Revisiting "Imaging"

[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/...one-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.