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Ian Mackenzie
07-21-2006, 02:06 PM
Bo,

I agree and as you know I have heard and compared the 5234 and the Ashly with you. In your room there is certainly merit in having carefully prepared Eq.

Either way its a system that turns heads.:)


It will be interesting review your comments in due course when the updated 3145 crossovers are fitted. I reackon you will be stuck on the bar stool for hours!!

I am not sure if you understood my earlier post regards your 12 db filter slopes. Are they -3 db at 290hz?

Ian

boputnam
07-21-2006, 02:31 PM
I am not sure if you understood my earlier post regards your 12 db filter slopes. Are they -3 db at 290hz?Spaced on it...

I have not yet measured these - will do so. This is the voltage drive we forwarded to Bryston - looks like it's -3 to -5dB at 290Hz...

Ian Mackenzie
07-21-2006, 03:45 PM
Okay thanks.


What I was referring to earlier was this quote and it took ages to locate in an old email. Its seems the reference was to the 4343 and its evolution to the 4344. I think this was discussed in one of the many 4343 threads.

As to the exact course of events I am not entirely sure but I think the reference (1) is in respect to the 4343 crossover cards that were set up to reduce a bump at the crossover point as a result of mutual coupling of the woofer and mid cone. As I recall the crossover point is in the order of 5-6 db down.

However, was we know the 4344 was a take off the 4345 and used identifcal crossover network with the exception of the 2235H woofer and it inherited the same active crossover requirements which are stated as 290hz 18db external in the tech spec sheets.

(1.) The slope on the original 4343 was 12 db but they modified the spacing of the frequencies for 230 and 280 hertz, then updated to 18 db 290 hertz in the 4344. The net results is about the same and 18 db is easier to implement.

Reference (2) elaborates and articulates the reasons for certain crossover parameters. So in effect Bo you are correct in that in the purist sense of thw word the approach of emulating the tailored passive crossover (320hz) voltage drives is ideal. I just wonder what difference there would be between that ideal and the 18 db slopes at 290 hz?

I know my self I find the active system more touchy to get the actual balance right, its more a right or wrong setting while in passive mode the adjustment is more a flavour of mid/bass balance.

When I clear my bench I will have a closer look at this and see if I can set up the active crossover to run tailored 12 db slope mode and compare it to stock 18 db slopes.


(2) Bi-amping, bypassing the input inductor, almost always gives better and tighter bass performance. However, most electronic crossovers have fixed crossover slopes and shapes and our passive crossovers are custom tailored for the response of the specific drivers used. This usually results in more precise acoustic drive parameters. You will note that the specifications call for 290 Hz for the electronic crossover and the passive one is 320 Hz. This was done to get the best response possible from off
the shelf electronic curve shapes.

boputnam
07-21-2006, 04:19 PM
I just wonder what difference there would be between that ideal and the 18 db slopes at 290 hz?Part of me wishes I had opted for this Bryston to have changeable slope - I belabored it, but less crap in the path (particularly switches), the better.


I will have a closer look at this and see if I can set up the active crossover to run tailored 12 db slope mode and compare it to stock 18 db slopes.I'd be interested in your findings.

So far, I'm quite liking this - it's really amazing. The voicing is indeed different in the crossover region. I plan to try and measure the response of the LF roll-off both with the Ashly (-24dB) and the Bryston (-12dB) for grins. This ain't CLIO but we'll see...

Ian Mackenzie
07-21-2006, 05:24 PM
Part of me wishes I had opted for this Bryston to have changeable slope - I belabored it, but less crap in the path (particularly switches), the better.

I'd be interested in your findings.

So far, I'm quite liking this - it's really amazing. The voicing is indeed different in the crossover region. I plan to try and measure the response of the LF roll-off both with the Ashly (-24dB) and the Bryston (-12dB) for grins. This ain't CLIO but we'll see...

Belabored....well I belabore about a lot of things too but I would not loose sleep over it ....

I would be quire surprise if you did not hear adifference going from 24 db slopes to 12.

I tried 24 LR slopes over here on the crossover while musing and learning how to attain 18 db with all those jumpers and it worked alright but it was not as correct sounding as 18 db slopes (Q=1) imho. The 18 db setting definately seemed to voice better so I left it at that as I was going cross eyed at that point..Thanks to Cyclotroneguy for some tips.

I also have a 5235 with stock 250hz 12 db slopes and I compared it too the new active crossover with 18 db slopes and it worked but the mids were squewed with the outputs 180 out of phase but my recollections have faded with the flux of time.

So I will definately work on it for you.

Is this still your room setup?
The curve we have been discussing as I understand it.

Edit: It just occurred to me that the ideal curve taken from the passive voltage drive would probably be another variation from the two curves (so as to avoid any wrong conclusions at this point).

So I will have to measure the passive voltage drive manually on my analyser and them take the data points and work out the curve to the active equivalent...

Ian

boputnam
07-21-2006, 05:39 PM
Is this still your room setup?
The curve we have been discussing as I understand it.Yes. We've shared a "coldie" here...
And, sorta - this is obviously not the 52-5140 card - but the graphed comparison is clearly close...

Mr. Widget
07-21-2006, 05:47 PM
When I was working on my 3155 project with Giskard's help, he posted this: http://www.audioheritage.org/vbulletin/showpost.php?p=6332&postcount=32

It clearly shows the expected ~3dB bump from using a Butterworth filter. I suppose in the "real world" the curve may be quite different due to lack of output from the 2122H.

It is interesting that the factory recommendation was for an 18dB Butterworth filter set at 290 Hz and the GT supplied voltage drive was for a 12dB Butterworth set at 320Hz.


Widget

Ian Mackenzie
07-21-2006, 07:08 PM
Yes it is interesting.


Somewhere in a thread and I dont know where are some Spice generated voltage drives for the full set of filters into respective 8 ohm loads.

That may shed more light on this discussion.

I might look for that later on.

If you have a copy of Vance Dickasons Cookbook on page 90 (4th edition) there is very interesting paragraph on the combined response o even order filters....

In short when even order filters are combined the two sections sum flat when the level of both filters is 6 db down at the crossover point.

Normally they are -3 db down at the crossover point for Butterworth filters when phase of high and low pass filters is coincident and the summation is +3db which is +6db gain at the crossover point (+3 minus -3 is 6 db ).

As Dickason points out though if the in phase relationhip is relaxed and the crossover points are spread by a given facter of about 1.3 the filter will sum nearly flat when both high and low pass filter sections are -6db down at the crossover point.

It would be interesting to measure this in practise.

Ian

Mr. Widget
07-21-2006, 08:24 PM
In short when even order filters are combined the two sections sum flat when the level of both filters is 6 db down at the crossover point.

Normally they are -3 db down at the crossover point for Butterworth filters when phase of high and low pass filters is coincident and the summation is +3db which is +6db gain at the crossover point (+3 minus -3 is 6 db ).

As Dickason points out though if the in phase relationhip is relaxed and the crossover points are spread by a given facter of about 1.3 the filter will sum nearly flat when both high and low pass filter sections are -6db down at the crossover point.

It would be interesting to measure this in practise.Linkwitz-Riley filters are -6dB and the sum to a flat on axis output... here is an interesting interview of Siegfried Linkwitz in Stereophile. Look at the middle of this selected page for a discussion about this topic:

http://www.stereophile.com/interviews/503/index3.html

I am not sure how accurate DEQX is in it's emulation of L-R and Butterworth filters, but I have found that the L-R filters sound and measure better. When I have compared the same slope and frequency on Project Widget and measured them with CLIO.


Widget

Ian Mackenzie
07-21-2006, 10:56 PM
When Bo started talking about this I was wondering this they were LR , pure or modified Butterworth filters as I mention above fitted to the Bryston.
If you were keen it would be interesting to test out these various types of filters on the fly with the DEQX plugged into Bo's system.

At any rate it would seem the stock 3145 passive filters were almost entirely empirically tuned and probably with an eye for flat on axis response.

I do like the approach of using Allpass (3rd order fiters) throughout the network.

For those not familiar Allpass filter have an Allpass Phase characteristic. At a basic level what this refers to is the phase relationship (correlated and uncorrelated) of the highpass and low pass filter sections where phase is a function of the filter slope and Q. All odd order networks exhibit and high and low phass phase relationship that constantly 90 degress out of phase and this is termed phase quadrature (no The Who is not invent this term!).

Because the outputs are 90 degrees out of phase at all frequencies the phase is said to be uncorrelated, and the filter outputs will sum together flat when the level of both filters is -3 db at the crossover point. The advantage of the 3rd order filter is that it sums with a flat magnitude response and it attenuates the output of the driver quickly in the stop band. Second and Fourth order LR filter also belong to the Allpass Group of filters, however as Mr Widget indicates, they are -6 db at the crossover point and also provide flat magnitude response.

The distinction between the Third order Butterworth filter and the Second order LR filters as Allpass filters beyond this discussion becomes more complex when we start to look at what is termed Power Reponse.

Power response refers to the off axis amplitude response in the crossover region when we are talking about the distinction crossover filters. Second order LR filters (even order) which sum flat when their high and low pass outputs are -6 at the crossover point do not have a flat power response but have a dip of -3 db at the crossover point. Odd order filters however which have an uncorrelated phase response on axis response and have a flat power response.

The audible differences of these various filter types is depeds on the specific design of the loudspeaker and is open to wide debate.

Ian Mackenzie
07-22-2006, 07:41 AM
Might be a good idea if this whole filter thinghad its own devoted thread with a link from here and from the 4345 Club thread.

These sort of discussions are a myar and can drag on endlessly.

I was about to roll out the self powered 2405 crossover thing being a Greg Timbers recommended 43XX modification and I would like to maintain continuity. If there is anything conclusive regards alternative active filters we can paste them back in here.

Ian

Ian Mackenzie
07-22-2006, 07:47 AM
Doods...

I wish I had reason to travel to Reno...!!

.

Bo,

Might be a useful opportunity for you and Ed to cross paths.

I know Ed spends time in the Bay area, suggest you send Ed a pm as a courtesy.

Ian

boputnam
07-22-2006, 11:04 AM
At any rate it would seem the stock 3145 passive filters were almost entirely empirically tuned and probably with an eye for flat on axis response. Giskard told me it was a very iterative process. They would start with a planned topology, listen, tweak, listen some more and tweak some more.

Ian Mackenzie
07-22-2006, 02:23 PM
Yep,

I got the same impression in that email about the box tuning..quite amazing. I impresses me that it was not done with a computer model. They obviously have great ears!

Ian

Ian Mackenzie
07-24-2006, 10:07 PM
Bo,

Have you done any more comparions or A/b's ?

I am assembling another project for my system so I won't have any feedback on the filters for 2-3 weeks

Ian




Giskard told me it was a very iterative process. They would start with a planned topology, listen, tweak, listen some more and tweak some more.

Ian Mackenzie
07-30-2006, 05:15 PM
Some parts arrived so I should be able to start on this project soon.

The bags of capacitors are polystyrene, hard to get but excellent for signal filters.

Ian

Ian Mackenzie
10-03-2006, 10:05 PM
Re: Active Crossover / External Auricap Crossover/4344 Review (True Love)
Hi, Ian. I got the active crossover back from Bo last Friday. I don't think he ever had a chance to audition it. I reinstalled it in my system on Sunday. I've got to tell you that after not listening to my 4344's (can I call them that now?) for the last two months, I am just utterly blown away. The system sounds so damn good. Just absolutely amazing. I think I had been making so many improvements over the last year I had started to take the system for granted. But after listening to my other JBL's for the past two months (Performance Series, 240Ti's, 120Ti's, 4412's) and then coming back to these, I realize just how special these are. Full, rich, articulate sound that can't be fully duplicated by the smaller boxes. It's like meeting up with an old love and remembering why you fell in love in the first place. I continue to be amazed. Thank you once again for the sharing your skill in the crossovers.

Ed

Nice to hear you so happy!

Can you post us another picture please mate?

Ian





I’ve been invited by Ian Mackenzie to publish an outline of the upgrades that I’ve made to convert my 4343’s to 4344 spec. And give my impressions of the resulting sound. This 2 ½ year upgrade process has culminated with the recent addition of custom built active and passive crossovers built specifically for my application by Ian. A summary of these upgrades are as follows. For more description and detail of these upgrades you’ll want to drill back through the 4343-to-4344 Upgrade Discussion thread.

Upgrade 4343B drivers to 4344 spec.
1. Replace LF 2231H drivers with 2235H
2. Replace MF 2121H drivers with 2122H
3. Replace HF 2420 compression driver with 2425J.

Bi-Amp speakers:
1. Pass Labs 250w/ch Class A amp for LF drivers
2. Pass Labs 150w/ch Class A amp for MF-HF-UHF drivers
3. Ashly XR-1001 2-way active crossover

Upgrade stock passive crossovers:
1. Outboard crossovers custom built specifically for 4344 application by Ian Mackenzie.
2. Outboard crossover design completely bypasses the 4343’s Bi-Amp switch
3. Outboard crossover design completely bypasses the 4343’s L-Pads

Added internal Brace

Upgraded active crossover:
1. 2-way active crossover custom built specifically for 4344 application by Ian Mackenzie

Evaluation of upgrades.
1. When I upgraded from the 4343B to the 4344 drivers the changes were subtle. The low frequencies now seemed a little more detailed. The mids seemed to sound more natural and the highs seemed to be much more extended and natural (although I should add that some readers have said they prefer the aluminum diaphragm in the 2425H).

2. Bi-amping the speakers added quite a bit of detail and authority to the low end. I had issues though that I attributed to the Ashly active crossover (or possibly the internal Bi-Amp switch or a combination of the two). What I gained in detail and authority on the low end, I gave up in terms of transparency and fullness of the music from the mids on up. The music sounded somewhat thin and undynamic. It seemed like the music was veiled. I described the sound to be as if there was something in between me and the speaker. I could still hear the music but it just wasn’t alive. I went back to a single amp set-up to verify it was the Ashly crossover/bi-amp switch causing this. I eventually decided that bi-amping was still the way to go and so went back to the bi-amped set up and started looking for a better quality active crossover.

3. Adding in the custom built outboard passive crossovers, eliminating the internal bi-amp switch and L-pads, and adding the internal bracing was all done at the same time. While it would have been ideal to listen to the differences after each of these upgrades separately, it wasn’t practical to do so. But taken together, and probably due in most part to the new passive crossovers, they allowed the music to open up and be more full and transparent. The speakers sounded better than they ever had before. Even though there was still some slight veiling effect from the Ashly crossovers, it appeared to be minimized.

4. It’s been a little over a month since I upgraded the active crossover to the custom active crossover Ian built specifically for my application. See pictures below active crossover. What you don't see is that the power supply is oused in a complete differen box and is hidden behind the equipment cabinet. Adding in this active crossover was another quantum leap forward. The veiling caused by the Ashly switch was now completely gone. And there was huge increase in detail from top to bottom. There was an overall new transparency and fullness to the music. The low end had a huge increase in control and authority of the bass. The mid through highs were now so crystal clear that any imbalance between drivers immediately stood out. It took me several attempts to get the balance amongst the drivers correct but once I did, the music became jaw-dropping good. It was detailed and dynamic. In fact it became hard to stop listening because it made all the old music I’d heard hundreds of times before, fresh and exciting again. I found subtle nuances I hadn’t noticed before because the detail just wasn’t there before. I still am amazed at how good it sounds when I turn on the music after being away for awhile. It’s nothing short of awesome. The music is now full, dynamic and detailed.

It's taken over two years to get to this point but this latest upgrade has made the whole upgrade journey worth it. I can't over emphasize the importance using good quality crossovers. The quality of your crossovers should be at least equal to the quality of your other components. Really the easiest part was sourcing and installing the 4344 spec drivers. The most challenging part was upgrading the crossovers. You can use the stock 4343 crossover temporarily, but it was never designed for the 4344 drivers. And if you can find a 3145 network out there chances are it's time for it to be upgraded anyway. So invariably you'll be faced with having to custom make or if you have the time and expertise to do so. I had neither, so I was fortunate to have Ian custom make the crossovers for me. I asked Ian for his help because he understood the amps I was using and could match the quality of the crossover components to them. But there have been several LH threads written on building crossovers and there are several Forum members that have the ability to custom build networks. My deepest thanks go out to Ian for his patience, persistence and technical wizardry in building these phenomenal crossovers. It's hard for me to imagine how the music can sound any better. Although I have heard Ian's currently toying with the idea working on incorporating a small Pass DIY amp into an active crossover chassis to run the UHF-2405's. Sounds interesting.

porschedpm
10-03-2006, 10:48 PM
It'll take me a day or two but I'll take some pics and get them posted.

Ed

Mr. Widget
10-03-2006, 10:54 PM
Have you tried switching back and forth between the 2420s and the 2425s?
If your 2420s were up to spec, I'd expect you'd find them a bit less aggressive sounding yet retaining all of the detail.


Widget

Ian Mackenzie
10-04-2006, 05:02 PM
Having spent counltess hours stuffing around with nine volt batteries I will now focus on this project. I have a populated board, heatsink and PS. All that is required is the 18 db slope filter.


Hope to post some details soon, it should be fun.

That why we are all here.

Ian

http://www.audioheritage.org/vbulletin/showpost.php?p=118891&postcount=266

Ian Mackenzie
10-07-2006, 02:48 PM
Have you tried switching back and forth between the 2420s and the 2425s?
If your 2420s were up to spec, I'd expect you'd find them a bit less aggressive sounding yet retaining all of the detail.


Widget

All JBL's are aggressive one way or another.

I've never been one for Black Art but I think that aspect was exploited with the 4430/35 and the whole diamond surround thing. JBL wanted something exciting and different with more zing . I am told the Alnico 2405 is also different to the 2405H. I dont know the details but the alnico's would appear to have more 2nd harmonic distortion but low 3rd.

I use 2420's myself and I quite liked the titaniums brilliance, I also use the alnico 2405. The coated acquaplas titanium is more mellow and refined. Great for classical and acoustic but if you are rock freak you might prefer plain titanium. With the more linear systems like the 4344 it tends to be a mute point because you can massage the overall balance..unlike a 2 or 3 way.

The 2307/308 assembly tends concentrate the luminous nature of the titanium. Because of this any noise or distortion artifacts can get muddled with the diaphragms natural resonances above 3000 hz and this is why crossover component and amplifier selection is more critical. The symptom is the sea shell effect. Aquaplas coating effectively damps and controls the diaphragm so this becomes much less of an issue.

I might buy some 2425 and try my plain titanium just for grins.

Ian

Ian Mackenzie
10-15-2006, 05:38 AM
News:

http://www.audioheritage.org/vbulletin/showpost.php?p=129259&postcount=194

porschedpm
10-15-2006, 07:12 PM
As promised here's a pictures of the active crossover, built by Ian. The second picture shows the rest of the components which make up my main system, from bottom: Pass Labs x250 amp; Pass Labs x150.5 amp; McIntosh C42 preamp; Sony DVP-S9000ES DVD player; Sony RDR-GX7 DVD recorder; Ian's Pass DIY v2005 Active Crossover; Sony SAT-T60 satellite receiver/Tivo.

porschedpm
10-15-2006, 07:22 PM
Here's pictures of the entire system including the outboard passive crossovers Ian built specifically for the 4344 driver set, which I've converted my 4343's to. These crossovers usually are tucked out of sight behind the speakers. Also seen is a Velodyne ULD-15 subwoofer and its servocontroller.

Ian Mackenzie
10-15-2006, 09:31 PM
Ed,

Thanks for the pics. Awesome. Talk about the house of JBL & Pass!

I really like the cabinet too, nice.

As I understand it this is your main system.

Can you comment on how it compares with your other JBLs now that you have had the system back running for a little while given your impressions posted earlier.

Is that Nature channel?...tell me they aren't kangaroos!

Ian

porschedpm
10-16-2006, 12:37 AM
......As I understand it this is your main system.

Can you comment on how it compares with your other JBLs please?

Is that Nature channel?...tell me they aren't kangaroos!

Ian
No, those aren't kangaroos, they're Meerkats. From the series on Animal Planet called "Meerkat Manor".

It's really not fair to compare this system to any of my others because this is the system I've strived to make my reference system. This system is much better than my others at filling the entire room with rich, detailed and full-bodied music. And it does it with authority. But at the same time these are probably the warmest sounding solid state amps I've heard, especially with acoustic instruments and female voices.

The closest comparison I have is a Home Theater system set up in the living room using a Tag pre-pro, a Bryston 150w x 5ch amp, a McIntosh MC-300 amp, Performance Series PT-800/PS1400 combos for the fronts, two XPL200's for the sides, two XPL90's for the rears, a S3HC for the center and a PS1400 for the sub. The power to fill the room with sound is there, without a doubt. And it all sounds very good but it's just a bit dryer and more analytical. Don't get me wrong though, if I didn't have my 4344 system, I would be very content with this system.

In my Apt/Home Office in the Bay Area, I have a pair of 240Ti's hooked up to a Cary 15w/ch tube integrated amp. This system is set up more as a lower volume, near field system with the 240Ti's about 15 ft apart, elevated and both pointing towards my desk and office chair in the middle. In this configuration they sound phenomenal. But they wouldn't be able to keep up with the 4344's in terms of filling the room with music. If I hooked up the 240Ti's to the Pass Labs X250 though, they'd probably put up a good fight. But in the end their lack of a horn and a mid-bass speaker would put them at a disadvantage.

My other systems are comprised of various combinations of 4412's, 120Ti's, and 18Ti's, all of which sound great for their intended purposes (bedroom, garage, RV, etc.) but none of which even come close in comparison to the 4344's.

Ian Mackenzie
10-16-2006, 02:15 AM
The closest comparison I have is a Home Theater system set up in the living room using a Tag pre-pro, a Bryston 150w x 5ch amp, a McIntosh MC-300 amp, Performance Series PT-800/PS1400 combos for the fronts, two XPL200's for the sides, two XPL90's for the rears, a S3HC for the center and a PS1400 for the sub. The power to fill the room with sound is there, without a doubt. And it all sounds very good but it's just a bit dryer and more analytical. Don't get me wrong though, if I didn't have my 4344 system, I would be very content with this system.

In my Apt/Home Office in the Bay Area, I have a pair of 240Ti's hooked up to a Cary 15w/ch tube integrated amp. This system is set up more as a lower volume, near field system with the 240Ti's about 15 ft apart, elevated and both pointing towards my desk and office chair in the middle. In this configuration they sound phenomenal. But they wouldn't be able to keep up with the 4344's in terms of filling the room with music. If I hooked up the 240Ti's to the Pass Labs X250 though, they'd probably put up a good fight. But in the end their lack of a horn and a mid-bass speaker would put them at a disadvantage.

My other systems are comprised of various combinations of 4412's, 120Ti's, and 18Ti's, all of which sound great for their intended purposes (bedroom, garage, RV, etc.) but none of which even come close in comparison to the 4344's.

Ed,

Thanks for the elaboration on the finer points your system(s) but your making the rest of us feel poor!:D That's probably because we are!

I am intrigued with your comments about the rich, detailed and full bodied presentation of the main system.

I think that is certainly a desirable quality on a powerful system as you can turn it up and enjoy it!

In my experience I have found Passlabs Aleph series certainly quite engaging and warm while my X250.5 is quite neutral and tonally revealing of the source and more dynamic in my own system. I imagine the voicing of your X150.5 is very similar being a somewhat scaled down version of the X250.5

The way the X250.5 renders the natural timbre of instruments is the most spectacular aspect of the improved X0.5 Series to my ears.

Getting back to your impressions when I was tuning the system down here it became apparent that there was a certain detailed, yet rich palpable quality and the harder you drive it the better it gets.

Every system has a sweet spot and these loudspeakers and amps like to be driven to realistic levels. That is when they really sing and sound their best.

I would suggest the JFets in the active crossover have if anything a certain natural detail but sweet quality and the Auricaps in the crossovers are anything but cold and tend to be regarded as a paper and oil capacitor in smoothness and naturalness but without the colourations of paper and oil capacitors. This is why they are an industry reference.

But as we have said before its the blend and melting together of the whole system that makes it work but I am pleased it has worked out the way it has.

Ed, it would seem you have chosen your systems well and each has its own special quality. We appreciate the time you have taken in your busy schedule to post the above paragraphs.

Enjoy.

Ian

Ian Mackenzie
07-29-2007, 03:28 AM
http://www.audioheritage.org/vbulletin/showpost.php?p=178773&postcount=8

An interesting upgrade of a stock JBL crossover.

In another thread someone posted why are there so any discussions about upgrading the 4343 and so few about the 4344.

http://www.audioheritage.org/vbulletin/showpost.php?p=178646&postcount=1
http://www.audioheritage.org/vbulletin/showpost.php?p=178648&postcount=2

It woud be nice to hear from more 4344 original owners but I think most of those systems reside in Japan.

I still think they are one of the most fun and satisfying JBL Classics. If you don't have the space for the larger JBL 4345 the 4343-4344 is right there.


http://www.audioheritage.org/vbulletin/showthread.php?p=178550#post178550

There has also been a lot of discussion recently about upgrading diaphragms and alternative compression drivers. That suggests to me there is a lot of untapped mileage left in these vintage systems.

Ian

alskinner
07-29-2007, 08:41 AM
I have to agree with Ian. The Auricaps are by far the most natural sounding capacitors I have run into. I have been working on my 4344/4345 passive crossover off and on for 2 years. Originally used Solens but in the passive they were too analytical with a loss of timbre and natural tone. The Auricaps for me have a great natural sound to them. I have just about got all the prototyping finished and will start constructing the final version of my hybrid 4344s soon.

Ian Mackenzie
07-29-2007, 02:43 PM
Hi Al,

Thank for the report. Please post some pictures when you are ready. Juicy crossovers always make great pictures


Ian

OLDGEN
08-11-2007, 09:16 AM
I have bought 6 hours before, I have loaded my drivers ( the originals must repair first)

Chas
08-11-2007, 02:39 PM
I have bought 6 hours before, I have loaded my drivers ( the originals must repair first)

Looks like you're in, baby! :yes:

Welcome.

Andyoz
08-11-2007, 07:33 PM
I have bought 6 hours before, I have loaded my drivers ( the originals must repair first)

Anyone that uses a pair of Tannoy's as JBL 4435 speaker stands has earned their place..:)

27297

mbd7
08-12-2007, 06:20 PM
Welcome aboard. Since you've got these speakers on rolling carts (it'll be easy to move them) and having them in such close proximity to each other you definitely want to exchange the positions so that the 2405 "slot" super-tweeter is on the "outside" of the speaker configuration.

Texas... it's just not a state... it's a state of mind.

alskinner
08-25-2007, 01:18 PM
Per Ian's request, attached are pics of the 4344/45 crossovers. The LF and MF are based on the original 4345 schematic using Air Coils with Solen caps with .01 audiocaps in tow. The HF and UHF are based on one of the equivalent designs that Giskard came up with. The Auricaps on the upper end make a world of diffirence to me in tonality, and timbre. The Solens I originally used in the HF and UHF sounded way too sterile for my tastes.

Regards
AL

Ian Mackenzie
08-25-2007, 01:40 PM
Al,

Beautiful!

Nice to see some pics of your handy work.

Ian

alskinner
08-26-2007, 01:42 PM
Ian,

Thanks for the kind words. Getting these crossovers to the state their in now gives me a deep respect for people like Gregg Timbers and the amount of work that goes into getting them right. I can work out the voltage and frequency dividers, but that still doesn't mean they will necessarily sound right. As I have found the components used have a lot to do with the sound. I couldn't believe at first the difference in the Auricaps as compared to the Solens in the sound. IMHO the Auriacaps can't be beat in a total passive crossover. I still haven't made up my mind whether to leave the 2421s with the 2309 horns in or go with my Westlake clones with the 2441s. I really like the sound of the Westlake style horns but I will need to modify the crossover slightly bringing down the frequencies between 1K and 4K about 2 decibels. At any rate it's been awhile since the 4344 clones have made me smile from ear to ear.

Regards
AL

Ian Mackenzie
08-26-2007, 02:15 PM
Al,

I assume you are referring to charge coupling the Solens?

Ian

alskinner
08-26-2007, 02:51 PM
Ian

Right. The Solens do quite well in a charged coupled crossover. I just couldn't get them to sound right in a total passive configuration. Of course this is just my opinniion and others may have a different take. That's one reason I don't post as often as I should. What works for me may not be someone elses cup of tea.

AL

Ian Mackenzie
08-26-2007, 03:03 PM
Al,

The usual disclaimers are always appropriate.

On that note can you decribe your system configuration and other equipment.

It was rather nice as I recall.

Ian

alskinner
08-26-2007, 03:47 PM
The 4344 system consists of the crosovers pictured and the standard driver compliment 2235H, 2122H, 2421 and 2309 horns and athe 077/2405 tweetrers. As pictured above I have experimented with the Westlake style horns with 2441s and the 076/2403 tweeters. Although the standard 4344 compliment is excellent, I am leaning towards Westlake style horns and 076 as the final product. Again this is a personal preference as there is something about the Westlake horns that gel with the rest of the system that I can't get the 2421s to quite do. I have 3 pairs of 2122s as for me it is hard to find a mid bass that will do what they do best especially geling the vocal range between them and the horns. I am using my trusty Threshold Stasis II to power with and a set of 4400 white crossovers. With the system as it is I use very little equalization except as stated earlier when I am runniing the Westlake horns I find the need to lower the range between 1K an 4K about 2 decibles.

Al

Ian Mackenzie
08-27-2007, 02:43 PM
Al,

Very nice. Excellent choice of equipment.

I take it the WAF factor is better with the Westlake style horns than those in your avatar!

The thing I like about this is your getting the sound you want by gradually working on it over a period of time and its not broken the bank.

Ian

alskinner
08-28-2007, 04:56 PM
Ian,

As you know, the 4344/4345 can be some of the best sounding speakers out there. But as stated elsewhere they are not plug and play. Careful consideration of the cabinet construction, crossovers and yes equalization is important in getting them to sound and perform correctly. I have never understood some folks that are against using equalizers. When used wisely they can help with room corrections. If I remember correctly most studios that used the the big JBL Monitors used equalization with room treatments along with careful RTA measurements to get the optimal sound out of these systems. Having said that poorly made or implemented equalization can have the opposite effect. To me the White's are some of the most natural sounding equalizers out there. I think this may be one of the reasons JBL bashers exist. I bet most of them have never heard a properly tuned and equalized set.

Along with this the rest of the signal chain has a great effect especially amplifiers. As a great admirer of Nelson Pass's work they for me fit like a glove with the big monitors. Although I enjoy of the Stasis II, I am setting my sights on a Pass 250.5, as I have heard nothing but good things about it.

I believe the 4344/4345 have potential that will go on for years to come. As knowledge is gained in the areas of crossover design, the can only get better and better.

As far as my avatar, I am also a fan of the 2360 horn, although not as articulate as the 4344s it has a special appeal all it's own. Bu t I don't want to get off topic.

I am very fortunate to have a great understanding wife, that supports my hobby. She has been great listening for over two years as the project has come together. She is brutally honest, if it sounds like crap she'll tell me. But in there present form she enjoys listening to them as much as I do.

AL

Ian Mackenzie
08-29-2007, 02:53 PM
Nice post Al.
http://www.audioheritage.org/vbulletin/showpost.php?p=183239&postcount=7

I posted this this morning and mention it here as there is relevance to the upgrade of the 4343.

This post will possibly be moved in which case I will attach a word doc to this thread at some point on a home user guide of the 4 way monitors.

Ian

Ian Mackenzie
12-11-2011, 12:38 AM
Following the recently closed thread on Cable Busters please find below a summảry of links to some aspéct of ủpgading the 4343 monitors.

Note in fact an 8 pole speakon connector and Cảrdás Binding posts following consideration for updating the entire system.

Thẻ complexity of the project being beyond that of most users


http://www.audioheritage.org/vbulletin/showthread.php?6633-Discussion-Thread-JBL-4343-to-4344-upgrade&p=69854&viewfull=1#post69854 (http://www.audioheritage.org/vbulletin/showthread.php?6633-Discussion-Thread-JBL-4343-to-4344-upgrade&p=69854&viewfull=1#post69854)
If you do plan on an external network you will need to arrange a suitable means of cabling to the outside world. I used an 8 Pole Speakon Plug and Socket. There a several advantages with this style of connector, its air-tight, has very good electrical characertistics, takes a 13 gauge cable and the polarity of the individual driver cabling is identified and maintained without fear of error.
http://www.audioheritage.org/vbulletin/showthread.php?6633-Discussion-Thread-JBL-4343-to-4344-upgrade&p=75219&viewfull=1#post75219 (http://www.audioheritage.org/vbulletin/showthread.php?6633-Discussion-Thread-JBL-4343-to-4344-upgrade&p=75219&viewfull=1#post75219)
http://www.audioheritage.org/vbulletin/showthread.php?6633-Discussion-Thread-JBL-4343-to-4344-upgrade/page12

http://www.audioheritage.org/vbulletin/showthread.php?6633-Discussion-Thread-JBL-4343-to-4344-upgrade&p=76308&viewfull=1#post76308 (http://www.audioheritage.org/vbulletin/showthread.php?6633-Discussion-Thread-JBL-4343-to-4344-upgrade&p=76308&viewfull=1#post76308)

http://www.audioheritage.org/vbulletin/showthread.php?6633-Discussion-Thread-JBL-4343-to-4344-upgrade&p=102142&viewfull=1#post102142

rwwear
06-07-2020, 05:28 PM
Upgrade 6 – Upgrade drivers to 4344 spec.

1. Replace or recone LF drivers to 2235H

2. Replace or recone MF drivers to 2122H

3. Replace or rediaphragm HF compression driver to 2425J.


1 Well I have discussed that to death above.
2. The 2122H is an upgrade of the 2121 and according to Giskard and others a better driver.

Here are a number of links that will answer all your questions and more!

http://www.audioheritage.org/vbulletin/showpost.php?p=8486&postcount=11
http://www.audioheritage.org/vbulletin/showpost.php?p=8482&postcount=7
http://www.audioheritage.org/vbulletin/showpost.php?p=7395&postcount=4
http://www.audioheritage.org/vbulletin/showthread.php?t=39&highlight=2122H
http://www.audioheritage.org/vbulletin/showthread.php?t=93&highlight=2122H
http://www.audioheritage.org/vbulletin/showpost.php?p=546&postcount=2
http://www.audioheritage.org/vbulletin/showpost.php?p=53291&postcount=3
http://www.audioheritage.org/vbulletin/showthread.php?t=4379&highlight=2122H
http://www.audioheritage.org/vbulletin/showthread.php?t=751&highlight=2122H
http://www.audioheritage.org/vbulletin/showthread.php?t=3604&highlight=2122H
http://www.audioheritage.org/vbulletin/showthread.php?t=1616&highlight=2122H
http://www.audioheritage.org/vbulletin/showthread.php?t=89&highlight=2122H

3. This is an interested upgrade.

Firstly, if you own a stock 4343 I would think twice about pitching out the 2420 for the 2425J. Some members have reported better sonics from the Alnico 2420/2421.

Secondly, I am not sure if the upgrade to 2121 aluminium diaphragm is still available as a spare part from JBL, I know they are around on E bay sometimes......someone might want to check this out.

Regardless either is better than the original 2420 diaphragm.

The aluminuim version of the diamond surround diaphragm apparently sounds better. If you are really keen you might want to sniff out the aquaplas coated 275nd diaphragms. There might be some technical variations but I think the results would be rather tasty.

The issue with these things is mass, stiffness and self damping....much like any other driver actually.

There are a number of threads that explain how these diaphragms work and so on and so forth.

Please arrange the upgrading of the diaphragm by a JBL authorised service centre. Edgewound is one Authorised JBL service agent I am aware of on the forums although I have not heard much of him lately.


My recommendation is don't do any driver upgrades yourself, just call your local JBL service agent and tell them what you need.


If someone wanted to upgrade their 4343's to 4344's wouldn't be better to upgrade them to 4344 "B's"?

Ian Mackenzie
06-07-2020, 11:36 PM
That thread is over nine years old so things have changed including the availability of recone kits and drivers.

That said l know of 4343 owners who wanted to retain the integrity of the 4343 and on my advice they rebuilt the original 3143 networks using high quality parts and they are exceedingly happy.

I will come back to you later this week with an appropriate response of available options.

rwwear
06-08-2020, 06:09 PM
That thread is over nine years old so things have changed including the availability of recone kits and drivers.

That said l know of 4343 owners who wanted to retain the integrity of the 4343 and on my advice they rebuilt the original 3143 networks using high quality parts and they are exceedingly happy.

I will come back to you later this week with an appropriate response of available options.


I should have said
4344 Mk II.

Ian Mackenzie
06-08-2020, 07:12 PM
That network is specific to the drivers in
that system.

You can plug play but it won't deliver anywhere near the potential of a correctly optimised system.

To me it’s the difference of a wall of sound with the paint peeling of the walls to that which sounds fucking amazing at any volume level. ��.

Why is this? The 4344mk11 crossover voltage drivers have been carefully optimised for the woofer x###, the 2123H, the 275nd and the 2405.

If you connect any old compression driver like a 2425, 2420 or a 2446 to the 4344mk11 network it will go but it will sound odd if you know what a genuine 4344mk11 sounds like. Trouble is people dismiss it as a Japanese model sound. Hence the varying opinions of likes and dislikes of morphed attempts to upgrade these systems. What you don’t know you don’t know and may never know of course but life goes on and eventually you will tire of it and do something else.

The better way is to measure the original system very carefully documenting each drivers response, voltage drive and impedance. Then test and learn the impact of alternative drivers against the original. Attempting this with a PA led bar spectrum analyser, iPhone or YouTube comparisons won’t cut it.

If you look up Giskard various threads he did investigate using the 2123H (as used in the 4344mk11) with some large format boat anchor drivers using the 3155 network. Some people of reported positive results.

rwwear
06-09-2020, 04:10 PM
That network is specific to the drivers in
that system.

You can plug play but it won't deliver anywhere near the potential of a correctly optimised system.

To me it’s the difference of a wall of sound with the paint peeling of the walls to that which sounds fucking amazing at any volume level. ��.

Why is this? The 4344mk11 crossover voltage drivers have been carefully optimised for the woofer x###, the 2123H, the 275nd and the 2405.

If you connect any old compression driver like a 2425, 2420 or a 2446 to the 4344mk11 network it will go but it will sound odd if you know what a genuine 4344mk11 sounds like. Trouble is people dismiss it as a Japanese model sound. Hence the varying opinions of likes and dislikes of morphed attempts to upgrade these systems. What you don’t know you don’t know and may never know of course but life goes on and eventually you will tire of it and do something else.

The better way is to measure the original system very carefully documenting each drivers response, voltage drive and impedance. Then test and learn the impact of alternative drivers against the original. Attempting this with a PA led bar spectrum analyser, iPhone or YouTube comparisons won’t cut it.

If you look up Giskard various threads he did investigate using the 2123H (as used in the 4344mk11) with some large format boat anchor drivers using the 3155 network. Some people of reported positive results.


Ian, can you give your impression of the difference in sound quality between the stock 4343 and the 4344 and 4344MKII? If I planned on turning a 4343 into a 4344MKII, I would attempt to update all of the drivers if possible. I realize it would be almost as easy to just build the 4344MKII's and sell my 4343's. But nevertheless what's your take?

Ian Mackenzie
06-10-2020, 05:10 AM
Ian, can you give your impression of the difference in sound quality between the stock 4343 and the 4344 and 4344MKII? If I planned on turning a 4343 into a 4344MKII, I would attempt to update all of the drivers if possible. I realize it would be almost as easy to just build the 4344MKII's and sell my 4343's. But nevertheless what's your take?

Loaded question...LOL.

Well there are several ways of describing the differences.

Lets look at the first question.

The 4343 has an over arching live presentation. That to my mind comes predominantly from the 2121 10 inch mid cone that has some mild cone break up in the upper mid range and the 2420 aluminium diaphragms which were a bit harsh. The crossover was a first attempt at this kind of 4 way system (not by GT). This could be tempered with a smooth sounding class A amplifier like an Aleph 2 SE 200 watt amplifier by Nelson Pass also popular in Japan or a valve amplifier.

I lived with the 4343 for a long time and I enjoyed it. I also auditioned the 4343 in another forum members home and my impression were similar. It was an excellent loudspeaker for jazz genre. Hence it was well accepted by the Japanese audiophile.

The 4344 is refined in a number of areas. The new 2122H mid cone was smoother improved version of the 2121 mid cone. The 2425 compression driver with diamond surround titanium diaphragm was smoother sounding (the titanium does have a nice presence in the tone that goes well with brass instruments) and the crossover network has better topology. The result was improved driver transitions and improved transient performance. The 4344 Lpads need to be set up very carefully with an accurate measuring kit like REW. Once the pads are properly its the last loudspeaker you will own with the one exception of the model 4345 which was the 18 inch version of the 4344. The 4345 was much larger system. Note the 4344 crossover networks can be rebuilt with better parts like the charge coupled approach resulting in far more transparency. A high quality active crossover will also improve transparency.

The 4344mk11 was introduced in the 1990's. It featured a newer slightly more sensitive bass driver, a newer iteration of the 2122H 10 inch mid cone called the 2123H. This 10 inch mid cane is a bit smoother and a more efficient driver. The 2123H tonality is biased towards a more powder smooth mid range but its not as extended as a mid bass driver. This requires careful crossover transition (see the 4344mk11 network). The 275nd compression driver was new and used in other JBL systems of that decade. it features a lighter titanium diaphragm dusted with acquaplas. This resulted in a slightly more damped presentation making it less live sounding. The horn crossover EQ (tilt) and slopes were revised to optimise the 275nd response curve. The 275nd compression driver runs out full range with a mild rate attenuation above 8000 hertz. The network was fully re worked with a different take on the driver transitions for the critical listener.

My impressions are of a more coherent, smoother and refined presentation which it is if you measure it properly. A bit less JBL house sound (think snappy, chalky cracking transients) to a slightly more mellow hifi presentation. I also found it easier to adjust as the L pads are calibrated +-1.5 db.

To answer your second question.

Yes all at once. Otherwise it gets a bit complicated.
Attempting to clone the 4344mk11 is not straight forward as it requires a dusted one inch titanium diaphragm. A few of us came up diy versions of the acquaplas dusted diaphragms. With some careful tweaking I got the 4344mk11 style of system dialled in nicely.

I would use the 2235H woofer, the 2123H (off Ebay or Jammin Jersey).On the compression contact Ken at http://www.repairspeakers.com for the dusted 8 ohm 2425 diaphragm and see if he can help you before you make plans.

On your third question I think it would be cool to re incarnate a 4343 baffle as a 4344mk11. Making new enclosures is a lot of work.

Pm me if you need further assistance.

BTW those who have time athome and would like a fun project you can build DIY versions of the Pass Aleph quite easily and it won't break the bank. I found the Aleph had great synergy with the JBLs on the mid, horn, slot array when bi-amping. Go to www.diyaudio.com and the Pass Forum and ask about building an Aleph 3 or Aleph 30 (50+50 watts). Alternatively check out www.Audiogon.com

rwwear
06-10-2020, 07:43 AM
Loaded question...LOL.

Well there are several ways of describing the differences.

Lets look at the first question.

The 4343 has an over arching live presentation. That to my mind comes predominantly from the 2121 10 inch mid cone that has some mild cone break up in the upper mid range and the 2420 aluminium diaphragms which were a bit harsh. The crossover was a first attempt at this kind of 4 way system (not by GT). This could be tempered with a smooth sounding class A amplifier like an Aleph 2 SE 200 watt amplifier by Nelson Pass also popular in Japan or a valve amplifier.

I lived with the 4343 for a long time and I enjoyed it. I also auditioned the 4343 in another forum members home and my impression were similar. It was an excellent loudspeaker for jazz genre. Hence it was well accepted by the Japanese audiophile.

The 4344 is refined in a number of areas. The new 2122H mid cone was smoother improved version of the 2121 mid cone. The 2425 compression driver with diamond surround titanium diaphragm was smoother sounding (the titanium does have a nice presence in the tone that goes well with brass instruments) and the crossover network has better topology. The result was improved driver transitions and improved transient performance. The 4344 Lpads need to be set up very carefully with an accurate measuring kit like REW. Once the pads are properly its the last loudspeaker you will own with the one exception of the model 4345 which was the 18 inch version of the 4344. The 4345 was much larger system. Note the 4344 crossover networks can be rebuilt with better parts like the charge coupled approach resulting in far more transparency. A high quality active crossover will also improve transparency.

The 4344mk11 was introduced in the 1990's. It featured a newer slightly more sensitive bass driver, a newer iteration of the 2122H 10 inch mid cone called the 2123H. This 10 inch mid cane is a bit smoother and a more efficient driver. The 2123H tonality is biased towards a more powder smooth mid range but its not as extended as a mid bass driver. This requires careful crossover transition (see the 4344mk11 network). The 275nd compression driver was new and used in other JBL systems of that decade. it features a lighter titanium diaphragm dusted with acquaplas. This resulted in a slightly more damped presentation making it less live sounding. The horn crossover EQ (title) and slopes were revised to optimise the 275nd response curve. The 275nd compression driver runs out full range with a mild rate attenuation above 8000 hertz. The network was fully re worked with a different take on the driver transitions for the critical listener.

My impressions are of a more coherent, smoother and refined presentation which it is if you measure it properly. A bit less JBL house sound (think snappy, chalky cracking transients) to a slightly more mellow hifi presentation. I also found it easier to adjust as the L pads are calibrated +-1.5 db.

To answer your second question.

Yes it it all at once. Otherwise it gets a bit complicated.
Attempting to clone the 4344mk11 is not straight forward as it requires a dusted one inch titanium diaphragm. A few of us came up diy versions of the acquaplas dusted diaphragms. With some careful tweaking I got the 4344mk11 style of system dialled in nicely.

I would use the 2235H woofer, the 2123H (off Ebay or Jammin Jersey).On the compression contact Ken at http://www.repairspeakers.com for the dusted 8 ohm 2425 diaphragm and see if he can help you before you make plans.

On your third question I think it would be cool to re incarnate a 4343 baffle as a 4344mk11. Making new enclosures is a lot of work.

Pm me if you need further assistance.

BTW those who have time athome and would like a fun project you can build DIY versions of the Pass Aleph quite easily and it won't break the bank. I found the Aleph had great synergy with the JBLs on the mid, horn, slot array when bi-amping. Go to www.diyaudio.com (http://www.diyaudio.com) and the Pass Forum and ask about building an Aleph 3 or Aleph 30 (50+50 watts). Alternatively check out www.Audiogon.com (http://www.Audiogon.com)

Ian.
Thanks for your very informative and concise explanation. From what I have heard from my newly acquired 4343's, your assessment is spot on. They are great with jazz but can be harsh on rock, vocals an so forth. Your recommendations on driver replacement is also the same as what I have decided on from studying the other postings here as well as some of your earlier ones. The crossover is my only real concern at this point.

Regards
Robert

Ian Mackenzie
08-17-2020, 01:23 PM
There seems to be a need for guidance and technical advise on all manner of things associated with these systems. A lot of information is now buried, fragmented or dated as time marches on.

To that end l want to put it out there l am available for few hours a week in these uncertain times to work through any specific requests for assistance. I thought it might be interesting to try face to face conversations via Zoom or one of the other systems or What’s App. Too much is lost in an email or a post.

So, if you see this post and wish to figure something out send me a pm.