This may be heresy...

[Soloford]

I have a set of 4343B's...done some work on them before I found this forum (foam replacement, diaphragm replacement).

I noticed that after turning the face on one of the speakers 90 degrees (see the pictures on the 2405 diaphragm replacement thread) and turning the speaker on its side, the sound is more....coherent? Not sure of the term, but it sounds better than before when it was upright.

I live in a pretty small place and in an effort to have more space, I mounted the left speaker on a shelf a little above head height when sitting. The right speaker is still upright, mounted on a shelf about two feet off the floor.

After turning the upper baffle 90 degrees, all the speaker components are more tightly spaced.

The left speaker is currently 41 inches wide, so to speak. I'm considering cutting it down to 36 inches...eliminating about five inches that used to be at the top (now on the right). This new cabinet size would then be 36 inches wide by 25 inches high and 15 inches deep.This would still give me a margin of about an inch between the mid-range driver on the right side of the speaker cabinet...similar to the one inch space between the woofer and the left side of the cabinet.

I have been told that this would affect the bass response.

Needless to say, I have many unresolved questions regarding this possible action....not the least of which is the fact that it's irreversible. I would be doing it for both speakers.

I'm asking for technical feedback relative to how this would change the sound, and how to mitigate those changes.

Looking forward to your responses (with some trepidation).

[Mr. Widget]

Needless to say, I have many unresolved questions regarding this possible action....not the least of which is the fact that it's irreversible. I would be doing it for both speakers.

Build new cabinets that do exactly what you want... I personally have never liked the fact that the 4343 was so shallow. I'd much prefer to see (hear) it so that the baffle was taller and narrower, but do what ever works for your application.

If you don't have the woodworking skills... there are several talented woodworking members in the Pacific Northwest. If you are interested in getting some help, you might do a search or three of DIY projects... you will find a few folks in your corner of the world.


Widget

[Soloford]

Hi Mr. Widget - when you say "build new cabinets"...you're talking new cabinets, right? Not cutting down the old ones? But then that still doesn't solve the issue of the box resonance....

I'm thinking that cutting down the old ones would be much easier than building totally new. I'm OK building either way...just seems like more work to go new.

Building new would present an additional problem...What to do with the old cabinets? They do take up space. I had quite a juggling act just pulling the face baffles out to re-diaphragm the 2205's! Did I mention that this is a very small space?

Speaking of the Pacific Northwest and Seattle in particular...any ideas as to whom to take the 2231H's for re-coning? I have the JBL 2235 re-cone kits already. When I needed to have the re-foaming...Speakerlab (a local shop) said they wanted $500 each pair of drivers...and needed to hold the speakers for 3 or 4 months (!) to work into their schedule. Not gonna happen!

I wouldn't want to be without them for over a day.

And I'd want to watch the work being done........

Is there anyone in Seattle that builds new networks? From what I've read in the forums, that would be the simplist thing to do for increasing clarity. Actually, I was thinking of building the new networks myself. After all, you guys already figured out the specs...and it's just a matter of buying the parts and soldering them together, isn't it? And I already have a soldering iron....

But to which spec to build new networks...4343B or 4344?

My plans for the 4343B's aren't that complicated...re-finish the cabinets to make them a little prettier, re-do the woofers to 2235's, add a separate amp to drive the 4343B's with...still using the pre-amp part of the home theater setup using the Denon 1908...and maybe updating the network components.

Replacing the diaphragms didn't produce much of an improvement, which to me indicates that they haven't been abused too much. Which is good news. I'm thinking that since the sound quality via the networks is mostly the result of a chemical process...and time is the enemy there...not abuse. So it's probably a safe bet that there would be noticeable improvement with fresh parts. Yes? No?

Cause I really, really like the way they sound already!

A big part of this effort involves building shelves for both the JBL's...hence wanting to reduce the size a bit.

So far, the best improvements in sound have come from the new foams (even tho I put them on the wrong side of the drivers), and surprisingly enough...turning the left speaker on its side. I wasn't expecting that. I've been living with it now for some months...and I really like it.

Down the road I may consider bi-amping...I'm looking to pick up both amps now. I'll need one anyway for driving the fronts with, and I think I know how to do that with the 1908. Not exactly sure... But am more than a little worried about the external crossover. Especially without a lot of help.

Before bi-amping, I want to maybe pick up a pair of 4412's or maybe L166's (I like the retro look...but not wild about parts replacement) as the side speakers in the HT setup. Move the little Ushers into the kitchen.

I've discovered, with this project, True Happiness!

Anyway, thanks for listening.

[scott fitlin]

$500 to REFOAM a pair of woofers, and HOLD them for 3-4 months? That is PURE BULLSHIT! I know hourly wages have gone up, but, not this high! NOOOOOO!

RUN, do NOT WALK, to a more reputable service center. I wish I could point you in a direction of a competent reconer in area area, but I'm sure someone here will have the info you need.

[Mr. Widget]

$500 to REFOAM a pair of woofers....

That must have been for reconing the pair... which would be about right.

As for what to do with the old cabinets? You can't store them somplace?

The 4343s are worth $2500+ depending on condition. The drivers are not. If you cut into the cabinets they become worthless... you then only have a collection of raw drivers.

As for cabinet resonance? I am not getting this, what resonance are you talking about? A new cabinet could be better built and proportioned than the originals. What resonance are you concerned about?


Widget

[lansingfan]

That must have been for reconing the pair... which would be about right.

As for what to do with the old cabinets? You can't store them somplace?

The 4343s are worth $2500+ depending on condition. The drivers are not. If you cut into the cabinets they become worthless... you then only have a collection of raw drivers.

As for cabinet resonance? I am not getting this, what resonance are you talking about? A new cabinet could be better built and proportioned than the originals. What resonance are you concerned about?


Widget

a smaller speaker that you could enjoy without hacking up the 4343's. It sounds like they are in the wrong environment. Maybe a 10-12" based speaker with sub reinforcement.

[Soloford]

Mr. Widget - My discussion with Speakerlab was via telephone...I specifically asked them about re-foaming the drivers in the 4343B'S. I don't believe that they were answering based on re-coning. As you no doubt know, my 2231H's and 2121H's can't be re-coned to original specs...they must be re-coned as 2235's and 2122's of which no mention was made. In fact, I had never even heard of the specific driver numbers until I started reading this blog. I was discussing re-foaming the two drivers in the 4343B's...But who knows...miscommunication happens.

As I mentioned...I have no place to store the old cabinets. I have 500 square feet of space. Period. As the mad hatter exclaimed..."No Room!"

I don't think I would argue either way about the residual value...since I have no intention of selling them. I just want to make them sound better, and maybe make them a little easier to live with.


As for the resonance issue...I had earlier PM'ed one of the senior members here asking "My question is this...Would the shortened cabinet size affect the over-all sound of the speaker?" The reply I got was "It will effect the bass response". Perhaps I misspoke in representing the changed bass response as a resonance issue. I had thought that since I wasn't talking about changing the configuration of the part of the cabinet surrounding the woofer, perhaps the indicated change in bass response would/could be due to the overall change in cabinet dimension. As in my previous comment...miscommunication is possible.


lansingfan - thank you for your comment as to replacing the 4343B's with a 10-12" based speaker with sub reinforcement.

I'm not interested in doing that. I already have a powered 18 inch sub as part of my HT system. And I am in fact looking for - as I mentioned when I started this - either a pair of L166's or 4412's to replace my side channel speakers.

I really like the 4343B's as the front channels. I've carted these things all over the world with me (London, Paris, Sydney and Auckland) and I have no intention of ever parting with them.

But then...never say never.

[herki the cat]

=...So far, the best improvements in sound have come from the new foams (even tho I put them on the wrong side of the drivers), surprisingly, I really like it. Anyway, thanks for listening.

Humm... If the foam is installed on the wrong side of the cone edge, you might want to examine the voice coil/spider for inadvertent displacement from a neutral position. The spider should be dead flat, which normally results with the foam edge on the correct side of the cone.

Good luck, herki the cat

[Soloford]

So Herki Cat (Brings back memories of Elton when I was in college)...are you suggesting that I re-foam the mid's...to put the foam on the back? I could do that.

I'm looking for someone here in Seattle to re-cone the 15's with the JBL 2235 kit I have...but no luck in getting a name so far.

And the forum doesn't offer any help at all in doing it myself.

[Soloford]

Does it really make a difference? As to where the new foams are mounted?

I just watched a pair of beat-up 4343's sell on ebay for $2850...the write up to them was as follows...

Here we have a beautiful pair of JBL 4343 Studio Monitors. They have been pampered their entire life and used with a Mcintosh system. All four of the Woofers were refoamed by Speaker City in Burbank California. They are a leading repair shop and only do first class work. They have been tested and work as new. These weight in around 175 lbs each and are vaneered in hand selected Walnut. One end of each speaker is in rough shape from sitting on the floor and being moved around. The rest of the cabinets are in very good shape only showing a few compression marks. One speaker has a faint ring from a glass and some paint transfer but no damage. Trying to describe these speakers in detail makes them sound like they are in bad shape, THEY ARE NOT! These show quit well with all corners and edges in excellent condition. The grills are a dark Navy Blue and are also in excellent shape. The 12 pictures I am allowed here show mostly the bad stuff. Please email me for more pictures of the speakers, serial numbers (which are consecutive), internal workings including the cross overs, cabinets etc., They are listed without Reserve at a very reasonable starting price.

I captured a couple of pictures of them as well which I could post if anybody wants to see them. Both the mids and low drivers had new foams attached...on the front.


Similarly, I followed a pair of L166's on ebay...they sold for $500 plus $100 for shipping...they had just been completely re-furbished (and looked really pristine)...and guess what...the new foams on them had also been attached to the front.


Both these re-foams had been done by supposedly professional shops. I looked at the 4343's with a very jaundiced eye, since they were so at odds with the write-up. I came close on the L166's cause they looked so good. Too good, I guess.


So does it make a difference? In sound? or in longevity of the driver affected?


I'd really like to get a technical answer on this...as to whether it matters on 30 year old drivers. Really. And this is probably the best place in the world to get an answer to that question.


Also saw a pair of L200 empty cabinets...not in too bad condition...asking $400. Cause the owner had parted them out...the horn, the driver, the crossovers and the l-pads.


I figure it would cost at least $400 to build a new pair of L200 cabinets.

[herki the cat]

So Herki Cat (Brings back memories of Elton when I was in college)...are you suggesting that I re-foam the mid's...to put the foam on the back? I could do that.

Move the foam to the back? absolutely not. That will destroy your expensive foam. , You said you were happy with the sound. Save the input for your next refoam job. If you have any compromise with cone excursion it will happen below 40 or 50 Hz and you may wish to use a high pass filter to cut the 20 to 30 Hz response a little, and especially the rumble spectrum below 20 Hz all the way down to 2 or 3 Hz..

Reproducing the pedal notes of the pipe organ in the 20 t0 30 Hz spectrum is another world requiring multiple 18 inch drivers and several hundred watts of power, and that requires sophisticated rumble filters. It wont happen with 15 inch drivers without horns as big as your living room. What you have is probably OK for now.

cheers, herki the cat

[Soloford]

Wow! Two things just happened. I just picked up a B&K EX-442 power amp. Now I can drive the 4343B's using the Denon pre and the B&K (200 watts). Not exactly bi-amped...but should be an interesting turn considering the attack characteristics of the B&K.

The second thing...finally found the JBL authorized repair here in Seattle. I may be able to get them to re-cone my 2231H's with the JBL
kit. Since the 4343B's aren't on their list of pro gear...(too old probably)...they may not be able to do it. But they can still get the parts. Here's hoping...!

If in fact they can do the work, I'll go ahead and have them re-coned to 2234's rather than the 2235's. I'm hoping that gets a sharper attack...not looking for deeper Hz's.

I'll keep the mass ring...may some day go ahead with bi-amping...but its a long shot. I've lived thru the hell of getting hum and buzz out of my system years ago...not going there again! Silence is golden.

And the repair guy here agrees with you Herki...once the foams on the front...leave it! No problem with the life of the driver. Done and done.

So I may have a pair of JBL re-cone kits (C8R2235) available for sale real soon, since if the shop will do the work, I won't need them. Wonder if anybody here could use them? They are pricey...$214 plus shipping per. If so, PM me.

Now to go review the crossover rebuild threads. I just may tackle this myself.

The wife agrees with most of you...thinks cutting off 5 inches of cabinets is just crazy. But I'm thinking...what's to lose..?!!! As brother Ray says..."Booorrn to lose........"

Good company. Having fun.


And speakerdave...enjoyed your flame, dude. The amethyst...yeah, picked that up when I was working in Rio back in....well, before it became a battle zone.

[Soloford]

Yup. Am going ahead with the re-cone here. So my JBL re-cone kits are available. The kits are currently going for $214 per. Did some checking...I paid $179 per when I bought them.

Anybody interested?

[herki the cat]

Wow! The wife agrees with most of you...thinks cutting off 5 inches of cabinets is just crazy. But I'm thinking...what's to lose, Good company. Having fun.

Your wife is absolutely right, the original JBL cabinet system is very valuable.
Ian Mackenzie has posted design details of a very well damped cabinet..

cheers herki the cat

[Soloford]

Herki - I have no doubt that the cabinet design that Ian came up with is superior to the vintage box. Unfortunately, I have no space in which to build a new cabinet. My work area is an outdoor deck.

I mean no disrespect with this thread to any of the folks that love the look of the old 4343's. It's just that I've found that the speaker (with the upper baffle turned 90 degrees) sounds much better on its side than when the speaker was upright. I find that I get a much bigger "good" sound area.

I have a sneaking hunch that the 4343 should have been sold as a side mounted speaker from the get-go. But that's just my opinion...and is not meant as any kind of criticism for the original designers of the speaker.

After living with the speaker on its side for about 6 months....I think they would be much easier to live with if they were only 36 inches wide instead of the normal 41 inches. That's not much more than a three-way mounted sideways.

And I think I can do a really good job of reducing the size. It certainly won't be a half-a$$ hack job.

There are a couple of practical things that I want to change on the cabinet anyway...first is to make each driver removable individually from the front.

As they are now,,,for removing either the 2420 or the 2405 I have to take the entire upper baffle off. What a pain! Just look at all the specialized stands that I had to build when I did the 2420 diaphragm replacement thing!

And the other big thing I want to do is move the network to outside the cabinet...to the back. I look at the custom network that Mr. Widget built for that Japanese gentleman a couple years ago...I only wish I had skill to do something like that! What a work of art! I've tried to contact a couple of senior members here to just buy new crossovers...but I take it no one has started marketing them. And in truth...I'm not sure what I want yet anyway. What to do about the bi-amp switch? Which drivers to build it around.

Like I mentioned earlier...I'm looking to upgrade the 2231's to 2234's. I want to get as much detail as possible...especially at moderate volume...and from reading extensively here on this forum, it seems like the biggest returns are going to be in the woofer upgrade, adding more power to the equation, and the network.

Since I figure that my own efforts to update the network are going to have many iterations (mistakes)...it needs to be accessible easily.

And maybe the L-pads need to be moved to be part of the new externally-mounted crossover box.

So maybe I'm taking a chance on making the cabinets un-saleable. They're unsaleable now...in the sense that I have no intention of ever parting with them.

I see this as an opportunity to turn the cabinets into works of art...as well as making the speaker more practical to maintain while improving on the sound.

This thread started as a result of me asking one of the very senior members (that I have a lot of respect for) giving me some suspect advice...that by modifying the size of the cabinet that I would be changing the bass characteristics. I don't understand how that's possible, unless by changing the size of the cabinet somehow changes it's natural resonance which in turn could have an effect on it's bass characteristic.

Unfortunately, I think its entirely possible that I got some bad advice based on some implied disapproval of the nature of the project.

But the good news is that there is a shit-load of information here on this site...and I'm very fortunate for having found it. The difficult thing is deciding what works for me versus what others are trying for.

Anyway Herki, thanks for the helpful advice. Appreciate your technical savvy!