4367 Cabinet

[sebackman]

Dear all,

I'm looking for the the cabinet data and port dimensions for the 4367. We have excellent data for the M2 and even CAD files out there, but I have not seen such data for the 4367.

I'm planning to build a pair but flirting a bit with the old L300 design (slanting front and glass top), albeit 2 way.

I will be using either 2430/D2, 2451SL or 2451Be. It will be fun to test them on the 4367 WG as I have not had that before. The M2 WG's I'm reasonable familiar with in different setups and do prefer the 4" driver on them.

-And of course BSS DSP active, but that will be a later story

Any input welcome.

Kind regards
//Rob

[Odd]

88865

88866

[jmpsmash]

My mom has a pair in Hongkong. If no one else has gotten to it, I can ask her to measure the port dimensions. The white paper did say 4" and the drawing and text also shows dual flare. Seems like a regular port tube and not something fancy like the M2.

Which woofer do you plan to use?

[jmpsmash]

My mom has a pair in Hongkong. If no one else has gotten to it, I can ask her to measure the port dimensions. The white paper did say 4" and the drawing and text also shows dual flare. Seems like a regular port tube and not something fancy like the M2.

Which woofer do you plan to use?

Dual port with flares on both ends. The straight middle part of the port is 3". Total length including flare is 5". The outer diameter of the flare is 5"

Parts express supplier uses the straight middle part as the size. The 4367 port would be called as a 3" port instead of 4" port.

[sebackman]

Thank you for the info ODD and jmpsmash

Great info.

Can you please measure how long the non flared piece in the middle is. From the cut away it looks like the ports are made of 3 pieces, two flares and a straight piece in the middle.

Can you also, at your convenience, please make external measurements on the cabinets and port positions so I can put dimensions on Odd's drawing.

I have CAD data on the M2 ports and maybe these are the same (or similar)

Kind regards and thank you
//Rob

[Mr. Widget]

Can you please measure how long the non flared piece in the middle is. From the cut away it looks like the ports are made of 3 pieces, two flares and a straight piece in the middle.

Can you also, at your convenience, please make external measurements on the cabinets and port positions so I can put dimensions on Odd's drawing.

I have CAD data on the M2 ports and maybe these are the same (or similar)
Has anyone heard port chuffing in a classic 43XX or a 44XX or in a DIY system not using undersized ports?

I understand the purpose of flared ports, but other than improving the aesthetics of the port, and giving the manufacturer a clean finished solution that is easier to build in a manufacturing setting than cutting a tube squarely and cleanly finishing it as was required in those vintage systems, I am not convinced that we as DIYers need to follow their lead.

I bring this up because it is difficult to model the port tuning when using flared ports. You can measure, trim, measure, and repeat until you hit the target frequency, but this seems like an unnecessary hassle if performance alone is the goal. On the other hand if the aesthetics of a flared port is appealing to you, then I guess you have your work cut out for you.


Widget

[jmpsmash]

Thank you for the info ODD and jmpsmash

Great info.

Can you please measure how long the non flared piece in the middle is. From the cut away it looks like the ports are made of 3 pieces, two flares and a straight piece in the middle.

Can you also, at your convenience, please make external measurements on the cabinets and port positions so I can put dimensions on Odd's drawing.

I have CAD data on the M2 ports and maybe these are the same (or similar)

Kind regards and thank you
//Rob

Rob, you can find external dimension of the cabinet in the white paper linked to above. The white paper also describe in detail how thick the walls are (1 5/8" for the front baffle, 1" others) so it will be straight forward to deduce the gross volume.

The port has a straight middle section, which is not the same as the M2 which has a concave middle section. I doubt the port will be identical as the box volume and the 15" woofers are different.

The 4367 port seems to be something like this:

https://www.parts-express.com/Precision-Port-3-Flared-Port-Tube-Kit-268-350

The 4367 white paper also has the impedance plot, while in really poor resolution, the port tuning frequency looks to be around 32Hz.

The measurement of the straight port tube I already described in my previous post. I will try to get you the other measurements.

[jmpsmash]

Has anyone heard port chuffing in a classic 43XX or a 44XX or in a DIY system not using undersized ports?

I understand the purpose of flared ports, but other than improving the aesthetics of the port, and giving the manufacturer a clean finished solution that is easier to build in a manufacturing setting than cutting a tube squarely and cleanly finishing it as was required in those vintage systems, I am not convinced that we as DIYers need to follow their lead.

I bring this up because it is difficult to model the port tuning when using flared ports. You can measure trim measure and repeat until you hit the target frequency, but this seems like an unnecessary hassle if performance alone is the goal. On the other hand if the aesthetics of a flared port is appealing to you, then I guess you have your work cut out for you.


Widget

If you get this particular brand, which is the brand sold in parts-express, they included a calculator:

http://www.psp-inc.com/tools2.html

[Anti K]

I understand the purpose of flared ports, but other than improving the aesthetics of the port


Wow, that's new info. If it works.
For me as DIY it's even easyer use straight-edged tube, is even more aesthetic IMHO due to easyer sanding.

And I see I'm not the only fool who wants pair a 4367 WaveGuide with large format CD.

[Odd]

4367 impedance plot

88868

[JeffW]

Wow, that's new info. If it works.
For me as DIY it's even easyer use straight-edged tube, is even more aesthetic IMHO due to easyer sanding.

And I see I'm not the only fool who wants pair a 4367 WaveGuide with large format CD.

Guys run the large format drivers on pretty much any horn they'll fit on. Plenty of guys run them on the M2, I run them on the H4338 that was originally used with a 435AL, Giskard had 476Be on a 1400 Array horn I think at one point.

I think the question I have is why JBL didn't - other than cost, of course. And I imagine they used that dual ring radiator on the 4367 since it's a 2-way, but the 4" stuff ain't bad 2-way with coated Ti phragms, I'm running 2-way during the summer on mine and it sounds fine, better than fine.

[jmpsmash]

Guys run the large format drivers on pretty much any horn they'll fit on. Plenty of guys run them on the M2, I run them on the H4338 that was originally used with a 435AL, Giskard had 476Be on a 1400 Array horn I think at one point.

I think the question I have is why JBL didn't - other than cost, of course. And I imagine they used that dual ring radiator on the 4367 since it's a 2-way, but the 4" stuff ain't bad 2-way with coated Ti phragms, I'm running 2-way during the summer on mine and it sounds fine, better than fine.

looking at the FR from other guys here who tried the various 4" drivers on the M2 horn lens, the D2430K isn't that great compared to them, still have a huge drop going into HF that need to be compensated in crossover design. I went with the D2430K as it is the least hassle/cost to obtain.

[Robh3606]

I bring this up because it is difficult to model the port tuning when using flared ports. You can measure, trim, measure, and repeat until you hit the target frequency, but this seems like an unnecessary hassle if performance alone is the goal. On the other hand if the aesthetics of a flared port is appealing to you, then I guess you have your work cut out for you.


Widget

Hello Widget

What are you using to model?? I use Bass Box Pro, have been for years. I have been using the flared ports for several builds Arrays, B380, LFE subs and my passive monitors. They have all come in within +/-1 Hz of target.

Rob:)

[RMC]

I generally tend to agree with Widget (post # 6) but for different reasons, and it seems to me that sebackman is somewhat condemned to replicate JBL's flared ports in the present case, based on Odd's sketch in post # 2.

I don't use flared ports, not because i don't believe in their benefit when properly designed, but simply because i have doubts about the science, if any, behind most flared tubes sold on the market for cheap. Their specs, other than dimensions, are rarely given, such as the Normalized Flare rate (NFR) value. Then its probably more a trial and error type of thing, or marketing.

That software or calculators are available on the Web for flared vents doesn't change anything in my view. Who wrote these, what are their credentials, what is the science (often obscure at best) supporting this stuff? We simply don't know, it may be good, bad, so so, who knows... Too much is unexplained and unproven about those things.

You think low-cost China, who manufactures most of the ports, flared or not, calculates all that stuff for proper, nevermind optimal, results??

In sebackman's case, replicating the original vents would possibly guarantee properly ENGINEERED flared vents. The use of conventional ports might not be as effective in that context, cab depth could become an issue or the use of an elbow might lead to a space problem.

The most advanced vent study and associated experiments that i know of is still the one from A. Salvatti, D. Button and A. Devantier, Maximizing Performance from Loudspeaker Ports, JAES, Jan/Feb, 2002, P.22. All together 62 pages long! Three seasoned Harman Engineers having quite a go at this, and leaving no stone unturned. I don't have time to retype what's on the pics so consider this as my retyping of that text.

Although, i don't recommend getting the long article from the AES ($) since its pretty heavy material, written by Engineers mostly for Engineers. However the real flared port science is there, no doubt. File size is too large to post, plus the AES holds the copyright on it. Therefore will only post the summary (which is public domain) and limit my quote to two paragraphs. The phrase "The tapered port ..." explains why i think JBL chose this type of vent here. The longer "end correction" being the reason why tapered ports behave as if they were longer.

Richard

8887188872

[Anti K]

In physics it's pretty simple. Differentiating time.

When certain volume of air comes out from tube (at 1/2 sycle talking about speaker), then molecules of THAT amount of air have speed.
We can lower the speed - if amout of air stays same - icreasing diameter of tube.
(and it's quadric equatation!)

near the edges of tube:
- 'Neighrbouhood' molecules, outside of box, 'stand still'.
- Exhausted air molecules have speed and they tear together the standing molecules (at the region of edges of tube). It causes friction. Friction generates sound...

Its all about speed of molecules.

Now, while flared end, the speed of air molecules at the end of tube decreases - while tube diameter increases. And friction should be lower.
Simple as that.

In practice I rebuilt Soviet driver own time as low as 15Hz FS, made them move lower than 20Hz with generator.
(btw causes symhtoms as seasicness)
Only thing I heard was tube turbulence. Flared or no-flared.

What I have read - and it's understandable, there are different frictions between different materials (substances).
And plastiv (PE, PVC etc) are not the best materials for speaker's invewrter tube.
But metal is.
So, going deep it's total madness...


RMC could be right, if take some cheap plastic thing, we can only observe it aesthetically...
Which is basically same MrWidged sayd.

I see what works DIY, is bigger tube (less air speed) ... and bigger diameter makes tube same time longer.
Here was a topic in this forum, person built next to Everests pair of 2x18'' (4 psc total) SUBs, and stated same - did long tubes because *I don't like the hum of short tubes*
Or, take totally original flared parts (and we don't know the resources behind the research of these, M2 special shape for example)

[jmpsmash]

The measurement of the straight port tube I already described in my previous post. I will try to get you the other measurements.

From center of port to side edge of cabinet: 6"
From center of port to bottom edge of cabinet: 5.5"

[sebackman]

Brilliant!

Thank you for all the information. Lots of good data in the White Paper and with additional data from this excellent forum it should not be too difficult build cabinets.

My idea was to make a L300 tribute with slanting flush front and angled edges like the 4333's/4367, using a back firing port. After reading about the 4367 and also other "lower" floor standing speakers it appears that most argue that they sound better with a stand. That kind of defies the L300 low & wide look. Would the slanting front help enough to compensate for the driver being lower that the listening position? Any other drawbacks regarding reflections aso with having a upward tilting baffle?

The K2 S9900 is the same width as the 4367, do you think that would be a better choice to use that as a template? It is 260mm higher. L300 uses slanting baffle to limit standing waves (i guess) and the S9900 use a rounded back. The rounded back is probably very difficult to produce DIY so maybe some angled sides can get me close enough. Input welcome

Maybe there are some left over empty non finished S9900/S9800 DIY cabinets from the the Danish JBL Hornlet factory bankruptcy a few years ago still for sale?? somewhere??

I will probably go for flared port(s) just for aesthetics, looks more modern even if the improvements limited for home use. At lease on the outside. A friend has printed the ports to SUB18 and M2's so that is probably the way I go this time also. We can print in two parts and shorten as needed before assembly.

I usually use DATS3 to set the port length by trial and error. I have used SW programs but I never get it right. Maybe it is use of material or stuffing that is difficult to model. Typically set it a few Hz lower than element rez as I use DSP and can control the curve there.

I have both D2's and several 4" Nd drivers/diaphragms (except Mg) so i just have to try. I use 4" Be's in my other system on M2 WG's but at the cost of needing UHF in the form of 045's. Works fine but these will be 2-ways and hence most likely not Be's.

Kind regards
//Rob

[JeffW]

And it's great that jmpsmash's mom has 4367s! My mom would have come as close to piloting the space shuttle as she would have owning some top tier JBL monitors.

[jmpsmash]

Do you plan to replicate the height of the L300 or 4367?

L300 is 803mm tall, 4367 is 941mm tall.

4367 height is OK to be used without a stand. while the L300 is 6" shorter, and probably why they have a slanted baffle to compensate.

my mom has a stand for the 4367 (~6 inch tall) and she says it sounds better that way. It depends a lot on the listening room and environment. Sitting position will affect the HF height while room modes will affect the LF source location.

Unfortunately due to COVID I have not been able to visit my folks and listen to the 4367.

as for the K2 S9900, personally I love that look. However, back of the envelope calculation shows that with that semi-circular cabinet it barely has 3.5-4 cu ft of gross volume.

I am in the designing stage of building something that has a curve cabinet. but deeper with a cut-off oval shape instead of semi-circle. It will have M2 lens and 2216ND1 woofer. inspired by the design posted in the KM2 thread.

what's the pros and cons of having the port at the back vs front?

[jmpsmash]

And it's great that jmpsmash's mom has 4367s! My mom would have come as close to piloting the space shuttle as she would have owning some top tier JBL monitors.

Oh... Did I mention she is in her 70s? :D

Couple of years ago she came to visit me and we were tweaking my system and she was able to tell differences in the 10kHz+ range (verified with FR measurements)

20 yrs ago she had someone build a pair of custom speakers with a pair of LE15A. She was bummed that some friend was letting go of a pair of 2231A and she didn't take them before another friend snatched it. The LE15A speaker didn't age very well with 20 yrs of high humidity in Hong Kong. Most of the drivers have disintegrated so she got the 4367. I told her to keep the LE15A driver which can still be refoamed but so far no urgency to.

[RMC]

RE "what's the pros and cons of having the port at the back vs front?"

In principle none since VLF radiated is omnidirectional. However, with rear firing vent(s) one must not put the cab's back too close to a rear wall as this will impair vent air flow. So that reduces back wall box placement.

Vent works as well either way as long as you have free air flow. On JBL B460 sub the vents are on a side panel near the back. Then this means cab has to have a distance from side wall.

Box placement flexibility is one reason i always put vent(s) on the front panel. Speaker system placement needs to be experimented with for best sound or most pleasing. When vent is not on the baffle that precludes some box arrangements, such as to back or side walls, which one may regret later. My other reason is psycho i guess (lol), simply prefer front firing vent, i get the impression that output is straight to my ears, like for the drivers.

But i can imagine, justified or not, that rear vent sound may not be exactly in phase with the front sound due to a short delay on the back wave from port having to rebound before reaching the listener maybe? Others may have an opinion on this. Regards,

Richard

P.S. Regarding the last point, i can't recall seeing studio monitors, used in a Prof. studio, having rear firing ports. Could this be an indication?

[Mr. Widget]

P.S. Regarding the last point, i can't recall seeing studio monitors, used in a Prof. studio, having rear firing ports. Could this be an indication?That is simple, pro monitors are often soffit mounted or need to be up against a another surface, so front mounted ports are guaranteed to not be blocked.


Widget

[RMC]

I thought about soffit mount. However, the ones i've seen in recent times were not soffit mounted or up against another surface, but rather "flown" using some ajustable speaker metal support, and angled downwards shooting at the recording engineer's position. In such situation they could have had rear or side firing vents, but they didn't...

[Mr. Widget]

Since the manufacturer can’t control where a monitor will be installed, the safe answer is to place the port(s) on the front.


Widget

[RMC]

Yup, agreed. Plus this way one keeps all box placement options available, i.e. box to back wall, in the corner, etc. Nice to have flexibility.

[sebackman]

I see your point and it is not really important to have the ports in the back, just look less busy. I had two ports in the back on the ”compact monitor” a few years ago and that worked very well. They were LE1400H + 2451/475SL on M2`s. They are now with a friend and still sound among the best I have been able to build. BSS DSP and Crown CTS as always :-)

However, it feel like I`m passing on the 4367 cabinte design and moving towards the higher cabinets like the S9800/S9900 to eliminate the need for stands. The curved rear is too complicated so I will probably make angled sides. Maybe make them romboid... I need to give that some though as there others in our home having views on such matters...

A pair of empty S9800/9900 cabintes from Hornslet bankruptcy would fit the bill perfectly. Must start searching.

Anyway, 4367 WG´s and 2216Nd-1 is in transit as the last set -1 woofers went with my M2´s to a friend. I also have a set of dual 15”s, dual 14” and 18”s if needed...... I`m not planning to use a sub with these, they are only for 2-channel enjoyment.

I`m going to try to make these phase linear. I guess everyone wants that but it is not that simple, not even with a DSP. My reference speakers from Genelec are both frequency and phase linear. They are near/mid field so they cannot replace the JBL`s, but they sound real nice with their digital correction SW. Probably like a 708P or so.

I bought them to keep the DSP fiddeling at sane levels. It is easy o lose the direction when you can change EVERYTHING.

All input much appreciated.

//Rob

[macaroonie]

Hi Rob , in the world of Baltic Birch there are suppliers of pre formed curved sheets.
Think about drum shells but bigger. How you go about cutting etc is a different matter but I have seen various radii on sheets as high as 48" / 1200
You are in the Nordic region so should be able to dig into industrial suppliers.

Here's a linky from the US but the product will not be made there simply because they could not call it 'Baltic'

http://www.aitwood.com/StoreFront.Asp?WoodType=POPLAR&CATID=10&Section=QTRCYL&wDesc=Quarter%20Cylinders%20(90%20degrees)

You will need to dig around in the site to see what exists , I have seen 18mm half round
somewhere on this site. I would be surprised if there was not a Skandi manufacturer out there.

Regards Mac

[pos]

I`m going to try to make these phase linear. I guess everyone wants that but it is not that simple, not even with a DSP. My reference speakers from Genelec are both frequency and phase linear. They are near/mid field so they cannot replace the JBL`s, but they sound real nice with their digital correction SW. Probably like a 708P or so.

The BSS BLU-160 and BLU-80x series do have enough FIR taps for phase linearization, and you could probably build the whole correction in FIR if you settle for a 48kHz sample rate.
I would be happy to provide assistance if you want to use rephase for the task :)

[sebackman]

Hi everyone,

Just wanted to get back on this as I have sold the 4367 Kit to a local JBL enthusiast who will continue the build and most likely this thread. His name is Bjorn.

I got some LSR6332 , but that is for another thread.

Thank you for the support.

//Rob

[sebackman]

Okey, this thread is officially open again. :-)

The first 4367 set was bought by my dear friend Björn but I have a second set inbound that was originally going to a friend that in the end left the table :-( .

So I will build me a set of 4367 clone as originally planned. These will however be faithful to the original design and Björn and his son has put in loads of efforts to re-engineer the design and make the necessary files. Brilliant work form their side. Thank you.

Björn will run original D2 driver and original XO. I will stick to my guns and use my favorite combo 2451 with larger felt back cap and 475Nd diaphragms. I have one new NOS set left.

This means that I will have to move to DSP so any input on curves and filers is much appreciated.

I will keep this thread updated.

Have a nice weekend when it arrives fellow JBL nuts.

//Rob

[jmpsmash]

Rob,

Can you share what Björn have found out about the 4367 construction?

I have the 2216Nd-1, it is in a larger cabinet at the moment. I plan to cut that cabinet down to the same volume as the 4367, and/or build a new cabinet to combine it with M2 horn.

[Jakob]

Do anyone have a parts list for the 4367?

[sebackman]

We are slowly getting there. Parts done awaiting to be put together.

91185
91186
91187
91188

[sebackman]

Starting to look decent.

They will be placed on resessed anti-vibration feet as many of my other builds (40 shore). The stands do have resessed built in wheels in the bottom that are not visible.

One pair will be passive, and I will run my pair active via a BSS DSP. I will also run a large format 4" driver instead for the D2. I have both and will try both but historically I have preferred that 4" river. However, I have no idea how they measure on this wave guide yet.

The stands are made so the amps fit in the bottom of each speaker.

We will try to make alu stickers for the wave guide, without the original adjustment knobs. I will also use an angled metal Speakon 8-pole plug in the rear as opposed to the original plastic terminal.

I have no idea why the pictures wind up on the side as the originals are correct oriented...

91192

91193

[srm51555]

Amazing work as usual.

[Jakob]

Does anyone know what size the threads are in the horn to mount it to the baffle. They seem very close to M5. Could it be UNC 10--24?

[emilime75]

Rob, is there a part number for the 4367 WG? Are they available to the average Joe?

[sebackman]

I can check on the threads in the wave guide over the weekend. Not sure at this point. The "horn neck" is not that sturdy so, as I will run a 4" driver, we will make a small support for the driver in the cabinet. I have D2's also and as they are smaller in diameter such support should not be in the way for a D2 swap if someone would like to do so later.The wave guides are just named "JBL Synthesis 4367 Horn" with an SKU No: 111-0013-001. Please check with "Speaker Exchange" in Florida, they are brilliant to deal with.As from what I hear JBL has limited or closed the access to parts from "Luxury" and many parts from that division is no longer available. PRO is still open as I understand, which would provide for the 2216Nd being available but the 2216Nd-1 not so. This is just what I heard, and maybe someone hear on LH can confirm or falsify.

[sebackman]

Hi again,I believe that the threads in the wave guide are M5's, ie 5mm metric. At least my tap went right in.There are 6pcs M5 inserts on the back side of the wave guide.

[Odd]

Nice work Rob
Looks even better this way.

[Mr. Widget]

Very nice!!!


Widget

[jmpsmash]

Just asked the usual source, 4367 Horn Lens no longer available for purchase.

[emilime75]

Just asked the usual source, 4367 Horn Lens no longer available for purchase.Bummer.

[paulgyro]

I'm seeing some awesome 4367 builds! Does anyone have plans to share?Paul

[sebackman]

As with me, it is always a slow process. -Should have had these done by Christmas, but no cigar.

Ok, some progress.

Stands done with recessed wheels and space for 2HE amps and all cables done. Amps will be located right under each speaker.

It will be Speakon 8p to get the wider contact surface with 2 pairs sin parallell i each plug. The metal Neutrik's are pretty slick. The female's are recessed in the cabinet so I can move closer to the wall, if needed.

I have added some extra bracing in the cabinet splitting all "open surfaces" into triangles as triangles have no natural resonance frequency for standing waves. At least from what I'm told.

In addition the mid section right behind the woofer is lined with Bitumen and wool felt to reduce direct reflections on the rear of the woofer.

The cabinet is then lined with 50mm fiber glass on all walls. Nasty stuff. I use ladies hair spray to keep loose fibers in place... :-)

Ports and port extensions are painted and the next step will be to measure the porting frequency with the drivers in situ and adjust the port length. I'm thinking about 27 Hz or so. I will be running DSP so I can always fix some there.

Adapter plates to large format drivers are done and drivers with my special recipe using D16R475Nd diaphragm in wool felt clad back-cap 2451 cores are done. Look promising. I will not use any protection capacitor with these, but only an -8 db attenuator with 50W alu cooled resistors.

I also built a basic streamer using a Raspberry Pi4, feeding a BSS BLU-USB sound-card and then digitally feeding a BSS BLU-50 4-channel DSP. That will keep the signal in the digital domain most of the way. A volume control is added in the BSS (41 bit floating point) and can be remotely controlled, or by a physical knob at the front of the streamer. I also added a touch screen if the iPad gives up... I added 4 analog inputs just in case... -And a POE Ethernet connection for a BSS wall-controller, if I want to go that direction. ( I have a bunch in a box somewhere...)

I hope they will turn out resonable and potentially an alternative to the M2's, after selling mine. I hope the limited vertical dispersion will be an improvement in my (less that stellar) residential environment. From my measurement the large format drivers seem to really like this wave guide. As mentioned before I did measure 9 different JBL drivers (including D2's) on the VTX, M2 and 4367 wave guides a while back. Data (rather extensive) is available to those who want. Drop me a line and I can give access to a Dropbox.

I know M2 are supposed to be the be best, but in my room they did not perform as good as they can. I have heard them in "studio environment" (side by side with E2) and they are really analytic (as I like it) so I know they can be fantastic. -And I do use the M2 wave guide with my BE drivers in the other system so I hope to be able to compare them later. Albeit they are 3-way due to BE limited bandwidth above 14-15k on the M2 wave guide.

Below some pictures. I will add some measurements when I get there.

[sebackman]

More pictures

[sebackman]

Even more...

[sebackman]

A few more...

[sebackman]

Getting there. The last picture is the bracing and driver support that has been mounted. Quite time consuming. But now the cabinets are quit silent when I do the traditional "finger-nock exercise". :-)

[Wardsweb]

Love the level of this build. Kudos to you sir. Well played.

[srm51555]

Stellar work as usual Rob. Nice touch on the focals

[sebackman]

Ok time for some updates on my 4367M clones.

Drivers sorted and IMHO well matched (see separate thread) and cabinets done since a few months.

All open surfaces inside reinforced with diagonal braces forming triangles that do not have natural resonances. Walls lined with bitumen plates, wool felt and fiberglass. I use ladies hairspray on the fiberglass to avoid lost fibers exiting the the bass ports. Ports are deeper to get to an f0 around 26-27Hz.

They did get heavy... :-( but rather "dead" when doing the old finger-knock on the walls

Drivers mounted on the horns with the adapter plate and stickers in place. Looks decent.

I will mount the horns next week. Then the fun stuff begins in designing the DSP filters . I will start with IRR filters as I feel comfortable with that process. Later I will kindly ask the FIR giants like POS to help me to turn them into phase linear FIR filters. Exciting.

Have a nice weekend

[maxwedge]

Those loooook awesome! Very impressed with your work! :applaud:

[Odd]

Very nice work and finish.

[Mr. Widget]

Those loooook awesome! Very impressed with your work! :applaud:

Very nice work and finish.

What they said!

Widget

[Jakob]

Vackert!Thank you for sharing your work!Im really looking forward to see how your dsp filters turn out. With your informative posts I bet I will learn quite a lot!

[sebackman]

First one done after a good year. Mounting those wave guides is not fun. Not much room to bolt from the rear with all the bracing. My own fault of course.

Will do the second tomorrow, I hope. Then the DSP fun begins.

Drivers are matched NOS 2451SL cores with NOS 475Nd diaphragms. My favorite combo. Woofers are of course 2216Nd-1 as they should.

F0 is about 26-27 Hz, right where I wanted it. Sheer luck I guess. Ports are prolonged about 3". You never know until its all in the cabinet.

To make parody on the old Carlsberg beer add; Probably The Best 4367M In The World...

Have good weekend

//Rob

[sebackman]

First impression with a cheap-and-dirty DSP curve is very promising.

I think one of the main advantages of the large format driver and the 4367 wave guide is that horn load extends down to the 500Hz region. The drivers has rising impedance from about 650Hz and XO at 700Hz is probably about right.

I dialed in some LR24 with a few EQ points, guesstimate delays and adjusted phase and that was not half-bad. I run mono in the workshop for initial tests.

Beyond that I really like the matched 2451 cores with the 475Nd diaphragms. That combo seem to love the newer JBL wave guides.

The 2216 just loves power and my smaller shop amps is no match for my down-ported 2216Nd-1's. The current it can provide is just not enough. I had the same experience with the woofer in the LSR 6332 (252G 4 ohms), they just needed a big amp to come to life even on low volumes.

Will bring down my normal ref Genelecs and LSR6332's tomorrow just to get a better feel for potential differences. The next few weeks will be getting a good DSP file in order. Exciting times.

Have nice weekend
//Rob

[Mr. Widget]

Exciting times.
//RobIndeed!


Widget

[Earl K]

Lovely Work!

:)

[emilime75]

First impression with a cheap-and-dirty DSP curve is very promising. I think one of the main advantages of the large format driver and the 4367 wave guide is that horn load extends down to the 500Hz region. The drivers has rising impedance from about 650Hz and XO at 700Hz is probably about right. I dialed in some LR24 with a few EQ points, guesstimate delays and adjusted phase and that was not half-bad. I run mono in the workshop for initial tests. Beyond that I really like the matched 2451 cores with the 475Nd diaphragms. That combo seem to love the newer JBL wave guides.The 2216 just loves power and my smaller shop amps is no match for my down-ported 2216Nd-1's. The current it can provide is just not enough. I had the same experience with the woofer in the LSR 6332 (252G 4 ohms), they just needed a big amp to come to life even on low volumes.Will bring down my normal ref Genelecs and LSR6332's tomorrow just to get a better feel for potential differences. The next few weeks will be getting a good DSP file in order. Exciting times.Have nice weekend//RobRob, excellent work, as usual. What is the net volume of the enclosure? What amp/s have you been testing with that you don't feel have enough power? Do you think the 2216ND would work as well as the -1 in the same enclosure?

[sebackman]

Thank you for all the encouraging comments. This project has consumed a few hours so far. :-)

Emilime, I don't know what the net volume is. Mine are probably a few liters smaller due to additional bracing, bigger driver, longer ports and additional damping. The latter would acoustically probably enlarge the cabinet but the rest would not.

I have no passive XO's in the cabinets so maybe they are where they should be.

The shop amps are dual Alesis RA300's (2x90W RMS) connected to my shop BSS DSP XO. I use two amps to be able to run 3-way, if needed, and use the last channel as direct reference to tara out the electronics when using dual channel measuring. That way I don't really have to calibrate the electronics as I only measure the difference between a "clean" signal after the power amp and the microphone signal.

As far as I understand the difference between 2216Nd and -1 is a thin ribbon of Aquaplas on the rear side of the cone to increase the Q and potentially a stronger magnet to compensate. I have not seen a spec on the -1 but the 2216Nd is in the driver info section here, courtesy by Giskard. However, someone from JBL once told med (right or wrong) that the -1 has a stronger magnet to achieve the lower end in combination with the heavier cone in a passive structure.

This should theoretically give some more deep bass without active filters/DSP. If you run with the original filters you may have to measure the low end and maybe compensate with tone controls/EQ/DSP. That is what the M2 people do anyway :-) . If you go active you are good to goo. Just adjust in the filter/DSP +3-6db @ 30-ish Hz.

I have had both and cannot identify any sonic difference in the all so important midrange.

Happy Friday

//Rob

[Robh3606]

Has anyone heard port chuffing in a classic 43XX or a 44XX or in a DIY system not using undersized ports?


I bring this up because it is difficult to model the port tuning when using flared ports. You can measure, trim, measure, and repeat until you hit the target frequency, but this seems like an unnecessary hassle if performance alone is the goal. On the other hand if the aesthetics of a flared port is appealing to you, then I guess you have your work cut out for you.


Widget

Hello Widget

Depends on the software. With mine I can model double flared, single flared and just about any other configuration. Also the instructions that come with them are quite good you end up calculating the length of straight section that joins the flares. Too answer your question I have had issues with port noise on a couple of JBL's but the smaller systems.

Rob :)

[sebackman]

Finally after many years the 4367M's are finally live. Still quite a lot of work on curves but promising.

Today is the first day I play music on both of them. I did build a basic streamer with a RPi 4 feeding a BLU-USB digitally (via USB) and then digitally to the BSS DSP, and hence nothing analogue in the chain. The BLU DSP feeds two CTS600 under each 4367. Volume is done in the digital domain in the BSS.

I will move to a different BSS within a few weeks that has digital out card and use SOTA external DAC's. Don't really know it it makes any difference but just because I can and have most of the stuff :-) .

But for now it is pretty enjoyable. I can share the curves later when I'm done.

As of now I will tweak them a little and then compare with my M2/476Be/045 as can be seen in the picture. I will probable also add my LSR6332/LSR6312 and my small Genelec references to compare.

Let the feast begin.

[Earl K]

Nice!!!

:)

[Robh3606]

Yes Very Nice!!!

Rob :)

[Mr. Widget]

Finally after many years the 4367M's are finally live. Still quite a lot of work on curves but promising.

Today is the first day I play music on both of them...Congratulations!

That's a lot of speakers. I can hear your neighbors complaining from my house!


Widget

[srm51555]

Yes, very nice work as usual!

[Jakob]

Splendid, they really turned out great! I bet it's quite rewarding to be able to finally listen to them after all the time and effort you've put in.

It seems the 2216's knocked out the bear though :) !


Would be very helpful if you could share the dsp-setup; filters, eq etc when ready.

Just out of curiosity, how do your FR usually end up? Do you go for a Harman-like curve, a flat line or perhaps concave?

[macaroonie]

Damned good work there Rob

[sebackman]

Thank you for all the kind words. Now the difficult part starts.

The DSP streamer V2.0 is now operative. I finally settled for a BSS BLU-160 with both digital and analog inputs & output cards. It is configured as a preamp with analog input by RCA, XLR and digital by SPDIF/AES and BLU-Link.

I wanted to take the DAC output a step further so I got two stand-alone E50 stereo DAC’s which are fed digital SPDIF out from the BSS.

There is also a streamer in the box. It is based upon a RPi4 running Volumio OS and feeding the BSS via Blue-Link thought a BLU-USB soundcard. Pretty neat when running TIDAL.

All up to DAC’s kept in the digital domain. I even included a RIAA DSP settings on the analog input, if there should be a temporary urge for vinyl.

There is a remote controlled DSP volume control incoporated in the BSS and the DAC’s also has a remote controlled HW volume control.

The next step will be to set some base DSP curves. So far all I can say is that it is very clean. The 476Be om M2 + 045 on K2S9900 still sounds better, but give me a few weeks. :-).

[sebackman]

Ok, so the 4367M is finished and they turned out quite good.

As mentioned above the streamer is done and in the end I dropped the BSS BLU-USB unit and went for a Toping D10B (USB to SPDIF). The original setup was a BSS BLU-50 DSP with no digital in and hence the incorporation of the BLU-USB to feed digital input (via BLU-Link). After some fiddling I went with a full BLU160 DSP that I equipped with both analog and digital in and out cards and hence I could use the Topping D10B to feed SPDIF in, to keep everything in the digital domain.

I have now spend more hours thank I like to admit to find a good base line for the drivers and some good XO points.

I think we are close but they are so sensitive so any small change changes the outcome very audible. They are very transparent and revealing to the material chosen.

Kind regards
//Rob

[Mr. Widget]

Very clean and gorgeous design… it is a shame we can’t share the actual audio experience as easily as we can share photos. (apologies to those who think watching a video of a hifi suffices)


Widget

[sebackman]

Here are some curves for those so inclined

1. JBL curve for 2216Nd-1


2. My curve is similar but a small difference due to cabinet. OBS, composite quasi anechoic curve from several measurements (FF + NF)


3. After countless iterations this is the curve I came up with for the woofer. It is a composite quasi anechoic curve with near field measurements for ports and cone (170ms raw data) and far field with different windowing. Far field is used above 300Hz with a 210Hz baffle step correction applied. 10ms time window is used from 300Hz to 600Hz, 6ms windows from 600-1200ms and 3ms window above 1200Hz.

5. Below is the driver measurement which is also a 9ms window at 60cm. Not bad. XO LR24 @150Hz


4. XO tuned out to be time consuming. In the end I ended with 12db Butter for the driver at 700Hz and a LR24 at 730Hz for the woofer. Not to shabby.


Now its time to give it a few weeks to listen and compare to other systems. All of the ones I have have a feed from a RPI4 so I can switch in real time to compare.

I will return in a few weeks with some findings. For now it has similar sound pattern as my PRO1400/476BE/045 wall mounted 5.2 system and similar to the mid-field reference Genelec system, but time will tell.

I will also move the LSR6332/LSR6312's into the room later to compare.

4 decent systems to compare in real time in the same room with the flip of a switch, that will be fun.

Pretty happy with this outcome, without having an original pair of D2 based 4367 I would argue that my 4357M does hold their ground compared to my memory of he originals. I do have some D2's in the shop but they will go for sale now.

Kind regards
//Rob

[Ian Mackenzie]

Hi Rob,

How did you approach the EQ of the 4367 WG?

I take it the acquisition of the 4367 WG was luck.
It’s unfortunate that this particular project cannot be experienced by others as its form fact fits more into the sensibilities of residential home decor.

[jmpsmash]

How did you managed to get measurements so clean in the sub-150Hz region?

[sebackman]

Ian, the large format drivers on the 4367 is really very nice behaved. There is a humb around 1,5kHz and the normal CD fall off from about 4-5kHz. I put a wide "minus" Bell to lower the hump and a normal boost High Shelving to compensate for the fall off. That cleared most of it. On top of that I took the liberty to correct some minor peaks & troughs. I also gave some boost under 1kHz to get a decent curve to at least 600Hz (drops from 550Hz) to be able to XO at 700Hz.

Rather basic EQ points in the end, but it takes a long time to find a combo that achieves your goal with minimal intervention. I can post the EQ settings later today, if of interest.

jmpsmash, the last two graphs does not contain info below 300Hz and may look like "nice curves" but it is really a too short measuring window to display any data there. The first two graphs are composite graphs that use data from both near field (<0,5cm from cone and in port, @85dbA, 170ms window.) measurements, that are reasonable free from room reflections, and gated far field measures (at least 1m out for a 15" DUT).

After measuring the cone and the ports near field I then add all 3 of them into a combined "near field curve" with little to no room reflections visible. Ports will play "louder" due to smaller radiating area compared to the woofer so that need to be compensated for when adding them.

With a 15" woofer near field data can be used to about 350Hz from where it is less accurate. Above 300Hz I merge far field measures. To get reasonable resolution I use 3 separate measures for each composite curve, 9ms 300-600Hz, 6ms 600-1200Hz and 3ms above. So the second of "my" curves is really a combination of 6 measures (2x ports, 1x near field cone and 3x far field)

Its a bit time consuming to do the process for each EQ correction but I don't know how to get clean data in the lower frequency area in any other way. You can measure outdoors but to elevate the 4367 high enough to remove floor/ground bounce would be a challenge due to size and weight. There are some doing ground plane measurements and that may be a good alternative. I did play around with that earlier but did not find that it gave any major improvement compared to the above described method.

Kind regards
//Rob

[sebackman]

Ian, please see attached the measurement of the 2450SL/475ND driver on the 4367 wave guide without any EQ applied. Not too shabby :-) .

The large format 1,5" driver cores really loves the newer JBL wave guides (VTX, M2 & 4367) .

Measurement is done 90 degrees straight in front and 67cm out. The time window is 9ms so the ripple is mostly room reflections and are much less pronounced with a 3ms window. Especially above 5kHz. Please note that there is no smoothing applied. Mic is corrected Earthworks M50.

Kind regards
//Rob

[Mr. Widget]

Ian, please see attached the measurement of the 2450SL/475ND driver on the 4367 wave guide without any EQ applied. Not too shabby :-) .

The large format 1,5" driver cores really loves the newer JBL wave guides (VTX, M2 & 4367) .
Any ideas what is causing the ripples above ~10kHz? It looks like comb filtering from a tweeter, but since there is no tweeter, perhaps diffraction within the horn throat?

Mostly just a curiosity as I doubt we can perceive it.


Widget

[Robh3606]

Any ideas what is causing the ripples above ~10kHz? It looks like comb filtering from a tweeter, but since there is no tweeter, perhaps diffraction within the horn throat?

Mostly just a curiosity as I doubt we can perceive it.


Widget

You see that in all of the 4 " coated/uncoated Ti s. It's secondary resonances in the diamond surround.

It's essentially controlled break up modes in the surround in the last octave. Page 3 attached Technote

Rob :)

https://www.audioheritage.org/vbulletin/showthread.php?4410-JBL-Technical-Notes-Volume-1-Number-8

[Mr. Widget]

You see that in all of the 4 " coated/uncoated Ti s. It's secondary resonances in the diamond surround.

It's essentially controlled break up modes in the surround in the last octave. Page 3 attached Technote

Rob :)

https://www.audioheritage.org/vbulletin/showthread.php?4410-JBL-Technical-Notes-Volume-1-Number-8Of course... I haven't played with diamond surrounded diaphragms in years (decades).


Widget

[sebackman]

Hi,

Its not there in a 3ms window so it is room or cabinet.

Btw the 475nd dia has a coated diamond pattern.

Will post 3ms measure tonight.

Rob

[Ian Mackenzie]

Good Job,

That non normalised horn curve is almost a linear (straight) mass roll off. Shouldn’t be to difficult to EQ .

By the way are you subjectively preferring the conventional drivers over the D2 annular motor? I was looking at some updates on the JBL Luxury Group page and it looks like the V shaped single annular polyester diaphragms are creeping into the product ranges. The phase plug is shaped like a cone. They are reasonably cheap at The Loudspeaker Exchange. On a small wave guide they would make a nice diy super tweeter….!

“At the core of the 2410H-2 device is a lightweight, polymer, annular diaphragm that improves high-frequency extension by reducing diaphragm mass”. BMS have gone the same direction with their hi end compression drivers. There are noises in the Voice Coil Loudspeaker Industry Journal that beryllium diaphragms could on the way out as new man made materials emerge.

A material called Textreme has evolved with a new level of stiffness. See attached.

[sebackman]

Rob, I think you are right but it is probably more or less neglectable today. I recently did a shoot-out with 9 JBL 1,5" drivers on VTX, M2 and 4367 wave guides with many different measures on each (+400 all-in-all) and they all show similar ripple of about +/- 1-2db above 10khz.

I do think the technical manual linked was from the time before the coherent phasing plug (from 2446) and modern day wave guides. You still see some of that but but I argue that it is now reduced. Some ripple is no doubt present but it does not, in my opinion, pose any audible issues.

Below is a driver graph with shorter time window, 3ms @67cm distance. Note that there is NO smoothing.

It is probably better than many other mid/tweeter systems on the planet, especially taking phase and distortion into account.

As we are seldom provided "raw data" from "High Street" speakers, we don't really know how they measure. There are some measurements on the ASR forum and but Erin but they are Klippel "system data", albeit as good as it gets. It would be really interesting to see anechoic data for each element in cabinet for a bunch of High End speaker to compare. I think our JBL's would come out with flying flags.

Most drivers JBL look the same regardless of diaphragm but the 475Nd dia seems to be slightly "calmer" as is has a coated suspension. I would argue that none of the +8kHz ripple is audible with coated or Mg/Be dias. The Ti ones tend to sound a bit harsh when EQ'd, IMHO.

Ian, yes they are easy to EQ but it takes time to reduce the number of EQ points and still get the desired result. Rather time consuming, but fun. DSP is a fantastic tool that lets you do all the measures and corrections in real time. Pandoras Box for us speaker builders.

I have not had a chance to try the new "super-drivers".

I personally prefer the 4" drivers to the D2's on most wave guides. The 4" has more power deeper, which in my experience is audible especially on piano and deep female voices. I did try the D2's on the 4367M's but prefer the 2451/475Nd combo.

Given a choice, I think a really good matched pair of SL's are preferable to the Be's as the Be's will need UHF support and the improvement compared to the technical complication and high price makes it less a compelling combo to me (I have both). I have not had any MG's and maybe they are the Holy Grail. If they were available and had no problem with corrosion.

Compromises, compromises. :-)

Kind regards
//Rob

[Robh3606]

Rob, I think you are right but it is probably more or less neglectable today. I recently did a shoot-out with 9 JBL 1,5" drivers on VTX, M2 and 4367 wave guides with many different measures on each (+400 all-in-all) and they all show similar ripple of about +/- 1-2db above 10khz.

I do think the technical manual linked was from the time before the coherent phasing plug (from 2446) and modern day wave guides. You still see some of that but but I argue that it is now reduced. Some ripple is no doubt present but it does not, in my opinion, pose any audible issues.

Most drivers JBL look the same regardless of diaphragm but the 475Nd dia seems to be slightly "calmer" as is has a coated suspension. I would argue that none of the +8kHz ripple is audible with coated or Mg/Be dias. The Ti ones tend to sound a bit harsh when EQ'd, IMHO.

Compromises, compromises. :-)

Kind regards
//Rob


Hello Rob

I never said they were audible??? Just referenced the tech sheet as a reference and probable cause.

I took a look at the 2450 non SL data on the site. You can see impendence ripple and a decided rougher output from 9K and up.

I agree the techsheet is dated but the basic surround concept is still the same and mode of operation is still in use. And who knows what if any changes JBL has made to the surround's.

I have never seen an SL diaphragm with a coated surround?? That certainly makes the 475's a stand out. I also attached a some 2453SL data to review. Shows ripple and slower decay last octave in the waterfall.

Rob :)

[sebackman]

Hi,

Rob, sorry did not mean to imply that you did say that the resonances are audible. Just wanted to make a point in that we, at least I do, sometimes chase to resurrect issues that are not there. I have spent ours chasing the "final" point and lost the "whole" on the way there. For me comparing to a reference is the salvation to keep me sane. :-)

Attached are the DATS3 impedance curve for the 2451/475Nd driver on the 4367 horn in my actual 4367M cabinet. The resolution is not fantastic but the resonances are limited from what I can see.

The 4" diaphragms come with coating on the dome only, coating on half the surround and coating on the entire surround. I have no idea why. The newer ones seem to only cover the dome. There are other subtle differences on diaphragms supplied in boxes with the same markings. JBL may be better on speakers that QC.

Best regards
//Rob

[Robh3606]

Hello Rob

No harm no foul and frankly who hasn't been down the "rabbit hole" at one point or another.

Thanks for the coating info learn something everyday didn't know there were variations on the theme with the 4" diaphragm's.

Just for info the 476Mg has a smooth Imp curve as well as a clean CSD compared to the 2453 10K and up so go figure????

I started a new thread addressing the secondary resonance WRT materials and surround geometry in General to keep this on topic.

https://www.audioheritage.org/vbulletin/showthread.php?43762-Differences-between-compresion-drivers


Hello Ian

I only have the above mentioned 4" drivers. As far Oswald's Mill no interest. Even if I could swing the prices I don't like the looks. It is also appointment only so why waste someone's time??

Rob :)

[Ian Mackenzie]

Okay,

I will edit / delete my above posts.

[Mr. Widget]

As far Oswald's Mill no interest. Even if I could swing the prices I don't like the looks. It is also appointment only so why waste someone's time??
I would change that statement to "Even if they were the best measuring and sounding speakers extant, I have no interest due to their high school woodshop aesthetic."

Thanks Rob for starting those other threads. I think we should explore those topics more thoroughly and not hijack this wonderful project thread.

Ian, you have posted some interesting and useful posts above. I think it would be great if you would repost them on Rob's new thread(s).


Widget

[sebackman]

Hi all,

I have now had the 4367M (M for Modified 😊) operational for some time and had the chance to develop some quasi anechoic and in the room DSP curves. The room is pretty ok except for a nasty modal at about 30Hz. The curves are nice and smooth from about 30hz to 20k. Even phase looks decent.

The first observation is that they are very neutral and revealing. Not very sensitive to placement compared to my former M2’s, but do benefit from some toe-in. IMHO they work better on some stands to get the driver exit in listening height.

I did extend the ports which demanded some DSP support, but I think it works just fine and does provide that low end quite effortless. F0 is 27Hz.

I was happy.

Now that is of course not enough so a few days ago I invited some seasoned JBL friends for a shoot-out. They all have trained ears and excellent systems at home. At least 2 are in their prime so their ears are still intact. For the older crowd time is probably taking its toll, albeit I can still hear 15k on a good day 😊.

We added a pair of LSR6332 monitors with LSR6212 subs, a pair of LSR708i and my active standard system with SUB1500/1400PRO/476Be/M2/045. Very different systems but to some extent related to one and other. 708i’s are well known to be excellent. The 6332 were the monitor reference of its time and still no slouch. The go-to system that I normally use is very neutral I have spent a ridiculous amount of time on the active DSP setup. They sound and measure very behaved.

Would the fully active, 2451/475 DSP enhanced 4367M clones measure up? Scary.

To add to the competition there was a high end HiFi trade show in town the same weekend and that we visited. They had speakers there priced over $100k.

It was by no means a blind test and does not aspire to be scientific in any shape or form.

We did assemble some decent electronics and I would even go so far to suggest that most was SOTA parts. My friend “Beatelund” managed to get us a brand spanking new $10k Lyngdorf MXA8200 8-channel amplifier, right from the HiFi show in Barcelona where it was shown for the first time, so we could run all speaker on the same amp. We used an RPi (running Roon endpoint SW) for each speaker set feeding digital signal (USB to AES/SPDIF) to a fully digital (in and out) BSS BLU160 and then via an Okto DAC8 DAC to the Lyngdorf. All controlled by a Roon master unit on an iPad. Music from Tidal and Qobuz. Neat

I have been an advocate for analog amps most of my life. Having had the fortune to try many amps, including digital such, I always came back to traditional class A/B amps. However, it is with a small tear in my eye I now have to confess that the digital amps have cached up and probably surpassed the analog units. The Lyndorf provided plenty of power while regardless of material was completely free from distortion. Almost too clean, if there is such a thing. Pure High Fidelity.

To be able to compare these very different speakers, we tried to equalize the bass output meaning reducing it on the bigger speakers using REW and a good measuring microphone in the room. We also set the level at listening position at the same level. Sweetspot was averaged over 3 seats in the couch.

Then the feast began. We played all sorts of material and being able to shift speaker in real time was really an interesting experience. Surprisingly the sound timbre is reasonable similar but the compression drivers do deliver a sound that is experienced as “cleaner”.

The big surprise was the 708i’s that really had some big shoes to fill but did so surprisingly good. They are really exceptional speaker for the size and price.

I do of course have a strong bias in that I’m used to the sound of my standard system. It did take some listening to get to grips with that. The feedback from the others is much more valuable in that they did not have that specific bias, albeit they came from excellent systems (M2, K2 aso) with a bias for them.

At the end of the day and after spending the following full day at the show, yes I know that you cannot direct compare different rooms/music aso, I’m please to note that all held the 4367M as good as the best in the show, or potentially better. We did spend some time with the 4367M’s the same day after the show to compare. Maybe the guests were just being polite…

However, after countless hours the 4367M clones are now officially finished. My personal view is that using a DSP combined with large format driver provides for a lower XO which the 4” delivers on in a way I don’t see in the original version.

I also think the 4367 wave guide is easier to integrate in a residential room than many other horns. I like piano and to my ears the 4” does really shine there. -And on deeper voices. With good material the speakers disappear, only music remains. Odd experience.

I have no idea if that is due to the driver, my reasonable sturdy cabinets, the passive vs active XO or anything else but after having had the luxury to spend some time with 4367 original on several occasions my clones have by no means destroyed that concept.

If there are any improvement that is in the behold of the listener, but for me I choose to believe that is the case.

I’m done. I’m home.

Kind regards
//Rob

PS thanks to the friends helping out trough the process and especially member “Beatelund” who made this day possible. An understanding wife also helps.

[DerekTheGreat]

Hi all,

I have now had the 4367M (M for Modified 😊) operational for some time and had the chance to develop some quasi anechoic and in the room DSP curves. The room is pretty ok except for a nasty modal at about 30Hz. The curves are nice and smooth from about 30hz to 20k. Even phase looks decent...

...I was happy.

Now that is of course not enough so a few days ago I invited some seasoned JBL friends for a shoot-out. They all have trained ears and excellent systems at home...


I'm deathly afraid of this haha... I love my system, yet there's this itch to share it with others and gain feedback. I expect they would tear it to pieces... :flamed:



...Kind regards
//Rob

PS thanks to the friends helping out trough the process and especially member “Beatelund” who made this day possible. An understanding wife also helps.

That helps immensely! I wouldn't have the audio system I love so much if not for her. She was right there with me loading and unloading empty cabinets and then stuffing drivers in there as well as sitting in a chair to comment on the adjustments I was making to the sound. :bouncy:

[Robh3606]

Hello Rob

Thanks for posting this. What a line up! Glad you are enjoying your speakers they look great!

Rob :)

[Mr. Widget]

Hello Rob

Thanks for posting this. What a line up! Glad you are enjoying your speakers they look great!

Rob :)+1

Very cool comparisons, thanks for sharing.


Widget

[pos]

They look absolutely stunning, congrats!
Are you going to change your amplifiers?
Have you considered some of the new headphone amps for the compression drivers? 16 ohms is pretty easy to drive for these, and they have plenty of power (well, a few watts, which is plenty for home use in an active system).

[srm51555]

Thanks for the report. Always love to hear about your projects. Only wished you lived closer

[sebackman]

Thank you for the kind words. Its been a fun and humbling journey.

I'm pretty happy for now. I think the odd experience that they kind of "disappears" when playing good material, indicates that we got it at least reasonable right.

Everyone having embarked on a journey outside established trails knows that it is always scary to evaluate the results. Having swapped in large format Be's in my home brew wall mounted M2 wave guide based builds and others, I was reasonable confident that this was they way for me.

The great technicians at JBL certainly know what they are doing, so trying to improve on an excellent design that is very good out of the box is no simple task. Albeit DSP is cheating a little.

I will try to borrow a pair for original 4367's to compare, but they are not very common over here. That would be very interesting.

I will next fall start looking at upgrading the amps from my bellowed Crown CTS, that are getting rather old by now. So far the really good digital amps (Hypex NCx & Nilai and Purifi) are a little too low on power, but bigger ones have been advertised.

POS, I have had some odd experience mixing amps with different gains and sometimes not identical timbre (not better or worse but audible slightly different) so I don't want to mix amps even if it will be crazy overkill to have a high capacity amp to the drivers.

The reasonable small pricing difference compared to the cost of the build and the time invested does not warrant using a mix of amps. If anything it will be two digital stereo amps. Or potentially two SOTA Benchmark AHB2 class AB amps, but they are really toooooo expensive. But very nice. As of now I will keep the two current CTS600 or swap in the two CTS1200 I have in the shop.

Given that no one seem to want the Crown CTS-series for whatever reason, they deliver crazy performance for the price. The topology is not Crown standard but rather similar to the Mark Levinson amps and was indeed constructed by the same individual, from what I have been told directly from Crown. Even the small 600 offers a damping factor of 3000.

For now I will park myself in the couch with a small glass of something and just enjoy.

Recipe and data is of course available to anybody interested here on LHF.

Rock on
//Rob

[mattking52]

Fantastic work, Rob - many kudos to you. Thanks for being willing to share the fruits of your labor as well.



Or potentially two SOTA Benchmark AHB2 class AB amps, but they are really toooooo expensive. But very nice.

I'm running two AHB2 amps in my bi-amped 4344 setup - I can't say enough good things about them. They are expensive, but as I'm sure you know, they often come up on the used market for much more reasonable prices. I bought one used and one new (before their latest price increase), and if I had been a bit more patient, I probably could have found another lightly used silver-faced unit at a lower price.



I have had some odd experience mixing amps with different gains and sometimes not identical timbre (not better or worse but audible slightly different) so I don't want to mix amps even if it will be crazy overkill to have a high capacity amp to the drivers.


I had been mixing amps in bi-amped applications before, with the goal of combining their "best attributes" in the different frequency bands and had weird results just as you mentioned. The gain differences are a solvable problem to an extent, but John Siau from Benchmark mentioned somewhere on the web how the phase response of the differing amps in a multi-amp speaker setup can create issues at the crossover points, which made a lot of sense - I'll have to dig up the link.



For now I will park myself in the couch with a small glass of something and just enjoy.


You deserve it!

[pos]

I have been using an nc400 for the woofer and a THX789 for the compression driver.
This is by far the best amp combo I have ever used and the best sound I was able to get on the M2.
The THX789 has different gain settings on the front so you can leave the volume control at max position measure your gain from there.

I don't think there should be any problem mixing good amps. If you get a different magnitude or phase response around this kind of crossover region then there is a serious problem with one of the amps.

Anyway, throwing in more watts than needed is not a problem either, as long as you don't hear noise through these sensitive compression drivers, or risk too much watt in case of a crossover failure/mistake.

[sebackman]

Hi all,

Pos, I agree that is a very good combination. You can certainly match amps like you are suggesting and I'm probably lazy to want them to match out of the box. You did carefully pick yours, as you do with knowledge, but I have seen/heard combos that did not work well mixing amps.

I guess using the same amps removes one issue from the equation, you don't have to match/check every time you do a change.

I heard that both Hypex and Purifi are launching higher amperage units come this summer. I will wait for that. And for prices to come down. For now the CTS's will do.

Pos, will send you the 4367 curves and would love for you to take a look at them and see if a FIR could be designed. I'm running a BLU160 in stereo use so we should have enough firepower.

Have nice weekend
//Rob

[pos]

Pos, will send you the 4367 curves and would love for you to take a look at them and see if a FIR could be designed. I'm running a BLU160 in stereo use so we should have enough firepower.
Sure, I'm looking forward to that!