves from between the speakers and on plane with them to behind the speakers and expanding to the width of the room and with depth that can appear to be 30 or 40 feet deep. Also, there will be absolutely no sound audible coming from the speakers, all of the sound seeming to come from the soundstage behind them. Speakers that image well (studio recordings) will not usually re-create the natural soundstage from a live recording, and speakers that re-create the soundstage well will still create the center image between the speakers (studio recordings) but usually not as well focused as the former.

Speakers with well controlled directivity as Mr Widget described in the UREI thread image well. Speakers with wide and matched dispersion at crossover points tend to re-create the soundstage well because of their almost omnidirectional dispersion. What comes into play for the latter type is the listening room. Careful treatment is needed to not have early arrival reflections, but rather late arrival of reflections primarily through diffusion of the reflections rather than absorption of the reflections as in the studio setting. What all this is getting to is your 250ti are more of the wide dispersion type and the speakers Mr Widget is using (as am I) are the controlled directivity type.

Here's a link to a video of the speaker I'm currently using where the builder demonstrates the same drivers in the same box, the only difference being the baffle. One controlled directivity and one wide dispersion. Note the horizontal polar plots he shows of the two side by side a few minutes in. The speaker on the left could be set up in an appropriate room to create a larger soundstage than the speaker on the right, though the one on the right will overcome many typical room problems and fit into a much wider variety of rooms better (the reason I'm using them) and provide spot on imaging (between the speakers).
https://youtu.be/f6S2V9D9_08?feature=shared

I haven't experimented with 250tis but if you have time and interest, that large space you're in might show you what their potential for creating a large soundstage is. Read up on the Cardas rule of thirds technique for set up and experiment. Experiencing that large, deep soundstage without the ability to tell where the sound is coming from can draw you into a performance like nothing else. It is hard to achieve though. If you're traveling through the DC area in retirement I have a few friends who have achieved it with their systems who would be happy to have you for a visit.

[Mr. Widget]

Thanks for posting this here. I had completely forgotten about my posts and this thread.

For me personally it is interesting to see how my viewpoint has evolved over time as I have had more experiences in different rooms and with different systems. I would say I still agree with much that I posted earlier in this thread, but I have learned a lot over the last 5 plus years and not everything I believed then do I still have confidence in. (It would be interesting and probably cringe worthy to go back and read some of my posts from 20 years ago.)

Along those lines, in my initial post on this thread I elaborate on the electronics suggesting that they are potentially significant in the imaging of the system. My current understanding is that the electronics will have minimal if any effect. I should have spent more time discussing the room and layout.

Regarding Phil's comments on the imaging/soundstage of the 250Tis his description is more in line with how my Project Widgets portray music including Kind Of Blue. As a reminder: https://www.audioheritage.org/vbulletin/showthread.php?41842-Project-Widget

These speakers create a deep and wide image/soundstage. The TAD TH4003 horns have controlled dispersion that is very tight vertically and fairly tight horizontally and below them there is a fairly flat profiled 10" driver covering most of the rest of the spectrum. These speakers place images across the space between the speakers and even beyond. (my current understanding is that this is a function of reflections from the side walls) The image is stable and layered, but it is also more diffuse when compared to the 1400 Arrays that had previously been set up in similar locations in the same room. The compact Meyer Sound "point source" speakers as deployed in my HT are a significant step further in this regard. In that system (room and speaker position within the room) certain recordings sound like a surround sound recording and a center panned source is completely detached from the left and right speakers. My DIY TADs have a more defined image than say my previous Everests did, but that could be the room as much as the speakers. As I have gained experience, I have learned more and more how important the room and placement within the room truly is. I had previously compared the same 1400 Arrays with the Everests in my old listening room and there too the 1400 Arrays had a more focused image than the Everests so there is a consistency there.

So then, how important is imaging? I enjoy the heck out of both of my systems... one super focused and one fairly diffuse. I have never heard a live performance that sounded anything like audiophile imaging, but it is fun. Then again, a well recorded live recording played back through the more diffuse TAD system sounds pretty darned close to a live experience.


Widget

[BMWCCA]

Can we just re-name this whole group The Slippery Slope?
Or the whole hobby.

Fun, but I had to take a break to work on a car today. Hopefully finished soon in time to take my wife to a live Jazz performance this evening so we can compare.

https://robertjospe.com/2024/02/charlottesville-va-feb-02-wtju-offbeat-roadhouse/

The leader is a friend and, after many years of preaching, also a customer. His first BMW and he's had it now for over 5-years and has enjoyed his travels all over the country more than ever before!

[Robh3606]

Hello Rusty

Thanks for revisiting this. Interesting how people define Soundstage and imaging. I guess I have my own definition based on my own experiences. To me soundstage is the sound field created by the speakers and imaging is what happens within it.

I don't see a pair for speakers doing true envelopment. I see that as a multichannel experience not stereo. Even with a good multichannel set-up as close as it can sometimes sound it is clearly artificial,

I look at Live music and stereo/multichannel as two independent and separate pursuits. They are not alike and don't sound that way. Al least to me although I thoroughly enjoy both.

I am a CD advocate and most of my systems are CD.

I have seen repeated so many times that horns and waveguides don't image as well as cones and domes and find that to be decidedly false. To me this all comes from the older classic horn systems

Nice speakers!

Rob :)

[rusty jefferson]

.....I have seen repeated so many times that horns and waveguides don't image as well as cones and domes and find that to be decidedly false. To me this all comes from the older classic horn systems

Nice speakers!

Rob :)
Rob, I've not heard that trope when it comes to imaging as I just described how we use the term amongst our group of friends, but rather their poor soundstaging abilities based on how we use that term as I just described it. Most of my listening friends are non-horn audiophiles who listen primarily to classical live recordings. That huge soundstage laid out behind the speakers is really important to their experience and they're using wide dispersion speakers in dedicated rooms following the rule of thirds mentioned before. Horn speakers with good controlled directivity image great!

I think they would say you can't have a soundstage without an image but if the image is just between the speakers that's not a good soundstage. Don't know if that makes sense to everybody?

[Robh3606]

I think they would say you can't have a soundstage without an image but if the image is just between the speakers that's not a good soundstage. Don't know if that makes sense to everybody?

That makes sense to me and appearing to going out beyond the edge of the speaker pair and sensing depth as opposed to "flat". You also have stability where the "image" doesn't shift as your head moves or sit stand.

A simple example vocals up front band behind for depth or at least drums behind. For a large orchestral piece the choir would be behind the orchestra and a vocal soloist up front.

That make sense??

Rob :)

[Mr. Widget]

Does the magic effect work outdoors in a non reflective space? It sounds as if what wraps around the speaker and is reflected from behind is an important part of the equation?

I should take my best point sources outside and compare their performance in open space.
Did you ever try this out? It would be a very useful experiment to see how a speaker's imaging/soundstage changes when the room is removed.


Widget

[Robh3606]

Did you ever try this out? It would be a very useful experiment to see how a speaker's imaging/soundstage changes when the room is removed.


Widget

Hello Widget

I have had a stereo pair outside and the sound is much more like separate sources. I also have a stereo pair installed on edges of my shed with a subwoofer inside. They will image if you are between them but the sound field isn't anywhere near as cohesive as it is indoors.

As you add distance it becomes more wall of sound. There is no sense of envelopment that I can hear. These are relatively low cost outdoor speakers. 6" drivers 1" tweeter. They sound really good but different compared to indoors IMHO.

Rob :)

[jpw retired]

Thanks for posting this here. I had completely forgotten about my posts and this thread.

For me personally it is interesting to see how my viewpoint has evolved over time as I have had more experiences in different rooms and with different systems. I would say I still agree with much that I posted earlier in this thread, but I have learned a lot over the last 5 plus years and not everything I believed then do I still have confidence in. (It would be interesting and probably cringe worthy to go back and read some of my posts from 20 years ago.)

Along those lines, in my initial post on this thread I elaborate on the electronics suggesting that they are potentially significant in the imaging of the system. My current understanding is that the electronics will have minimal if any effect. I should have spent more time discussing the room and layout.

Regarding Phil's comments on the imaging/soundstage of the 250Tis his description is more in line with how my Project Widgets portray music including Kind Of Blue. As a reminder: https://www.audioheritage.org/vbulletin/showthread.php?41842-Project-Widget

These speakers create a deep and wide image/soundstage. The TAD TH4003 horns have controlled dispersion that is very tight vertically and fairly tight horizontally and below them there is a fairly flat profiled 10" driver covering most of the rest of the spectrum. These speakers place images across the space between the speakers and even beyond. (my current understanding is that this is a function of reflections from the side walls) The image is stable and layered, but it is also more diffuse when compared to the 1400 Arrays that had previously been set up in similar locations in the same room. The compact Meyer Sound "point source" speakers as deployed in my HT are a significant step further in this regard. In that system (room and speaker position within the room) certain recordings sound like a surround sound recording and a center panned source is completely detached from the left and right speakers. My DIY TADs have a more defined image than say my previous Everests did, but that could be the room as much as the speakers. As I have gained experience, I have learned more and more how important the room and placement within the room truly is. I had previously compared the same 1400 Arrays with the Everests in my old listening room and there too the 1400 Arrays had a more focused image than the Everests so there is a consistency there.

So then, how important is imaging? I enjoy the heck out of both of my systems... one super focused and one fairly diffuse. I have never heard a live performance that sounded anything like audiophile imaging, but it is fun. Then again, a well recorded live recording played back through the more diffuse TAD system sounds pretty darned close to a live experience.


Widget

I completely agree that I seldom, if ever, have heard a live performance that sounds like audiophile imaging.

Although there are many large format speakers I haven't heard my general experience has been that they don't offer the "holographic imaging" (for lack of a better term) that many audiophiles value.

Narrow baffled speakers with petite drivers that do offer that kind of imaging sound like toys compared to large format speakers especially when it comes to dynamics.

To my audiophile friends who generally disdain horns, I like to point out that wide dynamics are undeniably a part of live music while "holographic imaging" is not. When they disagree I have them over to hear my band.

[Mr. Widget]

I have had a stereo pair outside and the sound is much more like separate sources. I also have a stereo pair installed on edges of my shed with a subwoofer inside. They will image if you are between them but the sound field isn't anywhere near as cohesive as it is indoors.In this context, what does cohesive mean?


As you add distance it becomes more wall of sound. There is no sense of envelopment that I can hear. These are relatively low cost outdoor speakers. 6" drivers 1" tweeter. They sound really good but different compared to indoors IMHO.
This makes sense. Since there are no reflections to create a larger sense of soundstage.


To my audiophile friends who generally disdain horns, I like to point out that wide dynamics are undeniably a part of live music while "holographic imaging" is not.Yep... I guess it comes down to what do you want?

Personally I admit that I get a kick out of the audiophile image thing, but I also like live music to sound like it's alive! I agree that large format compression drivers and horns tend to do that best. I think cone size matters too.

My little Meyer speakers have a 3" compression driver in-between a pair of 5" LF drivers. They are reasonably dynamic, but not in the league of a larger JBL or Altec. But then again, they will do the audiophile image thing better than anything else I have heard. Glad that so far I can still have multiple systems, someday downsizing may have to happen... that will be a sad day.


Widget

[Robh3606]

In this context, what does cohesive mean?

This makes sense. Since there are no reflections to create a larger sense of soundstage.

Yep... I guess it comes down to what do you want?

Personally I admit that I get a kick out of the audiophile image thing, but I also like live music to sound like it's alive! I agree that large format compression drivers and horns tend to do that best. I think cone size matters too.

My little Meyer speakers have a 3" compression driver in-between a pair of 5" LF drivers. They are reasonably dynamic, but not in the league of a larger JBL or Altec. But then again, they will do the audiophile image thing better than anything else I have heard. Glad that so far I can still have multiple systems, someday downsizing may have to happen... that will be a sad day.


Widget

Hello Widget

What does cohesive mean. Hard to describe even though they image it's more obvious that it is from 2 sources?? Not sure how else to say it. It's much easier to move left/right and it falls apart. You really have to depend on precedence as there is no other thing working for you?? Hope that makes some kind of sense. Their is nothing else to reinforce the image???? Your are essentially in free space.

Rob.:)

[Ian Mackenzie]

Hi Rusty,

Thanks for re visiting this thread. Looking back l do recall the Dunlavy loudspeakers which were well know for their imaging. An LHS member over here has a pair of the large Sovereigns. I must have another listen

Attached is a similar model.

[BMWCCA]

Hi Rusty,

Thanks for re visiting this thread. Looking back l do recall the Dunlavy loudspeakers which were well know for their imaging. An LHS member over here has a pair of the large Sovereigns. I must have another listen As a long-time JBL owner, something about all that Dunlavy symmetry is upsetting my equilibrium. :spin:

[Ian Mackenzie]

As a long-time JBL owner, something about all that Dunlavy symmetry is upsetting my equilibrium. :spin:

The L250ti does similar things. Just packaged differently. Neither is an oil painting. Nor the Project Array for that matter. Had JBL done what ESS did with the AMT1 it might have been more accepted.

[Ian Mackenzie]

Here is a question?

Who thinks Dipole loudspeakers image better than a conventional box loudspeaker?

[BMWCCA]

The L250ti does similar things. Just packaged differently. Neither is an oil painting. Nor the Project Array for that matter. Had JBL done what ESS did with the AMT1 it might have been more accepted.

It was humor!
I've found the 250 versions to be very off-putting in their weird asymmetry since they first came out. Looking at them while listening to them reminds me of when I was in college laying on a water-bed, drunk, trying to steady myself with one foot on the ground. The 250s always look like they're about to tip over. Like the leaning tower of Pisa to me. Even worse when I see them swapped left to right!
:blink: :cheers:

[rusty jefferson]

Here is a question?

Who thinks Dipole loudspeakers image better than a conventional box loudspeaker?
Well, now that depends on what the definition of 'image' is. Based on what I spelled out that we use, no. The best imaging speakers are point source and/or controlled directivity. Dipoles will create a big soundstage, but diffuse and inaccurate, and the imaging tends to suffer with inaccuracies also, like a vocalist image that fills the whole area between the speakers rather than being pinpoint.

[Mr. Widget]

Well, now that depends on what the definition of 'image' is...Exactly...

Dr. Amar Bose thought he found the holy grail when he came up with the 901. I don't think he was entirely wrong, but he didn't produce a system that will create the type of "image" that I am looking for. That said, if I stumbled upon a pair of 901s, I'd love to bring them home and play with them.


Widget

[Mr. Widget]

Here is a question?

Who thinks Dipole loudspeakers image better than a conventional box loudspeaker?Maggies and many electrostatic panel based systems are dipoles. They image... but not like a holographic mini monitor.

There is a reason why so many designs exist and why so many DIYers are certain they have invented the wheel. All of these approaches and designs are far from perfect and they all offer something to enjoy.


Widget

[rusty jefferson]

It was humor!
I've found the 250 versions to be very off-putting in their weird asymmetry since they first came out...
I think it's really an ahead of its time design with the low diffraction cabinet and asymmetrical shape. I never had a place with enough space to set up a pair. They really should be set up with a rule of thirds arrangement. Also, I hate those Titanium dome tweeters. I know it was the best available at the time, but it would be worth modding a pair with a more modern midrange and BE tweeter. :-)

[Ian Mackenzie]

Thanks Widget.

I recall some box loudspeakers had a tweeter in the rear to create a limited dipole effect.

Of course the Bose 901 had a cult following too.

[BMWCCA]

Thanks Widget.

I recall some box loudspeakers had a tweeter in the rear to create a limited dipole effect.

Of course the Bose 901 had a cult following too.Which reminds me of my fondness for the lowly DCM TimeFrame 600 with two-rear-firing tweeters and one coaxially mounted over one front woofer. It is really quite a surprising presentation for such a humble package.

[jpw retired]

Hi Rusty,

Thanks for re visiting this thread. Looking back l do recall the Dunlavy loudspeakers which were well know for their imaging. An LHS member over here has a pair of the large Sovereigns. I must have another listen

Attached is a similar model.

My store, Audio Video Logic, was the largest US dealer of Dunlavy speakers from 1992 until the early 2000's when they closed. I knew John (and his wife Joan) personally having made many trips to Colorado Springs to his manufacturing facility where he was always proud to show off his large anechoic chamber as well as explain his design philosophy.

Hie would place his speakers far apart, almost in your peripheral vision, to prove how well his speakers could focus a center image. This provided a very wide presentation, definitely row one.

Dunlavy and JBL have gone down in time as my two favorite speaker brands. General speaking they were two different design philosophies but each the best at what they were aiming for.

[Ian Mackenzie]

It’s interesting that such attempts at imaging cross into industrial design with disastrous consequences. The dilemma (except for the diyer).

[jpw retired]

Here is a question?

Who thinks Dipole loudspeakers image better than a conventional box loudspeaker?

Speaking of dipole panel speakers like Magnepan's or Martin Logans, they certainly image WAY differently. On some kinds of instruments or vocals they have rather entertaining amounts of spatial distortion. One benefit is that they seldom sound small.

They do share one characteristic with large format speakers in that both exhibit what I call low surface loudness where the SPL generated is spread out over large diaphragms. This probably works against pin point imaging if that's your bag.

[Ian Mackenzie]

Hi John,

Thanks for sharing your association with Dunlavy. He actually set up shop over here in South Australia for a while. Alex Encel sold a lot of these massive monoliths through his retail business Encel Stereo in Bridge Road Richmond an inner suburb of Melbourne.

For those interested in the technical side Dunlavy was obsessed with time domain behaviour of his loudspeakers. Any reference to the spatial qualities of a loudspeaker is a heads up the designer has done his homework.

It’s scientific language but worth a read if you’re trying to join the dots …

https://www.sciencedirect.com/topics/medicine-and-dentistry/sound-localization#:~:text=Localizing%20sounds%20in%20th e%20horizontal,louder%20than%20the%20left%20ear.

Of course JBL’s LSR range was all over that.

If you then come full circle and do some listening it’s those fragile transients that if blurred cause all the fuss. I say fragile because loudspeakers tend to do a good job of screwing up these vital sounds to the detriment of imaging. But we listen too them anyway

[Ian Mackenzie]

Again if you’re curious this is a playbook of descriptors used by a loudspeaker designer to assess a design subjectively. It’s quite detailed (sorry for the pun) so grab a coffee.

The start

After all this technical tediousness, it is time to finally move on to the section, which I think is the most important of all, because no measurements, graphs, diagrams and pictures can give a complete picture of the sound of the system. Of course, it is possible to draw some conclusions and predict general trends, but no more.

I will try, as much as I can, to formulate my subjective impressions about the sound of the speakers, relying on generally recognized definitions of sound characteristics. After all, auditory impressions are the final product consumed by our brain.

Soundstage (sound picture)

The scale of the sound picture is the first thing that impresses from the first notes - it is simply huge. The entire sound cloud is located far behind the speakers, which simply dissolve into space. The sound is absolutely not tied to the speakers, you instantly forget about them and a truly living musical canvas unfolds before your eyes without boundaries in width and depth.

The height of the sound picture is quite realistic, there is no feeling that you are watching what is happening on the stage through a narrow slit.

Localization and focusing are excellent, the contours of sound images are very precise and clearly visible, no blurring. In large symphony orchestras, all the instruments are in their places, no one climbs forward and does not try to change with anyone, which is extremely important when listening to classical music.

The depth (echeloning) with the second version of the crossover is excellent, perfectly felt separation of instruments in space. Three-dimensionality of the sound canvas and sonic perspective are felt from the first notes. The sound images are well rendered, there is an air between them. With the first version of the crossover, such 3D sensations are less pronounced.

Transparency is very high over the entire frequency range. The impression of crystal clarity and purity of the sound canvas, especially in the first version of the crossover.

The concert hall atmosphere rendering and reverberation are quite good.

The physicality, fullness and relief of sound images are at an average level and better in the second version of the crossover.

Dynamic characteristics

Microdynamics - the dynamic nuances of all subtle and quiet details are excellent. The high resolution and low inertia of the tweeter together with very low mechanical losses in the midwoofer do their job.
Macrodynamics - thanks to the very low distortion of both drivers, the loudspeaker has an explosive character without a hint of overload. A noticeable compression, maybe only at high sound pressure levels. The sound attack worked out just lightning fast with precise temporal contours. No sluggishness and blurry fronts, everything is very lively and realistic in time.

Timbre
The tonal balance is close to neutral, without any tints. Neither dry nor wet, neither warm nor cold.

The overtonal saturation is at a natural level, not overstated toward excessive colorfulness and not understated toward sterility.

The bass for such micro-speakers is simply amazing - deep, dense, dynamic, weighty and solid. Tight, like a tightly stretched rope and beats like a sledgehammer. It's low-fat and well-structured.

The drums are very dynamic. The double bass and cello are as alive, well readable, with many shades (halftones). The bass character strongly depends on the type of enclosure setting which I described before.

The grand piano sounds with excellent attack, energy and well-defined hammer strikes. The bass guitar with a well-read relief.

The mids are very natural, detailed, transparent and dynamic.

High frequencies are entirely due to the nature of the beryllium tweeter. Very realistic presentation, very fast, with an explosive character, no sluggishness and blurring of the sound attack. Not harsh, not annoying, not tiring.

The clanging and ringing of the percussion are similar to the real ones, only the size of the instruments is smaller. You won't hear the lush, colorful timbre that silk tweeters are known for, but the timbre and percussion attack are conveyed very correctly, therefore, metal cymbals sound very clear, transparent and clear, just like real metal cymbals, and not smeared and dirty, like silk tweeters do.

The right side of the piano keyboard sounds with the first version of the crossover, maybe a little brighter than I would have liked, but everything is within the limits of what is allowed, without glazing.

The nylon strings of classical guitars sound quite natural, while the metal strings of acoustic guitars sound sharp and juicy.

The harpsichord, a very complex instrument, sounds like a harpsichord, with excellent sharpness and resolution of all sounds.

Brass winds sounds with real power, just like the metal winds, not the wood ones.

Orchestral violin string groups sound detailed, smooth and exciting, with high resolution.

Auxiliary characteristics
The resolution is very high. The loudspeakers allow you to view the musical material in the smallest detail.

Purity - very low distortion, no any extraneous sounds and distortions at any volume level.

Engagement - above average. You are not just watching the process from the outside, but even a little involved in it.

[jpw retired]

Hi John,

Thanks for sharing your association with Dunlavy. He actually set up shop over here in South Australia for a while. Alex Encel sold a lot of these massive monoliths through his retail business Encel Stereo in Bridge Road Richmond an inner suburb of Melbourne.

For those interested in the technical side Dunlavy was obsessed with time domain behaviour of his loudspeakers. Any reference to the spatial qualities of a loudspeaker is a heads up the designer has done his homework.

It’s scientific language but worth a read if you’re trying to join the dots …

https://www.sciencedirect.com/topics/medicine-and-dentistry/sound-localization#:~:text=Localizing%20sounds%20in%20th e%20horizontal,louder%20than%20the%20left%20ear.

Of course JBL’s LSR range was all over that.

If you then come full circle and do some listening it’s those fragile transients that if blurred cause all the fuss. I say fragile because loudspeakers tend to do a good job of screwing up these vital sounds to the detriment of imaging. But we listen too them anyway

IIRC In the late 70's John got a grant of some sort from the Australian government for research into speaker design. I believe his facility was located in or near Adelaide and of course this resulted in the Duntech brand being launched. John was always more interested and better at running a speaker laboratory than a manufacturing facility.

Prior to this he had worked for the US government in some capacity designing antennae's for which a number of patents were issued. I don't think he got a dime from them though. He once mentioned to me that his speakers emulated one of his antennae designs.

I remember one night in particular visiting him in Colorado Springs. He took me and my wife and his wife Joan gambling to a town in the mountains just west of Colorado Springs. I was the big winner, $165.00! Then we went back to his house where we drank port wine until the wee hours of the morning. I had a 11 hour drive later that day back to Iowa nursing a terrible hangover. I had never had port before and never will again!

[rusty jefferson]

.
...Soundstage (sound picture)

The scale of the sound picture is the first thing that impresses from the first notes - it is simply huge. The entire sound cloud is located far behind the speakers, which simply dissolve into space. The sound is absolutely not tied to the speakers, you instantly forget about them and a truly living musical canvas unfolds before your eyes without boundaries in width and depth.

The height of the sound picture is quite realistic, there is no feeling that you are watching what is happening on the stage through a narrow slit.

Localization and focusing are excellent, the contours of sound images are very precise and clearly visible, no blurring. In large symphony orchestras, all the instruments are in their places, no one climbs forward and does not try to change with anyone, which is extremely important when listening to classical music.

...perfectly felt separation of instruments in space. Three-dimensionality of the sound canvas and sonic perspective are felt from the first notes. The sound images are well rendered, there is an air between them....

Transparency is very high over the entire frequency range......
That's how we'd describe it and separate it from simply 'the image' that pretty much any pair of speakers will create between them. Achieving that level of transparency and realism is difficult and of course not everyone's cup of tea. :-)

[Ian Mackenzie]

I skipped one important stage

The recording process.

The attachment is only a simplified graphic that most can relate to.

(If you have OCD just deal with it)

Unless the recording is done with the artist(s) in one place at one time then imho any attempt at true imaging is not organic. It’s what the producer does with mic setup and at the console and with various effects processors. It’s interesting that raw mic recordings can be a bit dry and uninteresting to the general public. But at the venue it can be a revelation.

So is the recording the weak link in the imaging stakes?

Say what think. There’s no right or wrong answer.

I personally leave it to the producer because only they know the meaning that the artist wants to convey in the recording on the day. The song or tune belongs to them after all.

An example of this is here at number 4

https://www.cnbc.com/2011/07/18/Top-Singles-Produced-by-Quincy-Jones.html

4. We Are the World

In 1985, Lionel Richie approached Jones with the idea of an all-star concert tour to benefit African famine relief. Jones had another thought. “I said, ‘Why aren’t we doing records instead? A tour can be a nightmare.’ So we decided to do a record,” Jones told CNBC.

Jones managed to get over 40 of the US top artists to gather after a TV presentation at the A&M studios.

The session went till the next morning. The result is a stunning recording that is the subject of a documentary on Netflix. Jones captures the best that each performer can sing at a memorable session.

[Ian Mackenzie]

That's how we'd describe it and separate it from simply 'the image' that pretty much any pair of speakers will create between them. Achieving that level of transparency and realism is difficult and of course not everyone's cup of tea. :-)

This was actually a small monitor style loudspeaker system.

https://hificompass.com/en/projects/2-way-systems/puribliss-4p25b#4

The thing is how do you calibrate or measure good from bad? There are very few standards for measurement of a loudspeaker let alone listening to one. So I think separating it out up helps to focus on each aspect of what your hearing.

With the measurements now available (and accessible) to the diyer the opportunity has arrived to tinker, test and learn at home. It needn’t cost a bomb either with some well informed choices.

[toddalin]

Experiencing that large, deep soundstage without the ability to tell where the sound is coming from can draw you into a performance like nothing else. It is hard to achieve though. If you're traveling through the DC area in retirement I have a few friends who have achieved it with their systems who would be happy to have you for a visit.

I have achieved this with the Mermans and anyone who visits So Cal is welcome to come by and hear/experience a soundstage and image that is totally immersive and unbelievable. This is nothing like my Super Big Reds (Altec 604-E2/aux Utah 15", all triamped). One of the AK gents came by after listening to a $100,000+ system and said the Mermans had better soundstage and imaging and he was totally blown away!

I think that time alignment plays a large part so if horns are involved, the signal should be "processed" for time alignment and this is why the older horns don't image well. Newer horns are more shallow and more of a "wave guide" and I think this is where the difference lies.

BTW, in my view "soundstage" is what is happening between/beyond the speakers and can be created artifically in a studio through mixing, or captured from a live performance. And it doesn't need to be a realistic approach. If the engineer wants to spread the drum kit from the left wall of the room to the right wall of the room, that is his perogative and is still "soundstage".

[Mr. Widget]

BTW, in my view "soundstage" is what is happening between/beyond the speakers and can be created artifically in a studio through mixing, or captured from a live performance. And it doesn't need to be a realistic approach. If the engineer wants to spread the drum kit from the left wall of the room to the right wall of the room, that is his perogative and is still "soundstage".I think we all agree and that is universally accepted as the definition. Where we head all over the map is when we describe a good, or solid, or realistic, or any particular type of sound stage.



I have achieved this with the Mermans and anyone who visits So Cal is welcome to come by and hear/experience a soundstage and image that is totally immersive and unbelievable. This is nothing like my Super Big Reds (Altec 604-E2/aux Utah 15", all triamped). One of the AK gents came by after listening to a $100,000+ system and said the Mermans had better soundstage and imaging and he was totally blown away!Not to take away from your speakers which I am sure are fine speakers, from the photos you have posted in the past, it is my understanding that your room is quite large so the arrival time of the primary and secondary reflections will be delayed longer than in a smaller room. This helps our brains create a better stereophonic illusion. I would bet this is a significant contribution to their exemplary performance.


I think that time alignment plays a large part so if horns are involved, the signal should be "processed" for time alignment and this is why the older horns don't image well. Newer horns are more shallow and more of a "wave guide" and I think this is where the difference lies.
The time alignment benefit is possible, but I think the wave guide or better directivity control makes the lion share of what is required for "better" imaging within the sound stage.

When we were working on Project May with the H9800 horn and MTM 1500ALs back in 2004/2005 we worked on a passive network and also a digital multi-amped version using the original DEQX 2 by 6 preamp. Those speakers never really worked in the sound stage department. We were working in a very large room with acoustical treatment and the image was alway extremely flat and planar with zero stage depth. Time aligning the speakers affected the frequency response and therefore the sound, but it had zero effect on the imaging/sound stage.



Widget

PS: Hard to believe that was 20 years ago!

[toddalin]

I am sure that the room has a large impact on the image with the "reverse" angle ceiling reflecting sound back to the front wall increasing perceived "depth" but also adding it's own "ambience." Room is 26' long x 16' deep, 7.5' - 16' high. The speakers are ~7.5' apart and ~10.5' from the sweet spot.

The Altecs are on the 16' wall and I pull a chair and automan infront of the sofa cushion to listen to them.

I've spent years working on the Mermans and it really wasn't until I got the crossovers just so, got the Heils to where they are, and time aligned all of the drivers, based on RTA readings at the sweet spot, that the imaging got really good. It just sort of happened and now it is "what it is all about." You can hear when the engineer so much as touches a pan pot.

https://cimg0.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/2000x1333/80-dsc_0007_69409beeed87064ad242cebae7e2a858107c6978. jpg

[Ian Mackenzie]

Hi Mr Widget,

Your insights provide a possibility to explore a further understanding.

I think most of us have experienced the head in a vice situation at some point. The function of a CD horn is to project a uniform off axis output over a defined area.

Given your experience with different rooms how does that impact on the sound stage in terms of moving the listening position?

[Robh3606]

The Heil's I find can give you quite a bit latitude to experiment with image focus and the ratio of direct to reflected energy. I started a thread a while back about the topic of absorbing the back-wave the effect of image focus and imaging in general.

You can run them as full dipoles and get a very expansive sound field that lacked focus or experiment with absorbing the the back-wave and trying to find suitable balance that would make the sound field smaller but also focus the imaging and make it less diffuse.

It's quite a bit of fun to be able to change a speakers "signature" as easily and as quickly. All you had to do was to add of remove the fiberglass batting from behind the driver and it was like two different systems.

Rob :)

[toddalin]

I had previously been removing the back wave and actually started noticing the increase in "pin-point" imaging when I put the rear half-round in the Heil flattening it's response from ~3kHz to above audibility and "steepening" the 2nd order slope on the 2251J. Though the 2251/Heil are crossover over at ~2.5kHz, the rise in response at ~3-4kHz in the 2251 manifests itself either as constructive or destructive when the two drivers combine. Combined, they create a peak through this range when in phase and a dip if out of phase. The peak is much worse than the dip and steep slopes on both drivers mitigate the problems.

BTW, you need to be careful what you put back there. When I had a sheet of the adhesive-backed noise mat back there, it created a reflection that made a really nasty dip at ~5KHz in the Heil's response. This is when I realized that changes made behind the driver have a direct impact on what comes out the front.

[Robh3606]

I had previously been removing the back wave and actually started noticing the increase in "pin-point" imaging when I put the rear half-round in the Heil flattening it's response from ~3kHz to above audibility and "steepening" the 2nd order slope on the 2251J. Though the 2251/Heil are crossover over at ~2.5kHz, the rise in response at ~3-4kHz in the 2251 manifests itself either as constructive or destructive when the two drivers combine. Combined, they create a peak through this range when in phase and a dip if out of phase. The peak is much worse than the dip and steep slopes on both drivers mitigate the problems.

BTW, you need to be careful what you put back there. When I had a sheet of the adhesive-backed noise mat back there, it created a reflection that made a really nasty dip at ~5KHz in the Heil's response. This is when I realized that changes made behind the driver have a direct impact on what comes out the front.

Hello Toddalin

I agree about what you put behind them. I purposely stuck to either felt of fiberglass. I was concerned as well about reflections back through the membrane. I was considering a small sub enclosure but decided against it. Fun drivers!

Rob :)

[Ian Mackenzie]

Hi Todd,

What distance from the side / rear wall worked best for you?

[Mr. Widget]

I am sure that the room has a large impact on the image with the "reverse" angle ceiling reflecting sound back to the front wall increasing perceived "depth" but also adding it's own "ambience." Room is 26' long x 16' deep, 7.5' - 16' high. The speakers are ~7.5' apart and ~10.5' from the sweet spot.




Hi Todd,

What distance from the side / rear wall worked best for you?
Yes, Todd if you could give us a simple sketch of teh layout with a couple of dimensions it would very cool to better understand your room.

Widget

[Mr. Widget]

I had previously been removing the back wave and actually started noticing the increase in "pin-point" imaging when I put the rear half-round in the Heil flattening it's response from ~3kHz to above audibility and "steepening" the 2nd order slope on the 2251J. Though the 2251/Heil are crossover over at ~2.5kHz, the rise in response at ~3-4kHz in the 2251 manifests itself either as constructive or destructive when the two drivers combine. Combined, they create a peak through this range when in phase and a dip if out of phase. The peak is much worse than the dip and steep slopes on both drivers mitigate the problems.

BTW, you need to be careful what you put back there. When I had a sheet of the adhesive-backed noise mat back there, it created a reflection that made a really nasty dip at ~5KHz in the Heil's response. This is when I realized that changes made behind the driver have a direct impact on what comes out the front.I'm sure your DIY wave guide and back treatments have gone a long way to change the nature of the interaction between the ESS AMT tweeters and your room and align the imaging with the more traditional type of sound that many of us prefer.


Widget

[toddalin]

Room is 26 feet across and speaker centers are at 7.5 feet so (26 - 7.5)/2 = 9.25 feet. Room is symetrical.

Cabinets are up against the front wall and are 30" deep.

Room is 16 feet deep and speakers are 2.5 feet deep and up to the wall so baffles are at 2.5 feet.

Couch cushion (sweet spot) is 10.5 feet out from speakers so 16 - 2.5 - 10.5 = seating is 3 feet from back wall. When I lean forward, away from the cushions, things get better. The speakers are toed in to the sweet spot using a laser pointer.

Front wall is 16 feet high and back wall is 7.5 feet.

https://cimg0.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/2000x1333/80-dsc_0007_69409beeed87064ad242cebae7e2a858107c6978. jpg

https://cimg3.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/2000x1333/80-dsc_0035_2e72d8077c0b40613c00ab68b2762c4437e9614e. jpg

https://cimg7.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/2000x1333/80-heil_setup_d2fea17569da70352a141d62c701841cf11fb6a 8.jpg

[Ian Mackenzie]

There is an account of my experiences with sound stage and imaging.

Measurement of enclosure locations
Like many here l found early on that small adjustments to the position of the enclosures. made a clear difference to the sound stage, size and focus of the image. But it was confusing with the number of variables so l started writing down the x z coordinates on a sheet of paper on top of each enclosure. This was with bookshelf loudspeakers on stands including vertically aligned monitors, a pair of 4311’s and a MTM tower monitors. Later on l pursued a more exacting approach with the much larger diy systems.

It’s tricky to make a definitive comparison but a large baffle with a large radiation area delivers a more in your room presentation than a narrow tower system. If it sounds like it’s in your room then that’s a huge advantage if you’re after an immersive presentation.

Effects of Toe in
I then realised that precise measurements required a tape measure to accurately adjust the toe in angle and exact distance from the front wall and side wall. It was at this stage that l reasoned then the side wall reflections and the angle of the reflections were critical to the precision of any imaging. This also had the effect of changing the blend of the direct and the indirect sound at my listening position. With some adjustments l could get an almost seemless soundstage.

Effect of accurate levels
Sometime later l started to investigate the driver levels and l found a switched volume attenuator has a more stable centre image. Originally with a Tandy analogue spl meter l then found calibration of the dreaded L pads produced a more coherent sound stage. I did this empirically to within 1/2 a db with the analogue scale by matching the level right on the zero db marker. Measurements in the 600-2000 hertz range were effected by being anywhere near the front or side of the enclosure.

I subsequently found on jazz genre’s individual instruments were rendered more realistically. It was a more vivid, solid and defined image of a trumpet and saxophone. Not all recordings are created equal however. Kind of Blue does work despite the age of the recording.

Room compromises
Sometime later l changed to a new room that was 4.7 m x 3.8 m. It was heavily furnished and had heavy drapes. I had the enclosures about 2.7 metres apart but l again had to sit further back than was optimal for political correctness.

The rendering of depth was impressive particularly on a well produced recording. The album Toy by Yellow is interesting.

https://en.m.wikipedia.org/wiki/Toy_(Yello_album)

I found opening up the soundstage a compromise between side wall image impact and the centre spacing. If your room isn’t wide enough for large enclosures it’s a bit of a compromise. I’ve experienced this problem with the DD67000.

Summary
What this all this boils down to is getting the absolute best out of what you have in your particular situation. I don’t believe with a sheer diversity of rooms and systems in an online discussion that there are any absolutes as far as loudspeakers are concerned. More importantly it’s your own auditory experience that matters. Your ears are the final arbiter.

Edit. In the case of the legacy systems using the 2308 your ear height (or the loudspeaker height) should be such that the bottom edge of the lens is at ear hight or slightly above. This makes an audibly difference to the sound stage and imaging. Measurements highlight the sensitivity of the crossover region to height at the listening
position.

Accurate driver level matching is very important between channels. Over the 20-20,000 frequency range subtle differences in frequency response level are audible. Just check out phono Riaa stage reviews. A +- 1.00 db is deemed unsatisfactory. You can hear this in comparisons because the ear is sensitive to broad shifts in frequency ranges. Therefore if one loudspeaker does not track in close continuity with the other it will impact on your stereo image in terms of tonal solidity of images and image sharpness.

[Robh3606]

Hello Toddalin

Looking at your photo's you still use your L200/300's?? in your HT? Looking at you side wall and mirror reflection are the side and backwall windows with blinds? Looks like the upper triangle has some kind of material covering and blackout blinds below?

Rob :)

[eso]

... anyone who visits So Cal is welcome to come by and hear/experience a soundstage and image that is totally immersive and unbelievable....

I'd love to take you up on that some time. I'm in Long Beach. Conversely, you could have a listen to my system as well.

Regarding your comments about processing for time aligning horns I'll disagree though. The design I put together for the full Cogent systems I built with Rich and Steve has all of the drivers very close to physical alignment and the hardware is such that they are to be fine tuned to their room. Both physical alignment and focus can be adjusted for any listening distance. In my own installation the built-in bass horns are a 5-6 msec behind the midbass, but most people would never notice that in the bottom octave. My system was always designed for full analog so digital correction has never been an option.

When properly adjusted they disappear and create a great image. My own room is small but well treated: not fully dead but enough diffusion and diffraction for really crisp clear sound.

One this I haven't seen mention of as I've scanned this thread is soundstage extending beyond the speakers. If a signal is sent equally to both speakers in phase it will be centered. If phase is reversed in one channel the resulting phase cancellation will shift the image outside on the speaker with the correct phase. If can happen naturally in well engineered live recordings just from the natural room interactions, but it can also be done in the studio.

eso

[Robh3606]

One this I haven't seen mention of as I've scanned this thread is soundstage extending beyond the speakers. If a signal is sent equally to both speakers in phase it will be centered. If phase is reversed in one channel the resulting phase cancellation will shift the image outside on the speaker with the correct phase. If can happen naturally in well engineered live recordings just from the natural room interactions, but it can also be done in the studio.

eso

Hello eso

Yes Q sound comes to mind for the studio where they use phase to steer images. Roger Waters Amused to Death comes to mind.

Rob :)

[toddalin]

Hello Toddalin

Looking at your photo's you still use your L200/300's?? in your HT? Looking at you side wall and mirror reflection are the side and backwall windows with blinds? Looks like the upper triangle has some kind of material covering and blackout blinds below?

Rob :)

No, I really don't except for the occasional comparison. The imaging on the L200/300s is terrible, but they are definately too far apart to image properly.

One side (behind the Super Reds is mainly covered in windows as is the wall behind the couch. The window blinds have "accordion", black-out material for the projector. The angled window behind the Reds has a sheet of black visqueen to keep out the light.

The side wall opposite the Reds is open to the hallway and dining room for the last ~6 feet as is the back wall behind the couch for ~6 feet.

https://cimg3.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/1320x2000/80-dsc_0005_2__75ddd75070b9a86904e6b6d6d49b5a48198719 4d.jpg
https://cimg2.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/1320x2000/80-dsc_0006_2__4673f6dc25263479f14916c2c4d78773759e29 d5.jpg
https://cimg6.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/2000x1333/80-dsc_0004_b0a990f0bf71768580b2975f81b15a10fe8aa9ef. jpg
https://cimg3.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/2000x1333/80-dsc_0003_dfb678b794c4e394cdd8f9dad44d92e5ed37bb1a. jpg
https://cimg0.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/1320x2000/80-dsc_0002_8d7c9421c00f7d2aefb1cf00daa46169cab3ec11. jpg

[Robh3606]

Hello Toddalin

Nice room! So they are blinds. Do they also work as "acoustic curtains" not knowing how they are made. Are they heavy fabric? That gives you more flexibility to make the room "Live vs Dead" by simply opening closing or adjusting the blinds. Assuming they are adjustable like typical window blinds are.

Do you use them that way at all or are they keep that way all the time to help darken the room?

Rob :)

[Ian Mackenzie]

Room is 26 feet across and speaker centers are at 7.5 feet so (26 - 7.5)/2 = 9.25 feet. Room is symetrical.

Cabinets are up against the front wall and are 30" deep.

Room is 16 feet deep and speakers are 2.5 feet deep and up to the wall so baffles are at 2.5 feet.

Couch cushion (sweet spot) is 10.5 feet out from speakers so 16 - 2.5 - 10.5 = seating is 3 feet from back wall. When I lean forward, away from the cushions, things get better. The speakers are toed in to the sweet spot using a laser pointer.

Front wall is 16 feet high and back wall is 7.5 feet.

https://cimg0.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/2000x1333/80-dsc_0007_69409beeed87064ad242cebae7e2a858107c6978. jpg

https://cimg3.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/2000x1333/80-dsc_0035_2e72d8077c0b40613c00ab68b2762c4437e9614e. jpg

https://cimg7.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/2000x1333/80-heil_setup_d2fea17569da70352a141d62c701841cf11fb6a 8.jpg

Hi Todd,

I think what you have described here and with your pics makes a lot of sense! Your room has the size and virtues like the ceiling to create imaging particularly with a dipole situation.

As l mentioned in my own post and since seeing Eso & your room the diversity of rooms and different systems makes any comparison type discussion about accepting the comments by each user. There really isn’t a qualitative discussion to be had. It’s more about the user describing the imaging in a set format a bit like what l posted earlier.

Edit : l have visited to hear Todd’s system

[toddalin]

Hello Toddalin

Nice room! So they are blinds. Do they also work as "acoustic curtains" not knowing how they are made. Are they heavy fabric? That gives you more flexibility to make the room "Live vs Dead" by simply opening closing or adjusting the blinds. Assuming they are adjustable like typical window blinds are.

Do you use them that way at all or are they keep that way all the time to help darken the room?

Rob :)

They are thick enough and the pleats break thing up such that they do serve as acoustic curtains. But I do leave them down and the room is already more lively than I would like. I've thought about having cork placed on the angled ceiling.

If you listen to one of my videos and you listen to the YouTube direct version, you get a very good sense for what the room is adding and taking away (e.g., floor bounce).

https://youtu.be/krlBTPPehm0

https://youtu.be/GXE_n2q08Yw

[Ian Mackenzie]

Any comments about how you progressed to improve the imaging would be appreciated.

For example l mentioned the level matching and location measurements. My network is more advanced & an acquaplas dusted diaphragm runs full range. This improves the blending of the drivers. Incremental improvements can add up to significant refinement in performance.

[eso]

Some details on the construction of my room... The bass horn mouths include irregular surfaces to break up any mid and high frequency reflections. Also, the while it looks like the equipment racks are connected the the bass horn mouths they are actually suspended on separate frames fully decoupled from the bass horns to avoid as much interaction as possible, and the supports for the equipment include a bunch of upholstered 2" fiberglas absorption to help minimize affecting turntable playback.

Millwork on the rear wall are pieces in several widths, depths and angles. The thinking is that by just breaking up waves and bouncing them against the gabled ceiling the reflection off the ceiling just sends them into the rug and absorbs them. Even the self for CDs on top on the record cases is irregular (I refer the that shelf and the stealth fighter shelf)

Not visible in the build on the record cases. The backs of the cases are only covered with upholstery and the space behind them is stuffed full of R-39 Insulation: They are effectively bass traps.

After setting up the room I also installed some 2" rigid fiberglas panels where the 1st reflections from the mids would hit, and some paper pulp diffuser panels on the ceiling.

And I cannot overstate how effective good room treatment is when it comes to good stereo presentation.

eso

[toddalin]

Any comments about how you progressed to improve the imaging would be appreciated.

For example l mentioned the level matching and location measurements. My network is more advanced & an acquaplas dusted diaphragm runs full range. This improves the blending of the drivers. Incremental improvements can add up to significant refinement in performance.

Getting spacing/toe just so (big time),
Cutting off the rear wave from the Heils,
Adding the rear reflector half round to the Heil (big time)
Time alignment of the drivers
Foams on reflective surfaces (top of speaker, bottom of Heil)
Reduction in crossover/driver "overlap"
Getting the relative driver volumes just right (resistor values). The L-pads are run at max and could be removed.


I had been working on these for years, then after something I did (don't remember) Carlos Santana's guitar was suddenly standing right there "proud" in the room like never before. It only got better after that.

Most current version of crossover (subsequent to any videos).
https://cimg3.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/1586x1079/80-screenhunter_477_feb_05_14_47_e2900d11fa28a12714c8 7c8f0c6c7d84e78f1ce0.jpg

[Ian Mackenzie]

Hi Eso,

Can you advise the angle of your mid -hf corns? Are they conical (straight)?

Also what listening distance works best for you?

[toddalin]

I'd love to take you up on that some time. I'm in Long Beach. Conversely, you could have a listen to my system as well.

Regarding your comments about processing for time aligning horns I'll disagree though. The design I put together for the full Cogent systems I built with Rich and Steve has all of the drivers very close to physical alignment and the hardware is such that they are to be fine tuned to their room. Both physical alignment and focus can be adjusted for any listening distance. In my own installation the built-in bass horns are a 5-6 msec behind the midbass, but most people would never notice that in the bottom octave. My system was always designed for full analog so digital correction has never been an option.

When properly adjusted they disappear and create a great image. My own room is small but well treated: not fully dead but enough diffusion and diffraction for really crisp clear sound.

One this I haven't seen mention of as I've scanned this thread is soundstage extending beyond the speakers. If a signal is sent equally to both speakers in phase it will be centered. If phase is reversed in one channel the resulting phase cancellation will shift the image outside on the speaker with the correct phase. If can happen naturally in well engineered live recordings just from the natural room interactions, but it can also be done in the studio.

eso

Nice set-up. I'll have to try to get over there sometime. If the drivers are close to physical alignment, that is time alignment. As Stereophile notes, it is better to be close than far. BTW, one gent on the other forum noted that he had tri-amped Klipsch and when he used a processor to time align the signals, the imaging dramatically improved.

As far as extension of soundstage, yes, mine goes out well past the speakers, and sometimes, past the room. The other day I was listening to the Dave Mathews Band and the flute was behind me over my right shoulder.

[eso]

Hi Eso,

Can you advise the angle of your mid -hf corns? Are they conical (straight)?

Also what listening distance works best for you?

The horns are conical and are based on a design from Bill Woods. Both the mid and midrange horn original designs are the same as used by ΩMA in their system with a Cogent mid range.

However Rich and I modified the mid horn. We shortened it a little while maintaining the mouth diameter. This opened the angle of the horn to match part of the most extreme internal geometry of the Cogent phase plug. The result was improved clarity. The drivers are so powerful we weren't looking for compression to increase sensitivity. The resulting horn is a 52˚ 12-sided conic.

My own room is small and I'm ~12' from the voice coils in the main arrays. It's a giant pair of headphones, but it works great for my listening. Further in a bigger room could be better.

eso

[Mr. Widget]

Nice set-up. I'll have to try to get over there sometime. If the drivers are close to physical alignment, that is time alignment. As Stereophile notes, it is better to be close than far. BTW, one gent on the other forum noted that he had tri-amped Klipsch and when he used a processor to time align the signals, the imaging dramatically improved.Hmmm....


Nice set-up.Yes!


I'll have to try to get over there sometime.A bit of a road trip for me, but I'd love to.


If the drivers are close to physical alignment, that is time alignment.But with a vertically staggered array unlike a concentric speaker it can only be time aligned for one listening position. Meaning a lower or higher seat or standing will no longer be time aligned... also the drivers need to have their acoustic centers aligned, not necessarily the voice coils.


As Stereophile notes, it is better to be close than far.They say a lot of things that are absolutely false. Stereo is designed to be an equilateral triangle, plain and simple... though I agree that sometimes a system sounds better if we deviate from that sightly. I wouldn't generalize though.


BTW, one gent on the other forum noted that he had tri-amped Klipsch and when he used a processor to time align the signals, the imaging dramatically improved.I'm sure he believes that. I would be shocked if it was confirmed in a blind test.


Widget

[toddalin]

But with a vertically staggered array unlike a concentric speaker it can only be time aligned for one listening position. Meaning a lower or higher seat or standing will no longer be time aligned... also the drivers need to have their acoustic centers aligned, not necessarily the voice coils.

Widget

Right. Only one person listens at my house. Note how the Heils are aimed down to my ears.

Right. And this is why I use an RTA at the sweet spot to determine the smoothest response regardless of how they actually stack forward/rearward.

[Ian Mackenzie]

Hmmm indeed.

Excuse me gentlemen while l interject.

If we going to challenge or question each others views being expressed please include your reasoning or evidence with your view or your challenge. See below an example:

In theory there can only ever be one spot don you think?

Dave Wilson was a pioneer in adjusting time aligned systems.

My understanding is that timing can influence localisation. See the quote from research below. If the harmonic structure of an instrument isn’t time aligned with the fundamental or the harmonics and overtones then there is a problem with some staggering of the arrival timing and the phase shifting during the time domain.

For example listening to a crash cymbal after its struck till when it ultimately fades.

This is about precision and as noted by Andrew Jone it’s where the cost goes up in more elaborate loudspeaker systems.

[Quote]

https://www.sciencedirect.com/topics/medicine-and-dentistry/sound-localization#:~:text=Sound%20localization%20refers %20to%20the,Musiek%20and%20Chermak%2C%202015).

“ Sound Localization and Binaural Sound Lateralization Tests.
Sound localization is based on binaural cues (interaural differences), or differences in the sounds that arrive at the two ears (i.e., differences in either the time of arrival or the intensity of the sounds at the right and left ears), or on monaural spectral cues (e.g., the frequency-dependent pattern of sound filtering caused by the angle of incidence of the sound with the external ear). Interaural differences are used mainly for left-right localization, whereas spectral cues are used for vertical and back-front localization.”

[Ian Mackenzie]

Right. Only one person listens at my house. Note how the Heils are aimed down to my ears.

Right. And this is why I use an RTA at the sweet spot to determine the smoothest response regardless of how they actually stack forward/rearward.


Todd,

I have visited your home and l admire your ingenuity & persistence.

If only we had more like you.

[Robh3606]

But with a vertically staggered array unlike a concentric speaker it can only be time aligned for one listening position. Meaning a lower or higher seat or standing will no longer be time aligned... also the drivers need to have their acoustic centers aligned, not necessarily the voice coils.


Widget

Yes one point only within some tolerance hopefully not in inches. If you move outside the window it degrades so with changes to distance and height the driver arc would change. The real question is just how audible this really is. There are very few true Time aligned systems and as long as you stay within the B+L curve for group delay you should be OK.

I played with that once in one of my older systems and depending at what height I measured the speakers at I could get very close to the single spike triangle step response.

The Arrays are not time aligned and yet they manage to image well as an example.

See figure 19 in attached page from Improvement in Monitors

Rob :)

[toddalin]

More on imaging.

Listen to this track (I'm sure that many have it). You have shrunk yourself down and are standing on the piano just behind the keyboard with the strings laid out infront of you. As each note is played you can hear the sound move to the left/right such that each string is clearly defined in space. This is not something you would hear in the real world standing next to a piano. I'm sure many classical pieces are recorded like this too.

https://www.youtube.com/watch?v=JBchE1PMkg8

[toddalin]

Todd,

I have visited your home and l admire your ingenuity & persistence.

If only we had more like you.

Thanks. You know that you always have a place to stay if you get up to this area.

[Ian Mackenzie]

Hi Rob,

Here attached is far more insightful and relevant information from the Project Array Designer himself.

See the attached documentation

https://support.jbl.com/on/demandware.static/-/Sites-masterCatalog_Harman/default/dw5afac441/pdfs/JBL%20800%20Array_Project%20Array%20Brochure.pdf


[Quote]
“The final major feature is the capability of the horn to be moved forward or back without creating baffle discontinuities. This allows the horn HF and LF drivers to be lined up in the depth direction to achieve the best time behavior over a large frequency range. This also allows the drivers to be "in polarity" in addition to "in phase" at the crossover point.
The sum total of these main features is a loudspeaker system with the speed and dynamics of a compression-driver system, but with the smoothness and imaging of the best direct-radiator and panel systems.”

So obviously the time behave matters or he wouldn’t have gone to all that trouble with the industrial design.

If you unbolt your Array horn and move it you may not hear the difference but other people might. You might be as deaf as a post or the next person might be. Your own biases may also influence what you hear. All that matters is what you hear on your own system and no one gets hurt.

[Robh3606]

Hi Rob

So obviously the time behave matters or he wouldn’t have gone to all that trouble with the industrial design.

If you unbolt your Array horn and move it you may not hear the difference but other people might. You might be as deaf as a post or the next person might be. Your own biases may also influence what you hear. All that matters is what you hear on your own system and no one gets hurt.


Hello Ian

I think you are missing the point I was trying to make. He made sure that group delay met the B+L curve in the figure I posted. That is the threshold for audibility,

I didn't say it wasn't addressed or not important in the design as obviously it was and is going forward.

Take a look at the impulse response. It's obvious he put summing through the crossover and the polar response before time alignment. He knows what counts and what to emphasize.

You don't need textbook time alignment to make a well engineered speaker that images well.

Also moving the horn front to back only works for the woofer and mid 435Al driver. It does not in any way change the physical offset between the 435Al and the 045Ti tweeter that clearly leads the other 2 drivers.

Here is the step response. First one posted 1400 Array

The step response in a time aligned system on the designed axis is a single triangle with no differentiation visible between drivers.

Also attached is the step response on the Wilson system that takes a rather extreme and brute force approach to time align their speakers by making the baffle adjustable to distance and ear height.

They get much closer to ideal where their emphasis is time alignment. Wilson Speaker post 126

Rob :)

[eso]

Hi Rob,

Here attached is far more insightful and relevant information from the Project Array Designer himself.

See the attached documentation

https://support.jbl.com/on/demandware.static/-/Sites-masterCatalog_Harman/default/dw5afac441/pdfs/JBL%20800%20Array_Project%20Array%20Brochure.pdf


[Quote]
“The final major feature is the capability of the horn to be moved forward or back without creating baffle discontinuities....

Being fully adjustable was a primary requirement for the Cogent main arrays.

Early on Rich and I worked on locating the balance points of each horn/driver assembly and mounting those assemblies around their balance points while having the drivers physically aligned became the basic layout for the racks.

Zero position was suspending the mid horn and driver at it's balance point with a pivot and struts that allowed a good +/- range on the vertical axis. The midbass assembly is able to move forward or backward to maintain physical alignment with the mid while moving up or down as needed to focus with the mid and the desired distance.

Finally the tweeter needed to be able to move in yet another axis to align with both of the other drivers. Sourcing all of the various hardware took a while, and once we had it Rich's machining know how was needed to adapt everything.

And then other features just help to make a cohesive system. One side of the racks distributed the signal wiring and the other side fed the field supplies. Crossover network mounted in the base of the rack.

I made a variation on these racks for my system here. I needed something shorter

eso

[Robh3606]

Hello eso

Hey they look just like stainless steel turnbuckles used on a sailboat to tension the rigging! Cleaver idea infinitely adjuatable.

Rob :)

[Ian Mackenzie]

Edit : For those involved or just lurking my endeavour in this thread has been to engage members to express in their own words what they done themselves in so far as the imaging of their system is concerned. There have been some great posts to date.

Keep it coming.

[Robh3606]

Hi Rob,

You posted the Array was not time aligned when in fact JBL literature says it was.

[Quote]

“ The Arrays are not time aligned and yet they manage to image well as an example.


It was misinformation while casting your own interpretations. That just confused everyone reading your post. That is why l posted the attachments.

The only facts relevant are about original design as outlined in the attachments.
I unfortunately don’t have time to go through the rest of your post right now.

The same thing applies to anyone attempting to opinion their bias on a particular design as to whether they believe it or not? What that does it pollutes the whole thread with half arsed polarising opinions which then makes others very reluctant to post about their experiences with that system or something else. Why would you bother?

This isn’t your bottom of river US political campaign.


By definition they are not time aligned.

It is not misinformation.

The step response cannot be denied.

As far as half arsed polarizing opinions

Just read one.

Rob :)

[Ian Mackenzie]

[QUOTE=Ian Mackenzie;446889]Hi Rob,

Here attached is far more insightful and relevant information from the Project Array Designer himself.

See the attached documentation

https://support.jbl.com/on/demandware.static/-/Sites-masterCatalog_Harman/default/dw5afac441/pdfs/JBL%20800%20Array_Project%20Array%20Brochure.pdf




Being fully adjustable was a primary requirement for the Cogent main arrays.

Early on Rich and I worked on locating the balance points of each horn/driver assembly and mounting those assemblies around their balance points while having the drivers physically aligned became the basic layout for the racks.

Zero position was suspending the mid horn and driver at it's balance point with a pivot and struts that allowed a good +/- range on the vertical axis. The midbass assembly is able to move forward or backward to maintain physical alignment with the mid while moving up or down as needed to focus with the mid and the desired distance.

Finally the tweeter needed to be able to move in yet another axis to align with both of the other drivers. Sourcing all of the various hardware took a while, and once we had it Rich's machining know how was needed to adapt everything.

And then other features just help to make a cohesive system. One side of the racks distributed the signal wiring and the other side fed the field supplies. Crossover network mounted in the base of the rack.

I made a variation on these racks for my system here. I needed something shorter

eso

Hi eso,

Beautiful work.

I wish l could organise this.. really clever. I found the Tad 4003 really too heavy to balance on the Bill Woods A700. I’ve since moved the Tad’s on and plan to use a lighter Neo 1.5 inch driver. They are amazing horns. It’s all about the way the wave front travels through them. They are the last ones Bill made apparently. Steve Schell put me onto Bill. I have negativity engineered the OMA Monarch as a diy project in Hornresp. It has a throat with an acoustic high pass filter on the bottom woofer to avoid comb filtering. It’s about 105 db from 35-700 hertz with dual AE 15M woofers. I must revisit this project.

[Ian Mackenzie]

Hi Rob,

I have attempted to interpret what your technical explanation about.

I honestly don’t understand that your trying to get across?

Your coming at this from a very specific point of view. But where’s the relevance and all the supporting data. There’s no documentation so l don’t understand. There’s no labelling so l don’t see how you can expect me to comprehend this?

The best thing to do is post this another thread and provide a comprehensive coverage of the whole thing.

Btw the commentary from Greg only refers to the horn and the woofer.

This thread is not deep dive into a particular loudspeaker. But you seem to think you have a point to make. Do it in another thread.

[BMWCCA]

:lurk:

[Robh3606]

Hi Rob,

I have attempted to interpret what your technical explanation about.

I honestly don’t understand that your trying to get across?

Your coming at this from a very specific point of view. But where’s the relevance and all the supporting data. There’s no documentation so l don’t understand. There’s no labelling so l don’t see how you can expect me to comprehend this?

The best thing to do is post this another thread and provide a comprehensive coverage of the whole thing.

Btw the commentary from Greg only refers to the horn and the woofer.

This thread is not deep dive into a particular loudspeaker. But you seem to think you have a point to make. Do it in another thread.



Well lets keep this simple.

The 2 systems you referenced are time aligned the Dunlavy SC-IV and the Wilson Alexx V

Since this is a thread about imaging and most speakers are not time aligned it seemed prudent to point this out. Time alignment means all drivers arriving at the same time to the listening position.

I am not making this about a specific speaker. It's really about two different design philosophies.

You don't need to have time alignment to image well. It may help but it's not an absolute.

The Array is not and you can see this in the step response. All 3 drivers have very clearly separate arrival times. Tweeter, Mid and Woofer in that order.

The Wilson is better but has a driver out of phase so the negative spike

Finally the Dunlavy which gives you a perfect step response where all drivers are in phase, shown as a single triangular spike, where you cannot see the drivers individually.

The figures are Array Wilson and Dunlavy in that order.

Rob

[Ian Mackenzie]

I don’t see any labels or the source of your data?? No proof or evidence. Fail.

Were your school assignments this vague? I hope this is a joke.

I have attached the essentials of the Array 1000 so anyone looking can make sense your quandary. In my earlier posts l referred to the designer’s comments. They stand.

The matter of the tweeter isn’t relevant because it wasn’t mentioned by the designer or by me. I will go over that latter ….yawn. It’s 1.36 am.

The primary crossover point is the woofer and the horn. Technically and in practice to enable a smooth crossover transition in the horizontal axis and through the vertical axis (over a defined angle) this is best done by alignment of the woofer and the horn acoustic centres. That way the Linkwitz 24 db acoustic crossover transformation (per JBL document) can be achieved with both drivers in acoustic and electrical phase (per the designer).

The main mission is to keep any nasty nasty dips in the vertical polar pattern outside the defined vertical listening window at the crossover point.

So the designer tweaks this with the horn by testing various positions until a satisfactory compromise is met. Now the location of the horn acoustic centre may NOT be exactly in alignment of the woofer. The (business ) impact on the smoothness of the crossover region takes precedence over minor ( and l mean minor) time alignment discrepancies.

To explain the 750 hertz crossover point as a wavelength of 458 mm. A half wavelength is 229 mm which is the point of a 180 degree phase shift. Now if the horn acoustic centre was 15 mm behind the woofer to obtain the best vertical polar response this would equate to an 11.7 degree phase shift. Relating this 15 mm the actual time delay looks like this. A 1 ms delay is 0.344 of a metre. Therefore a 15 mm is 0.04 ms. This is an example of what this is all about. If it was 150 mm that is a 111 degree phase shift. Referring to the previous example that is about 0.33 of a ms. Well below the BL group delay threshold at 750 hertz of 2.5 ms.

According to your ancient BL Threshold for group delay it’s 2.5 ms at 750 hertz. Therefore l suggest your technical measurement is irrelevant.

Now the tweeter horn. I don’t have the drawings of the tweeter placement but let’s say it 150mm forward of the compression driver. Referring back to your BL group delay threshold curve at the 8000 hertz tweeter crossover point the threshold is about 1.8 ms. That expressed as a distance is 0.6192 of metre. Is the tweeter time alignment therefore important? No it isn’t.

A pertinent point is that the tweeter is there to improve the subjective performance of the stand alone horn above 8000 hertz. In JBL language everything is done for a good reason. It has a relatively narrow vertical polar pattern. This means it unlikely to be heard when the listener is standing up. To an extent the horn vertical polar pattern will fall off when the listener stands up. This is of course dependent on the listener distance.

For all intents and purposes this is a time aligned system in so far as the BL group delay threshold is concerned. If this system was very precisely time aligned then it would seriously impact on other audibly performance criteria.

If the horn crossover point was much higher like 2 or 3 khertz then everything would need to be re evaluated.

It’s important to point at that a high frequency resonance or diaphragm break up an occur in a 0.1 ms to 6 ms range. Are these things audible ? Yes they can be and that’s why little horn tweeters are sometimes used.

[Robh3606]

I don’t see any labels or the source of your data?? No proof or evidence. Fail.

Were your school assignments this vague? I hope this is a joke.

I have attached the essentials of the Array 1000 so anyone looking can make sense your quandary. In my earlier posts l referred to the designer’s comments. They stand.

The matter of the tweeter isn’t relevant because it wasn’t mentioned by the designer or by me. I will go over that latter ….yawn. It’s 1.36 am.

The primary crossover point is the woofer and the horn. Technically and in practice to enable a smooth crossover transition in the horizontal axis and through the vertical axis (over a defined angle) this is best done by alignment of the woofer and the horn acoustic centres. That way the Linkwitz 24 db acoustic crossover transformation (per JBL document) can be achieved with both drivers in acoustic and electrical phase (per the designer).

The main mission is to keep any nasty nasty dips in the vertical polar pattern outside the defined vertical listening window at the crossover point.

So the designer tweaks this with the horn by testing various positions until a satisfactory compromise is met. Now the location of the horn acoustic centre may NOT be exactly in alignment of the woofer. The (business ) impact on the smoothness of the crossover region takes precedence over minor ( and l mean minor) time alignment discrepancies.

To explain the 750 hertz crossover point as a wavelength of 458 mm. A half wavelength is 229 mm which is the point of a 180 degree phase shift. Now if the horn acoustic centre was 15 mm behind the woofer to obtain the best vertical polar response this would equate to an 11.7 degree phase shift. Relating this 15 mm the actual time delay looks like this. A 1 ms delay is 0.344 of a metre. Therefore a 15 mm is 0.04 ms. This is an example of what this is all about. If it was 150 mm that is a 111 degree phase shift. Referring to the previous example that is about 0.33 of a ms. Well below the BL group delay threshold at 750 hertz of 2.5 ms.

According to your ancient BL Threshold for group delay it’s 2.5 ms at 750 hertz. Therefore l suggest your technical measurement is irrelevant.

Now the tweeter horn. I don’t have the drawings of the tweeter placement but let’s say it 150mm forward of the compression driver. Referring back to your BL group delay threshold curve at the 8000 hertz tweeter crossover point the threshold is about 1.8 ms. That expressed as a distance is 0.6192 of metre. Is the tweeter time alignment therefore important? No it isn’t.

A pertinent point is that the tweeter is there to improve the subjective performance of the stand alone horn above 8000 hertz. In JBL language everything is done for a good reason. It has a relatively narrow vertical polar pattern. This means it unlikely to be heard when the listener is standing up. To an extent the horn vertical polar pattern will fall off when the listener stands up. This is of course dependent on the listener distance.

For all intents and purposes this is a time aligned system in so far as the BL group delay threshold is concerned. If this system was very precisely time aligned then it would seriously impact on other audibly performance criteria.

If the horn crossover point was much higher like 2 or 3 khertz then everything would need to be re evaluated.

It’s important to point at that a high frequency resonance or diaphragm break up an occur in a 0.1 ms to 6 ms range. Are these things audible ? Yes they can be and that’s why little horn tweeters are sometimes used.

OK so basically JBL is not in the time alignment camp like most other manufacturers. You just admitted it in your explanation.

Like I said in my original post. As long as the design meets the B+L graph I originally posted. That means below the curve not at 2.5 Msec at 750Hz where it becomes audible.

Like the 3 systems graphed that are below the threshold.

Those are Stereophile step response graphs buy the way.

Why don't you just admit the 1400 is not time aligned/coincident as in the review? What's the big deal?

Text from the Array Review

"In the time domain, the 1400 Array's step response on the tweeter axis (fig.8) indicates that all three drive-units are connected with positive acoustic polarity, and that the tweeter output arrives at the microphone half a millisecond before that of the midrange, which in turn arrives half a millisecond before that of the woofer.

This is definitely not a time-coincident design, though the fact that the ear/brain does integrate arrivals over a longer period than 1ms should mean that this won't matter much.

LG was impressed by the stability and accuracy of the JBLs' imaging, which you'd think might be adversely affected by the lack of time coincidence.

But as far as the lower-frequency units are concerned, the 1400 Array's step response is at least time-coherent, in that the overshoot of the midrange unit's step smoothly leads into the woofer's step.

This suggests an optimal crossover implementation."


The Key is optimal crossover implementation which again I said in my post. Smooth driver integration and good polar response being the main focus.

Essentially all well designed systems are time-coherent. There is a difference they are not the same.

Rob :)

[Mr. Widget]

Well lets keep this simple.

The 2 systems you referenced are time aligned the Dunlavy SC-IV and the Wilson Alexx V

Since this is a thread about imaging and most speakers are not time aligned it seemed prudent to point this out. Time alignment means all drivers arriving at the same time to the listening position.

I am not making this about a specific speaker. It's really about two different design philosophies.

You don't need to have time alignment to image well. It may help but it's not an absolute.

The Array is not and you can see this in the step response. All 3 drivers have very clearly separate arrival times. Tweeter, Mid and Woofer in that order.

The Wilson is better but has a driver out of phase so the negative spike

Finally the Dunlavy which gives you a perfect step response where all drivers are in phase, shown as a single triangular spike, where you cannot see the drivers individually.

The figures are Array Wilson and Dunlavy in that order.

RobThanks Rob!

While it is true JBL did some time alignment work on the 1400 Array... physically pushing the mid/tweeter array forward, it is obvious from the impulse response that they needed to move it further. That said, for practical reasons it is also obvious why they wouldn't want to do that.

That Dunlavy impulse response is VERY impressive... but I bet it is only achieved when measuring on tweeter axis vertically and horizontally.


I don’t see any labels or the source of your data?? No proof or evidence. Fail.

Were your school assignments this vague? I hope this is a joke.Dude... what is your problem? Geez!


Widget

[eso]

[QUOTE=eso;446891]

I found the Tad 4003 really too heavy to balance on the Bill Woods A700. I’ve since moved the Tad’s on and plan to use a lighter Neo 1.5 inch driver. They are amazing horns. It’s all about the way the wave front travels through them. They are the last ones Bill made apparently. Steve Schell put me onto Bill. I have negativity engineered the OMA Monarch as a diy project in Hornresp. It has a throat with an acoustic high pass filter on the bottom woofer to avoid comb filtering. It’s about 105 db from 35-700 hertz with dual AE 15M woofers. I must revisit this project.

Bill is a brilliant man.

When we first started experimenting with the conical horns Bill had cast some of his throats for the Cogent drivers (their throat is a unique size, ~2.7"). But using Bill's throat design limits the petal thickness to 3/4". For purely aesthetic reasons I thought the petals should be thicker to visually balance with the mass of the drivers. So I asked rich to machine an adapter that bolts to the drivers with a ring with set screws mounted in the horn. I think it's a much cleaner attachment and the horn mass is a nicer balance.

And also this allowed the previously mentioned tweak Rich and I implemented on the mid horns. I know there's a thread here about horn/driver interactions at the throats and volumes elsewhere as well. We were seeking to make a perfect match for our efforts.

ΩMA still uses the 3/4" petals with Bill Woods' throats now badged ΩMA.

eso

[rusty jefferson]

Thanks Rob!

While it is true JBL did some time alignment work on the 1400 Array... physically pushing the mid/tweeter array forward, it is obvious from the impulse response that they needed to move it further. That said, for practical reasons it is also obvious why they wouldn't want to do that.

That Dunlavy impulse response is VERY impressive... but I bet it is only achieved when measuring on tweeter axis vertically and horizontally.....


Widget
Excellent example of everything in speaker design being a compromise. 1400 are really good sounding speakers. Appreciate the knowledge Rob.

I've never seen a speaker with passive networks have an step response like that, only active. I'll have to read that article.

[toddalin]

I've never seen a speaker with passive networks have an step response like that, only active. I'll have to read that article.

https://i.ebayimg.com/images/g/-SMAAOSw71JkEhJa/s-l1600.webp

[jmpsmash]

Very interesting discussion!

I am on the time alignment camp. Hard to achieve given all drivers are of different shape and depth. One would have to do what Dunlavy did, or have to resort to waveguide, or DSP.

When I was playing around with the 2397/2441/2216ND1 (still remember that thread?), I was just a beginner and couldn't figure out why I was never able to get clean FR like I see on many speakers. Then over the years I spent a lot time learning about crossover design and then I realized the depth of the horn caused the acoustic center to be way far behind the woofer. And with computer tools, this can be easily simulated. The following are 2 theoretically ideal driver, originally perfectly aligned but was pushed so that they are one crossover wavelength (2000Hz/17.1cm) apart. Still phase aligned but not time aligned. The excess phase causes big ripples in the FR.

For anyone who has DSP active filters, it is very quick to do a similar experiment. change the delay to keep the drivers phase aligned but not time align, listen to it, and then change it again to be time aligned, the image will suddenly become much more defined.

[Robh3606]

https://i.ebayimg.com/images/g/-SMAAOSw71JkEhJa/s-l1600.webp

Have you seen any step response measurements on them? I had an 811C as a center for years and it was a great vocal speaker.

Rob :)

[toddalin]

Have you seen any step response measurements on them? I had an 811C as a center for years and it was a great vocal speaker.

Rob :)

No, but I remember seeing one opened up on C/L and it was packed with caps and chokes.

Also, there are these for sale in Long Beach.

https://images.craigslist.org/00l0l_gaGbUjyJNsG_0CI0t2_1200x900.jpg

https://images.craigslist.org/00P0P_gC6jnEEv2nh_0x20oM_1200x900.jpg

There is also a very good chance that my Super Big Reds are time aligned through the dedicated electronic crossover. But they still don't image like the Mermans. Maybe they would if located in the same places.

[1audiohack]

....The Array is not and you can see this in the step response. All 3 drivers have very clearly separate arrival times. Tweeter, Mid and Woofer in that order.

The Wilson is better but has a driver out of phase so the negative spike

Finally the Dunlavy which gives you a perfect step response where all drivers are in phase, shown as a single triangular spike, where you cannot see the drivers individually.

The figures are Array Wilson and Dunlavy in that order.

Rob

Hello Rob;

The Dunlav response is an ETC measurement, unlike the two above that are impulse responses. There is no return through zero in an Energy Time Curve display. Dominated by the HF energy it looks great but it is not at all a fair visual comparison.

Barry.

[toddalin]

To which:

The responses on the Wilsons have always "baffled" me. They go to extensive steps to line up the acoustic centers and aim them all at the receptor location. But the the step responses still show three distinct driver signals arriving at the mic. If things are time aligned, shouldn't the signal from three drivers hit the mic simultaneously??? What am I missing here?

[Robh3606]

Hello Rob;

The Dunlav response is an ETC measurement, unlike the two above that are impulse responses. There is no return through zero in an Energy Time Curve display. Dominated by the HF energy it looks great but it is not at all a fair visual comparison.

Barry.

Hello Barry

Let me go back and check the other 2 certainly could have made a mistake.

Here is the Dunlavy review and they have both Impulse and Step Take look what do you think?

Rob :)

https://www.stereophile.com/content/dunlavy-audio-laboratories-sc-iv-loudspeaker-measurements

[Robh3606]

Ok here is the Array 1400 review it's a step response have a look. No impulse shown???

Rob :)

https://www.stereophile.com/content/jbl-synthesis-1400-array-bg-loudspeaker-measurements

[1audiohack]

Hi Rob;

Thank you for the link. #3 is the impulse response of the Dunlav. It is very good indeed.

Barry.

[Robh3606]

To which:

The responses on the Wilsons have always "baffled" me. They go to extensive steps to line up the acoustic centers and aim them all at the receptor location. But the the step responses still show three distinct driver signals arriving at the mic. If things are time aligned, shouldn't the signal from three drivers hit the mic simultaneously??? What am I missing here?


Just went back to look at the review and I made a mistake they are calling in Coherent and not Aligned. He had an issue with the measuring distance and he goes through it in the review. He didn't measure at a point that the speakers were adjusted for. Kind of clouds the measurement. Also look at Foot Note 2 That is again labeled as a step response.

Check out the review here:

https://www.stereophile.com/content/wilson-audio-specialties-alexx-v-loudspeaker-measurements

[Robh3606]

Here is another time aligned Vandersteen so you can compare the step to the Dunlavy

https://www.stereophile.com/content/vandersteen-model-seven-mkii-loudspeaker-m7-hpa-monoblock-power-amplifier-vandersteen-seven

Rob :)

[1audiohack]

You are right Rob, no ETC measurement on the 1400 ARRAY article.

Barry.

[rusty jefferson]

https://i.ebayimg.com/images/g/-SMAAOSw71JkEhJa/s-l1600.webp

Todd, I'm not sure if you've also been following the UREI Discussion thread and the Differences Between Compression Drivers thread but there's overlap in both of those that brought us back to this thread. The parameters needed for good imaging and soundstaging, which are not necessarily the same thing. The UREIs image well but can't create a soundstage. Recently, Mr. Widget asked...

I would love to see the impulse response of a UREI coax... I'll bet it is not truly time aligned. I would expect that it is improved over the original Altec/JBL, but I doubt they were able to nail the impulse response with simple passive components.
Widget
...to which there has been discussion about whether the UREIs are actually time aligned since none of us has seen an impulse response of a UREI monitor, and now discussion of the Dunlevy impulse response (passive components) that is likely much better than the 40 year old UREI design.

[toddalin]

I'm of the opinion that proper/good imaging goes hand-in-hand with a proper/good soundstaging.

Imaging is the ability to precisely place an object/instrument/voice in space and soundstage provides that space for this to occur. If there is no real soundstage (i.e., clearly defined space), how can you locate anything in it?

[Mr. Widget]

I'm of the opinion that proper/good imaging goes hand-in-hand with a proper/good soundstaging.

Imaging is the ability to precisely place an object/instrument/voice in space and soundstage provides that space for this to occur. If there is no real soundstage (i.e., clearly defined space), how can you locate anything in it?By the nature of the topic you are absolutely right, and if Rusty or anyone else disagrees 100% he is also right.

To my knowledge there has not been a thorough and definitive definition put forth by someone of the standing of Floyd Toole, so I think we will have to assume that imaging, soundstage, and their interaction or overlap are almost uniquely defined by each of us.

I am sure there is plenty of overlap in our definitions as well in what we deem good or important, but short of gathering a group of us in one place, with each of us experiencing the sound from the sweet spot and then comparing notes... this becomes tricky to define at best.

I would submit the soundstage is the entirety of the sound being played back in a stereo or multi-channel audio system and the image is the illusion of what is happening within that soundstage.


Widget

[Mr. Widget]

Hi Rob;

Thank you for the link. #3 is the impulse response of the Dunlav. It is very good indeed.

Barry.Can you say textbook? ;)


Widget

[Robh3606]

I would submit the soundstage is the entirety of the sound being played back in a stereo or multi-channel audio system and the image is the illusion of what is happening within that soundstage.


Widget

Hello Widget

I agree with your definition

Rob :)

[toddalin]

Just a broader way of saying the same thing. So then, what determines what is a good soundstage/image?

Would you want to listen to some "nebulous" bubble of sound floating infront of you, or a clearly defined space with width, depth, and height?

[Robh3606]

Just a broader way of saying the same thing. So then, what determines what is a good soundstage/image?

Would you want to listen to some "nebulous" bubble of sound floating infront of you, or a clearly defined space with width, depth, and height?


Simply put you do. You seem to be very happy with your speakers and you worked hard to get there.

Many others would and could be happy with less as far as accepting what they hear. Saying "I like that" and just stop there.

I can't hear what you hear unless we are in a shared space. Together we could probably come up with a shared definition after that experience.

I may hear things and point them out and you may as well.

Even a shared experience is personal as we undoubtably have different bias's.

Beyond that I think we are kind of limited to the broad terms used to describe the experience. Especially trying to work this out over the internet.

Rob :)

[Mr. Widget]

Just a broader way of saying the same thing. So then, what determines what is a good soundstage/image?

Would you want to listen to some "nebulous" bubble of sound floating infront of you, or a clearly defined space with width, depth, and height?What determines the image good or bad is one of the topics we have been discussing and speculating on... phase, time alignment, cabinet diffraction, directivity etc.

But I think you meant what do we think is a good image within the soundstage? That is an interesting question and one I have been pondering for a while. A bit over five years ago I started this thread with this quote:

To me a speaker with outstanding imaging will create a holographic soundstage when playing back recordings that are recorded in a manner where there is the appropriate sonic information. If the recording has been recorded in a manner that preserves spatial details, you may hear sounds apparently coming from deep behind the plane of the speakers as well as infront of them. A vocalist may be so locked into the center there appears to be narrow window from which they are singing, and sounds may appear far to the left or right of the speakers and sometimes sounds or instruments even seem to be behind you. I've heard "audiophiles" refer to this as having speakers that "disappear".

Most speakers will throw some form of image and create a soundstage that is likely not that far off from what we are likely to hear at a typical live musical performance. That said, speakers with outstanding imaging create an immersive soundstage that can be quite compelling. This sort of imaging occasionally occurs in live music, but not typically.
And what I was getting at was that while I find holographic imaging wonderfully fun and captivating, real music rarely if ever sounds like that. I listen to a fair amount of live unamplified classical music and the soundstage is huge for a symphony with a large orchestra. The violins are vaguely off to the left, the cellos are slightly to the right, the basses are off to the right, the woodwinds to the center but in the rear etc... but a "well recorded" classical recording can sound anything from a representation of this to a hyper focused audiophile "image"

So which do we prefer? My DIY TADs create a more diffuse image that more closely recreates live music, my point source Meyer speakers create the holographic audiophile type image. I like them both.


Widget

[grumpy]

The way I think about it is this (not intending to be a definition, or even "correct"... much of this has been said already, and I have no horse in this race. Maybe it will resonate... or not):

Imaging can be heard and quantitatively assessed with panned instruments in a stereo recording.

Soundstage includes the realism of the venue (assuming a minimalist mic setup or very well placed mics and effects), sometimes including "depth" or "size" (which can be room/reverb/plates or relative levels) -and- some level of imaging... a coherent preciseness of where a singer or instrument is located adding to the "realism" or "hyper-realism" of the soundstage.

Certainly have been some interesting comments :)

[Robh3606]

So which do we prefer? My DIY TADs create a more diffuse image that more closely recreates live music, my point source Meyer speakers create the holographic audiophile type image. I like them both.


Widget

So the best of both worlds! Always nice to have a second system that's a bit different where you can try things out.

Rob :)

[Mr. Widget]

So the best of both worlds! Always nice to have a second system that's a bit different where you can try things out.

Rob :)Yes, and I appreciate how lucky I am to have two very satisfying systems.

I believe the impetus for my starting this thread was having moved to this new house and giving up my beloved Everests, I was once again using the 1400 Arrays as my primary speakers. The 1400 Arrays while not quite as holographic as the Meyers, were way beyond what the mighty Everests were in the imaging department. Subsequently the 1400 Arrays moved on and the 2007 DIY TADs made their comeback. They image more like the Everests, but on the continuum, they are closer to the 1400 Arrays.

If it was 20 years ago I would play around with them a bit more to learn more about the effects of baffle size, time alignment, etc. but these days, I'd rather just cue up some music and enjoy it. :D


Widget

[1audiohack]

To which:

The responses on the Wilsons have always "baffled" me. They go to extensive steps to line up the acoustic centers and aim them all at the receptor location. But the the step responses still show three distinct driver signals arriving at the mic. If things are time aligned, shouldn't the signal from three drivers hit the mic simultaneously??? What am I missing here?

Hello Todd.

My memory sucks these days, as my days of rigorous studies are far behind me, there may be anything form oversimplifications to outright errors in this. Keeping it simple and short is my goal.

Each speaker device has a delay of its own. They are time invariant devices so different frequencies experience different levels of delay. Every speaker element has an acoustic origin that floats a little or a lot, front to rear over a given frequency range.

There are of course additional and sometimes large delays caused by the dividing network.

Impulse response measurements are dominated by the high frequency in the measurement as there is simply more information there per sample than at low frequencies. Impulse measurements look for peak energy. If the passband of the device under test is band limited, the impulse peak may center on the loudest portion of the received signal and not the highest frequency. Nothing seems certain in audio.

In practice I believe that using the impulse peak response for time alignment is the first rough tool used to get one somewhere in the ballpark. Whether the use of signal delay, physical manipulation or both, of the individual driver units are used to align the impulse peaks, one will undoubtedly end up moving them, in time and or space to get them properly integrated. The HF is going to get moved farther and farther back as compared to the LF.

To my understanding and experience, to achieve anything like the impulse measurement shown on post 154, the drivers must all be operating well within their linear range, the filters gentle, and the mid and low frequency drivers must be critically damped and obviously the drivers are not on the same plane. I am in fact unsure of how you get an impulse response that tight with the LF portion of the speaker in operation. I am not for a minute inferring that the measurement is bogus.

I assume that the Dunlavs are passive? I am going to read up on them a bit.

All the best.
Barry.

[toddalin]

As I noted before, if you listen to Emerson, or lots of piano pieces, you hear the strings laid out infront of you and you hear the notes "bounce" from string to string left to right infront of you. This is never something you would hear in the rear world, but this is what the mics hear, and this is what I want to hear. I don't want to just hear someone playing the piano infront of me as in a piano bar.

[Ian Mackenzie]

OK so basically JBL is not in the time alignment camp like most other manufacturers. You just admitted it in your explanation.

Like I said in my original post. As long as the design meets the B+L graph I originally posted. That means below the curve not at 2.5 Msec at 750Hz where it becomes audible.

Like the 3 systems graphed that are below the threshold.

Those are Stereophile step response graphs buy the way.

Why don't you just admit the 1400 is not time aligned/coincident as in the review? What's the big deal?

Text from the Array Review

"In the time domain, the 1400 Array's step response on the tweeter axis (fig.8) indicates that all three drive-units are connected with positive acoustic polarity, and that the tweeter output arrives at the microphone half a millisecond before that of the midrange, which in turn arrives half a millisecond before that of the woofer.

This is definitely not a time-coincident design, though the fact that the ear/brain does integrate arrivals over a longer period than 1ms should mean that this won't matter much.

LG was impressed by the stability and accuracy of the JBLs' imaging, which you'd think might be adversely affected by the lack of time coincidence.

But as far as the lower-frequency units are concerned, the 1400 Array's step response is at least time-coherent, in that the overshoot of the midrange unit's step smoothly leads into the woofer's step.

This suggests an optimal crossover implementation."


The Key is optimal crossover implementation which again I said in my post. Smooth driver integration and good polar response being the main focus.

Essentially all well designed systems are time-coherent. There is a difference they are not the same.

Rob :)

Hi Rob,

I think don’t appreciate the reasoning behind my previous posts.

Cool your jets, slow down and read my response below:

To explain:

In your earlier post you referred to the BL curve which l think is a good reference for audible thresholds of group delay. What l in fact posted was in the extracts referring to “Time behaviour” if you care to look at that more closely.

So let’s use that BL curve as a baseline for a practical loudspeaker. That is why l did the walk through on the Array 1400.

In my lengthy post l went to some trouble to explain that the acoustic centres of the Array 1400 drivers fall well within the BL threshold.

So what does that mean? It means that a human being won’t detect any group delay errors within the BL curve. Therefore the Array 1400 it’s meets time alignment from an auditory scientific point of view based on my walk through. I’ve actually proved this.

Your line of think seems to be hooked on those step responses tests published in Stereophile.

I quickly read a bunch of the Stereophile reviews. That impulse test is only an indication of what driver arrives first and if the other drivers are in or out of phase. It’s not actually referred to as a time alignment test by John Atkinson. He briefly discussed the impulse tests.

But more importantly there seems to be a consensus that the Project Array systems image very well. No it’s not by the definition of a step response perfectly aligned. I would suggest that as a pointer to imaging isn’t the answer. As far as Stereophile goes they are there to make money and they want to keep you curious so that you continue to subscribe. They know what graphs are attention grabbers. They have got your attention (respectfully). Correct.

So l am not the person getting upset here. It’s about reaching a moment of truth. The Array 1400 is the moment of truth. No it’s not a theoretically time aligned system but it sure a fuck images very well. The proof is in the listening.

There are no absolutes in terms of a right or a wrong. It’s about reaching understanding!
That is where l am coming from.

Where to from here? I think that as far as imaging goes there’s a whole cookbook of things that go towards making it work. It’s about figuring it out.

[1audiohack]

As I noted before, if you listen to Emerson, or lots of piano pieces, you hear the strings laid out infront of you and you hear the notes "bounce" from string to string left to right infront of you. This is never something you would hear in the rear world, but this is what the mics hear, and this is what I want to hear. I don't want to just hear someone playing the piano infront of me as in a piano bar.

Hello Todd;

Don’t you think that depends on where you are listening from? The polar responses of instruments are sometimes predictable but not always.

If you are at the keys, if the lid is open and the music rack is laid down you will certainly hear the piano low left to high right, just as you describe. I quite like that too.

In my youth I (kinda) played trombone, percussion and piano. I would way rather hear a trombone from the mouthpiece than the front. At least up close. (:

Barry.

[1audiohack]

Hi Rob,…So what does that mean? It means that a human being won’t detect any group delay errors within the BL curve. Therefore the Array 1400 it’s meets time alignment from an auditory scientific point of view based on my walk through. I’ve actually proved this….

Hello Ian;

This is where we get into trouble. You contending that the 1400 ARRAY can be scientifically considered to be perceptually time aligned verses the standard measures showing that it obviously is not, is going to be disputed. I understand your point.

Barry.

[Mr. Widget]

Hello Ian;

This is where we get into trouble. You contending that the 1400 ARRAY can be scientifically considered to be perceptually time aligned verses the standard measures showing that it obviously is not, is going to be disputed. I understand your point.

Barry.Yes, once we enter the "perceptual" domain all hell breaks loose. What can the average person perceive, what can a trained listener perceive, what can an individual listener perceive... :blah:
On top of that, there is the whole question of how important time alignment at all. In gross terms, thinking of the original massive Altec theater systems where the HF horns were on sleds to reduce the delay between the woofer/tweeter, there is no question that alignment is important, but when we are discussing "time alignment" in the modern sense, there is a lot of potential debate on the topic.

In my opinion a speaker is either time aligned or it is not... kinda like being partially pregnant, it isn't a thing.


Widget

[Robh3606]

Morning Ian

Just echoing the previous posts once you get into perception it's psychoacoustics and it get's complicated. You have the step responses that are derived from the impulse response and then you have a delay table the B+L laws which are perceptual.

That's Widgets speakers on skids where they are physical moving things around to make sure the physical offset's, which are offsets in time ultimately, are under the line in the B+L table so they are not audible.

Take a look at the 3 systems graphed there. The worst offender is the 4331 and that is because of the long horn used that shifts the acoustic center of the tweeter. After the hump you can see a constant offset where the other two systems have much less delay over the same frequency range.

The kicker is all 3 systems don't have audible group delay even though we can clearly see the delay in the measurements.

What you posted about Greg's efforts I have no doubt definitely contributes to why the 1400's image like they do. That's rooted in his experience and understanding in the balance of measurement and psychoacoustics and what in his experience should be emphasized.

He hit a homerun with that system

Rob :)

[Robh3606]

Hi Rob,

I quickly read a bunch of the Stereophile reviews. That impulse test is only an indication of what driver arrives first and if the other drivers are in or out of phase. It’s not actually referred to as a time alignment test by John Atkinson. He briefly discussed the impulse tests.

Where to from here? I think that as far as imaging goes there’s a whole cookbook of things that go towards making it work. It’s about figuring it out.

Hello Ian

Atkinson is correct you don't use the impulse to determine the offsets you use the Step response. The Step is derived from the Impulse. The Step response shows you the actual alignment offsets in Msec.

You have a measurement system you don't have a Step Response choice in your system??

There is so let's keep the conversation moving forward.

Rob :)

[toddalin]

Hello Todd;

Don’t you think that depends on where you are listening from? The polar responses of instruments are sometimes predictable but not always.

If you are at the keys, if the lid is open and the music rack is laid down you will certainly hear the piano low left to high right, just as you describe. I quite like that too.

In my youth I (kinda) played trombone, percussion and piano. I would way rather hear a trombone from the mouthpiece than the front. At least up close. (:

Barry.

The difference being that close miced, the strings are sonically further apart providing much more separation. Yes, opening the lid and sitting at the keyboard you hear the left/right movement, but you can't "place each string" within that movement.

[toddalin]

Who says that JBL never got into time alignment? Isn't that partially the concept of the 4430? Doesn't the 2425 line up with the 2235?

While my 4430s were not the last word in soundstage and imaging, they were far superior to the L200/300s.

https://www.lansingheritage.org/images/jbl/catalogs/1986_pro/a1.jpg

[Robh3606]

Who says that JBL never got into time alignment? Isn't that partially the concept of the 4430? Doesn't the 2425 line up with the 2235?

While my 4430s were not the last word in soundstage and imaging, they were far superior to the L200/300s.

https://www.lansingheritage.org/images/jbl/catalogs/1986_pro/a1.jpg

I would say no. They are close and you can see that in the B+L curve where the 4430 is graphed. If you go through the Improvements in Monitors paper you will find they have a deliberate offset to tilt the listening axis up when floor mounted. They use a phase delay to tilt so there will be some offset.

I would like to see the step response on that system!

It's a good idea to read it as it addresses the B+L laws directly and as a user of the system it goes through why they image so well in comparison.

Has much more to do with the 2344 horn and directivity than T/A

Remember Time Alignment was Urie's claim to fame. If JBL came out with a T/A system I would think marketing would have been all over that.

There is a lot of information in the B+L table. If you look closely and read the captions the COAX is a UREI system. Look at the group delay through the crossover of the coax and the 4430

Again would like to see a Step on both not sure exactly what's going on.

https://www.audioheritage.org/vbulletin/showthread.php?7852-Improvements-in-Monitor-Loudspeaker-Systems

[Robh3606]

Here is an Impulse response and the derived Step Response on my Array 1400 clone. I also included a flipped version because I screwed up the polarity when I did the measurement.

The Flipped is so the Stereophile and my step can be viewed in the same polarity and not confuse anyone.

Impulse first

Step Response

Flipped polarity Step

As you can see there is a significant difference between the 2 views of the Impulse response,

Rob :)

[eso]

...to which there has been discussion about whether the UREIs are actually time aligned since none of us has seen an impulse response of a UREI monitor, and now discussion of the Dunlevy impulse response (passive components) that is likely much better than the 40 year old UREI design.

Here's a page from a 1977 Urei catalog showing pulse and square wave traces...

I see my super Urei monitors linked again a couple pages back too.

And I also posted a new pair of 615B drivers with time aligned networks using the Don Patten circuit. It's basically the classic Ed Long TA circuit adjusted for the shorter offset of the 605 motor assembly. Whether or not those circuits are truly time aligned, they are a huge improvement over non-aligned notworks.

eso

[Robh3606]

Thanks eso!

Rob :)

[eso]

No, but I remember seeing one opened up on C/L and it was packed with caps and chokes.

Also, there are these for sale in Long Beach.

https://images.craigslist.org/00l0l_gaGbUjyJNsG_0CI0t2_1200x900.jpg

https://images.craigslist.org/00P0P_gC6jnEEv2nh_0x20oM_1200x900.jpg



Those are one of my projects, currently residing in one of my son's rooms...

eso

[eso]

Thanks eso!

Rob :)

I thought I had a DownBeat article with more comprehensive test traces, but I can't find it right now.

In the examples below even though not stated I'd guess the competitors' are a stock 604 and a 604 with a mastering labs network...

eso

[toddalin]

Here's a page from a 1977 Urei catalog showing pulse and square wave traces...

I see my super Urei monitors linked again a couple pages back too.

And I also posted a new pair of 615B drivers with time aligned networks using the Don Patten circuit. It's basically the classic Ed Long TA circuit adjusted for the shorter offset of the 605 motor assembly. Whether or not those circuits are truly time aligned, they are a huge improvement over non-aligned notworks.

eso

These were the time aligned crossovers to which I was previously referring with all the chokes and caps. I see your ads on C/L.

BTW, ever seen the way Hammond delays the signal to create the "chorus" and "vibrato"? It's a bunch of chokes and caps to create a time delay with a scanner.

https://bentonelectronics.com/wp-content/uploads/2011/12/vibrato3.jpg

[eso]

These were the time aligned crossovers to which I was previously referring with all the chokes and caps.

All of the Ed Long TA Networks for Urei used all the chokes and caps...

These are Urei circuits for:
811A (604 8K Ferrite)
original 813 (604 8G + helper Woofer)
811B (PAS 1580CX + JBL 2425)

The Don Patten circuit for the 605 is very similar the the "B" series networks.

eso

[Ian Mackenzie]

A follow up to my previous post.



I went over the a Stereophile Array 1400 review.

Below l have summarised some interesting observations.

1. The specified horn dispersion is 60 horizontal x 30 vertical dispersion pattern. On face value this seems to contradict the M2 140 x 100 dispersion while the DD67000 has a 100 x 60 dispersion.

2. The normalised vertical and horizontal frequency response shows a very smooth very smooth contours with slight fall off in the response above 10khertz.

3. The horn horizontal pattern control appears to be soft beyond the 60 degree specification.

4. The vertical pattern control is tight.

5. See comments by JA in attachment concerning the impulse tests. This confirms my earlier post. Specifically the 1400 Array's step response is at least time- coherent, in that the overshoot of the midrange unit's step smoothly leads into the woofer's step. This suggests an optimal crossover implementation. This validates my earlier post.

Conclusion
The Array horn appears to use the vertical diffraction orientation of the horn to maintain very uniform and extended dispersion. The sound stage created does not rely on a wide horizontal dispersion. Referring to JA’s comment while not time-coincident design (see impulse test) the fact that the ear/brain does integrate arrivals over a longer period than 1ms means this isn’t a problem in this design.

[Robh3606]

'Conclusion
The Array horn appears to use the vertical diffraction orientation of the horn to maintain very uniform and extended dispersion. The sound stage created does not rely on a wide horizontal dispersion. Referring to JA’s comment while not time-coincident design (see impulse test) the fact that the ear/brain does integrate arrivals over a longer period than 1ms means this isn’t a problem in this design."

Hello Ian

FYI not sure where in the review you saw 60x30 but that is not the case. The two horns are not the same pattern. The midrange horn is 80x80 the smaller HF horn is 60x30 look at the JBL Sam1HF tech sheet. The Array 1400 and SamHF1 use identical horns. The pattern on the mid horn is wider than you think based on any info in the review.

Rob :)

[Ian Mackenzie]

Hi Rob,

Thanks for the heads up.

I read it in the Array BG review here on the first page. See attachment and insights from Greg Timbers.

https://www.stereophile.com/floorloudspeakers/jbl_synthesis_1400_array_bg_loudspeaker/index.html

I have attached the SAMHF spec as you referred to.

Interesting.

Between the lines l think the reviewer had a conversation with GT and there is somewhere an mis communication on the actual dispersion. Normally a manufacturer will prepare some technical editorial for a reviewer to publish. I say this because the “Listening Window” is +30 -30 in the horizontal plane according to the SAMHF spec sheet. Sounds like a mix up somewhere…

The measurements are what they are @ 50 “ on axis with the tweeter which is a normal procedure.

At 8 feet and 36 inches (averaged listening height) the measurement of the horn will look more like the curve in the vertical dispersion measurement @ -15 degrees down. It looks fairly smooth. (See attachment)

Therefore the measurements are meaningful. Of course it’s about the listening.

Edit attachment added with marked up horizontal dispersion (40 degrees off axis)
attached the vertical off axis measurement for discussion point in this post.

[Ian Mackenzie]

Just a broader way of saying the same thing. So then, what determines what is a good soundstage/image?

Would you want to listen to some "nebulous" bubble of sound floating infront of you, or a clearly defined space with width, depth, and height?

Good question. At least there’s one scientist in the crowd. (Todd is a scientist)

Looking at the examples posted it’s not about any one design element.

It might look like this

Low diffraction mid and hf baffle
Uniform and extended (HF) CD horn response with soft control angles
Group delay below perceivable levels.
A listening space which complements critical listening

But this is at odds with a conventional box loudspeaker.

It would look like an Ostrich…. The Linkwitz Pluto comes to mind.

That is why the Array as deceptively simple as it is works.

I don’t think working this out is like looking for the Dead Sea Scroll in a really long thread is the answer. People get fixated on catch phrases like Time Alignment and they go down a long endless rabbit hole look for the perfect answer. A time alignment only exists at one XYZ position in front of a loudspeaker. If that was the be all and end all of imaging we’d all have our heads in a vice. Clearly there’s more too it.

IMHO the best way to approach it is simply set your system up on your room as best you can following some credible guidelines and forget about it. Beyond that buy a pair of reputable near field monitors and use them for an imaging fetish. Attempting to buy or build a floor standing loudspeaker box that is the golden egg of imaging is a fantasy.

The best commercial examples look hideous and for that reason have not been a commercial success.

[1audiohack]

….A time alignment only exists at one XYZ position in front of a loudspeaker…

Unless you have something like the Danley SH50 Synergy Horn or another properly executed MEH horn. :)

Barry.

[toddalin]

I was listening to "Clapton Unplugged" on CD this evening. The placement of every instruments' amplifier was clearly defined across the soundstage (well beyond the speakers) and the interplay between the three guitar's strings was clearly audible on a note by note basis. Instruments, such as piano and voice are through the PA and panned into position. The piano is panned between the left speaker and left of center and you can hear the position change with the notes played. The soundstage is better than being there live.

You So Cal guys really need to get over here and hear this!

[Ian Mackenzie]

Unless you have something like the Danley SH50 Synergy Horn or another properly executed MEH horn. :)

Barry.

Hi Barry.

Maybe..🤔 I really admire Danley’s work.

Somewhere Don McRichie summed it up nicely.

The problem is that every time you uncover an unknown the there is another unknown and before long you become obsessed with listening to equipment instead of the music.
For example Dunlavy selected his drivers on the basis of them being close to textbook ideal. However a compression driver loaded by a horn is anything but the ideal. The phase, group delay and amplitude response is all over the place as you know. To correct that requires as you may know FIR dsp capabilities. It’s not without its downside in terms of setting up, complexity and cost. Then you have to say is my system and my situation going to make that sort of precision worthwhile. The only way is to assess it yourself after you’re absolutely certain it’s been implemented correctly. That’s another pain point that not many are prepared to endure. It’s all just too hard…Lol.

Some people might laugh but love playing a bit of Tina Arena in the truck…Lol.

It’s simple and it works.

Enjoy your weekend.

[Ian Mackenzie]

I was listening to "Clapton Unplugged" on CD this evening. The placement of every instruments' amplifier was clearly defined across the soundstage (well beyond the speakers) and the interplay between the three guitar's strings was clearly audible on a note by note basis. Instruments, such as piano and voice are through the PA and panned into position. The piano is panned between the left speaker and left of center and you can hear the position change with the notes played. The soundstage is better than being there live.

You So Cal guys really need to get over here and hear this!

Hi Todd,

I would love to. Next time I’m there. I need to do another tour via my friends in India, Thailand, Croatia, Iceland & Berlin…The last time l started in FS in CA and ended up at Windsor in the UK listening to Merlin’s system. Listening to someone else’s set up is really where it’s at. I think it enriches your appreciation of the hobby. Otherwise it can be a somewhat selfish pursuit. Helping someone by even being a sounding board is so fulfilling.

Can you a post a recording with wave file and stereo mics?

Btw has anyone heard from Clark lately? Clark hasn’t posted for a while. I recall visiting Clark and we did a trip down to catch up with Rick’s …. house of JBL cc 2007. It was a bit overwhelming looking at Rick’s 43XX enclosure production line.

https://www.soundseasy.com.au/products/tascam-dr-07x-handheld-recorder?variant=12895424938083&currency=AUD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&utm_campaign=gs-2018-09-22&utm_source=google&utm_medium=smart_campaign&gad_source=1&gclid=EAIaIQobChMI_oGgk9edhAMVIBatBh3NywuHEAQYASAB EgJPLvD_BwE

[Ian Mackenzie]

Oh on the feasibility of a coaxial or dual concentric driver the time alignment can only ever be set for one angle. This is because the delay required is specific to that angle. 😦 😥

In the overall scheme of things this isn’t the Achilles Heel of a co axial or dual concentric driver. They require acceptance of a number of often critical compromises for that on on axis point sources.

[toddalin]

Hi Todd,

Can you a post a recording with wave file and stereo mics?


I don't have the capability. My recordings are done with a Nikon D750 DSLR taken at the approximate sweet spot. Obviously the stereo mics in the camera don't allow for much separation.

[Ian Mackenzie]

Quote Originally Posted by toddalin View Post
As I noted before, if you listen to Emerson, or lots of piano pieces, you hear the strings laid out infront of you and you hear the notes "bounce" from string to string left to right infront of you. This is never something you would hear in the rear world, but this is what the mics hear, and this is what I want to hear. I don't want to just hear someone playing the piano infront of me as in a piano bar.

[QUOTE=1audiohack;446947]Hello Todd;

Don’t you think that depends on where you are listening from? The polar responses of instruments are sometimes predictable but not always.

If you are at the keys, if the lid is open and the music rack is laid down you will certainly hear the piano low left to high right, just as you describe. I quite like that too.

In my youth I (kinda) played trombone, percussion and piano. I would way rather hear a trombone from the mouthpiece than the front. At least up close. (:

Barry.

Hi Barry,

You make a very good point. Looking at Todd’s post Todd is referring to the mic technique used to record a piano. Presumably two mics. I agree that the production values of a recording can be preferred to hearing a piano live but 25 yards back in the audience.

Being a percussion instrument a piano has a certain dynamic quality where the keys are felt as well as heard. As they say you can pick a live piano in a mall or walking past a house when someone is practicing. You loose that sitting a way back in the audience.

But what l think you’re talking about is the listening location at home relative to the loudspeakers. Are you near, mid or far field? And what is the impact on a piano recorded in this manner? Thats a bit tricky to figure out. But if the recording engineer did it with nearfield monitors and he then checked it with mid field monitors you would have to reason that the listening position would be mid field. I say this because the engineer generally does the mix for the formats being used. The point is who listens near field at home?

I hope that makes some sense.

I totally agree with Todd’s point.

Adding to the mix is that Todd has a dipole loudspeaker depending on how he used the AMT. This may well be the X factor in Todd’s descriptions of his system.

Because no two recordings are alike the recording is the most significant dependency on the production values as far as soundstage and imaging.

The job of monitors and loudspeakers at home is to translate those production values with minimal errors. Of the loudspeakers at home embellish certain traits and it’s to the listeners liking then it’s a success story. If you don’t accept the descriptions as posted that’s your problem.

All this would be much easier to discuss (translate) in a webinar which is something l am looking at on my new audio site.

[Ian Mackenzie]

Hello Ian,

Basically Widget is correct. In the case of the Array 1400, the drivers are aligned in the best way for an in polarity hookup through the crossover topology I chose. To have the drivers completely aligned, the horn would have had to move backwards by one complete wavelength at 800 Hz, making a non practical setup. Of course the UHF is in another time zone.

As for imaging, time alignment has little to do with it. Minimum diffraction enclosures which are extremely vibration free, system matching in terms of response and phase from the left to right channel and super narrow baffles are the most important issues.

The Arrays are easily at the top of their pay grade. They have their set of compromises as do all speakers. There is no perfect loudspeaker, nor will there be in the long term.

Widget is also correct in stating that perfect time alignment can only happen in one spot if the system has multiple drivers. CoAx speakers can sometimes do better in this regard, but are not very capable is most other regards.

Greg

[Robh3606]

Hello Ian

Glad you reached out to Greg. I am going to add this to the System Information on the 1400. It also clearly shows Greg's opinion of the importance of Time Alignment WRT imaging.

Rob :)