Treble drivers in 4345

[speakerdave]

On another thread I mentioned that I was listening to my 2450's with SL diaphragms, and Z-man asked:

May we know the details, David, when you have a chance? Two or three-way? Horn? Other drivers?
So here goes:

I have them on 2311's in my 4345's. Ya, they fit. They are almost an inch smaller than the 2441 (which I believe was tried by Bo), and the fattest part is just aft of the dog box for the 2122.

Both the diaphragms were new, and I believe there was a break-in period, though a rather steep one. They don't seem to be changing much now after about twenty or thirty hours of listening.

I plan to go back to the original 2421's when my new diaphragms get here. I've been experimenting while waiting. The old diaphragms in the original drivers were exhibiting some of the characteristics of fatigued aluminum.

I like the aquaplas coated titanium 4" driver. Of course there are a couple of aspects of what I'm doing that make any conclusions difficult, to say the least. 1) I'm plugging and playing with the stock networks. With the current substitution that probably means that the frequency balance of this portion of the frequency range has been shifted downward a bit. 2) the 2311 horn may be acoustically different from the 2307. Taking those unknowns into consideration, I'll say that I like the sound of this combination. It's not as warm as I like, but it is listenable at high volume, which I cannot say for all compression drivers and horns I've heard.

I've also experimented with a pair of refurbed TAD 2001's on 2307's. Those I like very much, although they do not seem to respond well to high levels. (Widget says the diaphragms may not be seated correctly). At lower volume they are quite marvelous. That aside, I'll say that beryllium seems to be the bee's knees. It is the only driver I've listened to that did not make it difficult to balance the imaging and harshness. That is to say, with other CD/horn setups I've always had to work with the levels to find a compromise between tizz and hash on the one hand and letting the imaging recede into the speakers on the other. I'm guessing that with these drivers on the stock network the frequency balance would be shifted upward slightly. The detail and lifelikeness with beryllium comes through nonetheless.

I never heard anything objectionable with the 2420's in my 4333A's, and I'm hoping the same will be true with the new diaphragms in my 2421's. I am aware that some people prefer the 2420 to the 2421, though. Anyway, we'll see.

I believe some of the Australian members with 43XX monitors are using 2425's with titanium diaphragms and find them to be good. I may have a go at that before I revert to standard form.

David

[Ian Mackenzie]

David,

Your post sums up my findings.

Its a careful balancing act with these 4 ways. You can expect to spend weeks not days setting them up properly. The better controlled diaphragms are easier to balance. I heard some Tad 2001 when in the States and they are impressive but $$. The titanium is warmer than the aluminium, aquaplas make them sound more mellow and refined and lowers the sensitivity by about -1 db so you can compensate by adjusting the L pads.

If you intend to use better diaphagrams the stock networks warrant improvement with more current day soa parts. Pm me for details on how to go about that.

[speakerdave]

It could be interesting to see someone come up with a 1.5" version of the old fog horn to retrofit into the 4344/4345 and maybe even 4355. I think subwoof had a pair but I'm not sure how that turned out.

Ya. He called it the 2313. He never reported on a listening test as far as I know. My personal hunch is that with a throatless driver like the 2435/435Be that horn would be too short. I think it should have been made from a 2312 instead of a 2307. I'd try it myself, but I don't have the shop facilities. On the other hand, that $210 Japanese 1.5" to 2" adapter on the 2311 would probably work as well.

David

[Ian Mackenzie]

This is taking a wider berth on the topic but if you do a re hash it would be fun to see a Be driver mated to a better horn like one of Jack's horns or something. The depth of the 2307 and the resulting offset causes some power response issues around 1300 crossover point in the vertical plane. The sweet spot is usually a one seat affair making it a pretty selfish experience. I am sure it would image better too with something else, a bat slayer on top would also be really cool if one were to really tart it up.

That means a whole rethink but if someone has the resources to trial some waveguides and other stuff the outcome may prove productive.

[Ian Mackenzie]

Thanks Rob

Could be interesting, I will try and find Zilchmeisters data.

Again this is drifting OT but with all the current information Jack as presented recently if we are talking Hifi I think we are talking about a different bird of prey. I think one of the guys has a diy version of this in train at the moment

Otherwise someone may as well DEQX the stock setup and be done with it but frankly the money would be better mortgaged on a Array System:applaud: .

[boputnam]

They are almost an inch smaller than the 2441 (which I believe was tried by Bo), and the fattest part is just aft of the dog box for the 2122.No, I balked. After taking and re-taking careful measurements, it was clear I'd need to mod the dog house - the motor was just too dang fat. Subwoof was anxious for me to give it a go, but I decided it wasn't the type of corrective surgery I felt was needed.

What I did do was put new diaphragms into the 2421B's and have been real happy with that.

[Ian Mackenzie]

Yep,

I think your looking a plain better diaphragm or a better driver like the Tad 2001. There ain't much room in there.

Does anyone know what became of Guido's after market be stuff?

On a different note I am going to try an experiement next week with soft cell foam around the mouth of the 2307 and if I can a soft cell plug like the Geddes plug to see if it does anything better.

Ian

[Earl K]

It could be interesting to see someone come up with a 1.5" version of the old fog horn to retrofit into the 4344/4345 and maybe even 4355. I think subwoof had a pair but I'm not sure how that turned out.

- 6 Months ago I acquired a bunch of 2431H drivers ( as part of a refurb project for my SR business )
- As a laff, I created a 2313 out of a 2311 and a Selenium 1.4" to 2" adapter .
- I achieved my ( bench project ) goal of creating flat response from 1K to 10K ( this was July I think ). I could actually entertain an 800 hz crossover point.
- If I remember correctly, I did construct ( and use ) either a two pole ( or maybe 3 pole ) bump filter . I coupled the DI index of the horn / with say the 2.5 db per octave "lift", available from creating a frequency dependant LPad ( buried coil ) . The overall lift was moderated ( and flattened ) by a lowpass coil ( cutting in at a lowish value ) . Anyone who has studied the N9800 will understand what I was up to and why.
- It was a bench study only (so no records were kept ).
- I'll also assume a series LCR notch filter was necessary to make it all really smooth / since I can't remember building much in the last couple of years that couldn't benefit from even a tiny one . :p

- If I had a 434x type box , I'd be going this route in a heartbeat ( the better the compression driver / the more I want to hear it / somewhat like the expanded duties in the 4348 ).
- The 435Al prices ( if and when available, represent great value ) . I'll assume the 435Be prices that you can get also represent great value.
- I haven't heard any Be products from JBL , so I don't know what I'm missing .


:)

[Earl K]

The Al is bearable once you aquaplas it as JBL did with the 435Al-1.

Oh,,, for some reason I thought ( assumed ) all 435AL variants were aquaplased . I guess not .


:)

[Earl K]

I should say that "bearable" is a subjective term. I personally have a low tolerance for any kind of compression driver / horn anomalies. The usual suspects really wear on me after awhile, more so for CD music than DVD movie playback.

-hmmm,,, well my tolerance of all these sort of anomalies did lead me to give up on the use of JBL drivers for the home environment ( 2.5 years ago now ) / while at the same time finding that what I was after, came from big Altecs' ( I wouldn't have thought that a few years back ).
- Obviously given the testamonials for the new 475Be . I would be keen to accept a pair for my 55th birthday . :p

:)

[speakerdave]

It's been posited that the driver is operating as a direct radiator on 2311, in some part. Seems the length would also partially mitigate time alignment issues. . . . .

. . . . at 500 Hz, yes. A deep throated driver like the 2450 should still be loaded at 1.3K, using the half-wavelength standard.

David

[Ian Mackenzie]

While we are talking about the horns and system in general I would like to mention that I have successfully modified a stock factory 3145 network with minimal invasive surgery. We identified a number of issues that have been addressed.

Playing the modified stock networks for the first time this afternoon they literally blow the stock networks out of the "water".The system is biamped with the JBL DX1.

Better diaphragms would (are) be nice and the icing on the cake but the system delivers an otherwise stellar performance with the modifications.

I will post some details later in the week.

Ian

[4313B]

I was under the impression that speakerdave was talking about his 4345's. I thought he had purchased a stock pair. My mistake. I have removed all my posts.

[Ian Mackenzie]

Rob,

I agree, there are a number of diyers who are interested in advanced technical solutions and there are an equal number of members with stock systems who may like them refreshed. We've all been over this numerous times but it would be interesting to see a V3 equivalent network. Its horses for courses with all this stuff.

I decided to look inside the stock 3145 network because I was asked to by a member and I was interested in doing some measurements, a subject evaluation, identifying areas for improvement and exploring the potential for upgrading it. I am not aware if any previous thorough "physical" examination of a stock 3145 network pulled from a vintage system. More on this another time.

[Ian Mackenzie]

I am also finding it also hard to remember who has what, there are so many things a happening on the forums these days.:)

[speakerdave]

I am also finding it also hard to remember who has what, there are so many things a happening on the forums these days.:)

Indeed, and it is especially confusing when the threads become garbled.

Like Giskard, I was wondering why this thread was needed for yet another discussion about the PT wave guides. I was specifically addressing the options for treble drivers in the classic factory 434X monitors.

David

[Ian Mackenzie]

Hi Dave ,

Yes I understand.

I think you will like what you hear when the new diaphragms are installed.

I would suggest that what you end up hearing is often the integration of your whole system, not just the diaphragms or the drivers or the horns.

Just how well it all works is often as case of attention to detail setting up. This is why I take comments about specifics with a gain of salt unless I relate it to my own rig if you known what I mean.

Can you post us another pic of your speakers please.:bouncy:

Ian

[speakerdave]

I just thought there might be some others who would be interested in hearing about my messing around with different drivers that will fit into these enclosures. Probably some of what I'm hearing that I would like to improve is coming from the crossovers, so that should be the next step for me after installing the new 16R2421's. I generally do prefer to listen to vintage speakers in the stock form made as good as it can be, but I had these drivers around for other projects and thought I'd see what happened.

I guess I thought my parameters were understood, but I should have articulated them clearly myself. It is certainly one advantage of building a speaker similar to one of the classic monitors, that if you want to cut a larger hole in the baffle there is no reason not to. I just couldn't consider hacking a 4345, and I don't really want a horn sitting on top of it either, so the discussion about alterations that would have involved either of these or a new box didn't seem relevant to me. I can see how someone else might find it interesting and valuable, though.

David

[Mr. Widget]

I just couldn't consider hacking a 4345...I wouldn't think so... but it is suprising what some people will do.


Widget

[Zilch]

I just thought there might be some others who would be interested in hearing about my messing around with different drivers that will fit into these enclosures. Probably some of what I'm hearing that I would like to improve is coming from the crossovers, so that should be the next step for me after installing the new 16R2421's.It sounds like the SL diaphragms worked out fairly well for you.

I, too, will be interested to hear how you find the other horns and diaphragms compare.

The 1.5 to 2" throat adapter with Be 2435HPL on 2311 sounds like it'd be workable, as well, if the impedance mismatch could be overcome. :dont-know

[subwoof]

As it turned out, the distance from the coil to the horn exit was the shortest of the (3) combinations so it might have some issues at the lowest frequencies in that band BUT it sure had better dynamics and lower distortion than any other combo.

And the large format titaniums can be slammed without much worry compared to the $maller and fragile aluminum$.

I made the "2313" from a pair of beater H91 ( 2307 ) and if I remember correctly, the length would of been the same if I cut down a pair of 2312's since I simply measured from the mounting flange to the point where the I.D. was 1.5"

The 2311 / 2330 combo wasn't a direct fit since that adapter was for the altec 1.4" driver and the flange was too small for the larger of the (2) 1.5" mounting diameters.

I sold the 4345's before I was able to do much listening and my current projects use the 2332 ( array 90 degree ) so they now sit in the storage room.

If some enterprising member wants to borrow them for a listening / measurement test, let me know. I'm pretty sure the flanges are drilled for both of the 1.5" mounting diameters.

sub




Quote:
Originally Posted by Giskard http://audioheritage.csdco.com/vbulletin/images/buttons/viewpost.gif (http://audioheritage.csdco.com/vbulletin/showthread.php?p=133524#post133524)
It could be interesting to see someone come up with a 1.5" version of the old fog horn to retrofit into the 4344/4345 and maybe even 4355. I think subwoof had a pair but I'm not sure how that turned out.

Ya. He called it the 2313. He never reported on a listening test as far as I know. My personal hunch is that with a throatless driver like the 2435/435Be that horn would be too short. I think it should have been made from a 2312 instead of a 2307. I'd try it myself, but I don't have the shop facilities. On the other hand, that $210 Japanese 1.5" to 2" adapter on the 2311 would probably work as well.

[4313B]

If some enterprising member wants to borrow them for a listening / measurement test, let me know. I'm pretty sure the flanges are drilled for both of the 1.5" mounting diameters.Sure. I'll try them out since I'm working on 4344's, 4345's, and 4355's right now anyway. Thanks!

[speakerdave]

I made the "2313" from a pair of beater H91 ( 2307 ) and if I remember correctly, the length would of been the same if I cut down a pair of 2312's since I simply measured from the mounting flange to the point where the I.D. was 1.5"

I'm puzzled by this because the 2312 goes from the same throat size to the same mouth opening over a longer distance. It must have a more gradual expansion. Anyway, I'm not advocating cutting up 2312's, which are less common. I think the thing to hack would be a pair of 2327's and bolt them to 2311's. If I run across a pair of beaters, I will have a run at it.

David

[speakerdave]

It sounds like the SL diaphragms worked out fairly well for you.
Ya, they are sounding pretty OK. Like the beryllium, there is a range of acceptable level settings.


The 1.5 to 2" throat adapter with Be 2435HPL on 2311 sounds like it'd be workable, as well, if the impedance mismatch could be overcome. :dont-know

Oh, yes. Thanks for the reminder.

David

[Chas]

I just thought there might be some others who would be interested in hearing about my messing around with different drivers that will fit into these enclosures. Probably some of what I'm hearing that I would like to improve is coming from the crossovers, so that should be the next step for me after installing the new 16R2421's. I generally do prefer to listen to vintage speakers in the stock form made as good as it can be, but I had these drivers around for other projects and thought I'd see what happened.

David

David, as a 4345 owner, I would be very interested, though I must admit that I'm somewhat confused reading through all the posts.

For now, here is what I can understand:

1. A 2440/1 with a 2311 won't fit, due to the driver diameter encroaching on the dog box.
2. A method to mount a 1.5" driver to the opening in the baffle board is needed. Correct? Possible course of action is to somehow use a 2327 adaptor? How could this work?
3. As a point of reference, are your 4345's upgraded with new crossover capacitors? I hear what you are saying about retaining vintage parts but from what I have experienced, the old JBL OEM caps are "covering up" a lot of information, if they are still in use...

Charles.

PS I would sure be interested to know what Giskard is up to....

[mikebake]

PS I would sure be interested to know what Giskard is up to....

I think he is getting into Nascar now............

[4313B]

I would sure be interested to know what Giskard is up to....Project May

Custom 1200 Array Project using Be components

Custom K2-S5800 Project using Be components

Replacement of JBL 4406 5.2 mini surround sound system with Tannoy Dual Concentrics.

Three pairs of 4345's. (Still working on the final equivalent bandpass filter for the 2421/2425. Bi-amp only filter has been corrected for the 2122. The 2405 portion is complete.)

Four pairs of 4355's. (The final version of the stock equivalent network design is done as of this morning).

[4313B]

I think he is getting into Nascar now............That was yesterday dude. ;)

[Ian Mackenzie]

David, as a 4345 owner, I would be very interested, though I must admit that I'm somewhat confused reading through all the posts.

For now, here is what I can understand:

1. A 2440/1 with a 2311 won't fit, due to the driver diameter encroaching on the dog box.
2. A method to mount a 1.5" driver to the opening in the baffle board is needed. Correct? Possible course of action is to somehow use a 2327 adaptor? How could this work?
3. As a point of reference, are your 4345's upgraded with new crossover capacitors? I hear what you are saying about retaining vintage parts but from what I have experienced, the old JBL OEM caps are "covering up" a lot of information, if they are still in use...

Charles.
....

Hi Chas,

In short from my point of view its a whole system thing when it come a stock vintage setup or an upgrade, either way it must be balanced.

ie If you have vintage amps, vintage source etc stay with the stock crossovers and they will serve you well. If you think you want to ramp up to current day mass market, do so with you amps, source and crossover parts. If you want the best, go for the best in each area. If someone promises you the world with one update alone, they are pulling your chain(wankers!).

In reference to the stock crossovers, the improvements that can be made to them in total are quite revealing to the trained ear and go beyond the "those capacitors". To do that you need a baseline and need know what to look for and have a pair to pull apart and examine.

Unfortunately what some people think is better is in fact truely horrible but life goes on so trust your own ears.

You also need to have several levels of source, amps and parts from mass market all the way up the very best to be able to work all this out. The fact is there are few things that qualify as the very best. HK is not one of them but is the better end of mass market and suits most consumers needs well.

Back to those stock crossovers. I counted not less than (007) seven specific improvements to the stock crossovers that made in total a significant audible improvement to the subjective experience. Yet they remain true to their original form.

The total system that the improved stock crossovers will be used in is approaching a hi end audio system.

No snake oil, no false promises or marketing ploys. Mostly attention to detail and common sense. But most of all being thorough.

If a jobs worth doing, its worth do it well.

The transformation was a revelation!

In a short while the details will be published.

Ian

[Chas]

Project May

Custom 1200 Array Project using Be components

Custom K2-S5800 Project using Be components

Replacement of JBL 4406 5.2 mini surround sound system with Tannoy Dual Concentrics.

Three pairs of 4345's. (Still working on the final equivalent bandpass filter for the 2421/2425. Bi-amp only filter has been corrected for the 2122. The 2405 portion is complete.)

Four pairs of 4355's. (The final version of the stock equivalent network design is done as of this morning).

WOW!:)

Re. the 4345's: When you refer to the corrected biamp filter for the 2122, will this address GT's comment about the FR at 290 Hz?

[Chas]

Great stuff, thanks Giskard. I'll look at your posts and graphs a lot closer when I get home. I think I may have misunderstood GT when he mentioned that neither the 2245 nor the 2122 is flat at crossover when biamping.

Charles.

[speakerdave]

1. A 2440/1 with a 2311 won't fit, due to the driver diameter encroaching on the dog box.
Right. The smaller 2450 just makes it.



2. A method to mount a 1.5" driver to the opening in the baffle board is needed. Correct? Possible course of action is to somehow use a 2327 adaptor? How could this work?

If you remember subwoof's thread about cutting down the 2307's. I was thinking that cutting down 2327's might make a difference on the length, but measurements would need to be made of the cutdown 2327 plus 2311.

I would also be curious about the possibility of turning a custom tractrix/rams horns type horn for the 2435/435Be that could be mounted in the existing hole from the front and held in place by screws coming from the inside through the existing bolt holes. That would be clean and might be short enough to have adequate dispersion over the pass band.



3. As a point of reference, are your 4345's upgraded with new crossover capacitors? I hear what you are saying about retaining vintage parts but from what I have experienced, the old JBL OEM caps are "covering up" a lot of information, if they are still in use...

I'm still using the stock crossovers. I will not be modifying the stock crossovers or removing them, but rather making entirely new ones for biamping and mounting them on the outside of replacement access panels for easy fiddling.

David

[X_X]

Hello all,

I am about 75% complete with my 4345 project and before building crossovers I wished to biamp. I did not know how I was going to work out the issues...

I purchased an electronic crossover board (http://www.marchandelec.com/xm1.html) from a company called Marchand set at a point of 400Hz; It is both high pass and low pass. This should work fine, yes? I was hoping that its use would eliminate the need for me to passively attenuate anything between the 2245/2122. The Fs of the 2122H is out of range and the slope is rather steep on this crossover unit (@28db/oct LR). I should be able to (essentially) eliminate those portions of the crossover schematic and build the rest to spec- correct?


Obviously, I need air cores and I'd like to eliminate the Lpads as Greg Timbers suggested in another thread. The more I want to "simplify"- the more difficult it becomes! Has anyone built a purely contemporary high performance version of the 3145? Other than the excellent information found here in this thread- Is there a "revised" version of the 3145 posted anywhere?

Thank you in advance.

Nate.

[speakerdave]

Neither the 3145 nor 3155 schematics will be posted until they pay for themselves. It's been a free ride since day one here. In this particular instance I absolutely have to recoup time and materials. I hope this is understandable.

This is a great step forward, which I applaud unreservedly.

David

[X_X]

Neither the 3145 nor 3155 schematics will be posted until they pay for themselves. It's been a free ride since day one here. In this particular instance I absolutely have to recoup time and materials. I hope this is understandable.


I understand. This crossover work is very frustrating. I apologize- I did not mean to offend. I am not looking for a free ride. I had resigned myself to building the 3145 as-is. I just thought if a more premium version existed somewhere- I would use that.


Nice work, Giskard. I wish I understood it the way you do.


Nate.

[Chas]

If you remember subwoof's thread about cutting down the 2307's. I was thinking that cutting down 2327's might make a difference on the length, but measurements would need to be made of the cutdown 2327 plus 2311.

David

Yes, it was a really slick deal. Way outside my meager capabilities.

[X_X]

No offense taken at all. And no offense meant either. The "free ride" comment is merely one that has been mentioned by quite a few people.
I would like to get them posted by the end of the year. So far, given the level of interest, it looks like that will happen. My originally posted equivalent networks work just fine so long as you also use the L-Pads. I've posted those schematics in various places. How would you deal with the tapped autotransformers? They are not readily available.

Hi Giskard.

Autotransformers...I don't know where to find new ones; I haven't even looked. Short of winding my own (which I do not know how to do)- I'd be lost on that one. I did find your previous 'equivilent' networks and that is exactly what I had in mind when I said "3145". Thank you for that.

I hope your efforts are well rewarded. I know a lot of people must be waiting in a fever to see a quality reworking of the 3145 without all the guesswork and pitfalls that a casual tinkerer would invite. I myself am exited.

Nate.

[4313B]

Giskard is also discussing filters in another thead, an educational and insightful discussion for some and no doubt incomprehensible for others.Ian - I deleted all my posts and will consider addressing the number of members who have expressed their concerns in full in a new thread.

Great stuff, thanks Giskard. I'll look at your posts and graphs a lot closer when I get home. I think I may have misunderstood GT when he mentioned that neither the 2245 nor the 2122 is flat at crossover when biamping.I didn't fully cover the situation and will consider doing so in a new thread.

I just thought if a more premium version existed somewhere- I would use that.I'll post the final schematic in a few days.

[Fangio]

Ian - I deleted all my posts and will consider addressing the number of members who have expressed their concerns in full in a new thread.
I didn't fully cover the situation and will consider doing so in a new thread.
I'll post the final schematic in a few days.
:bouncy:

[mech986]

Hi Giskard.

Autotransformers...I don't know where to find new ones; I haven't even looked. Short of winding my own (which I do not know how to do)- I'd be lost on that one. I did find your previous 'equivilent' networks and that is exactly what I had in mind when I said "3145". Thank you for that.

I hope your efforts are well rewarded. I know a lot of people must be waiting in a fever to see a quality reworking of the 3145 without all the guesswork and pitfalls that a casual tinkerer would invite. I myself am exited.

Nate.

I don't know of anyone here in the states, but Malcom Jones of Falcon Componenets in Great Britain winds inductors and can wind Autotransformers or tapped inductors to spec. I'm sure there will be costs but if you have specific parameters and measured specs, he could do it. He works with iron core, ferrite core, iron dust, and air gap types. Shipping could be an issue but if there was a reasonable demand for a number of pieces, it could be worth a look.

Malcom was the first employee engineer at KEF when they started in the 60's. He designed and engineered the first Bextrene drivers, possibly in conjunction with the BBC. He worked on all the early KEF speakers up to the KEF R104aB and then went to his own company winding inductors and doing a lot of crossover work with KEF and others.

http://www.falcon-components.co.uk/

Regards,

Bart

[4313B]

That's cool but the point is to get rid of the tapped autotransformers. I feel you guys are forcing my hand because you won't drop it. I'm not real sure why. I have to think that it isn't all by design.

We've just upgraded to the lastest software that JBL uses and we are working with JBL on a few different projects of which May is only one. The plan was to not only do a final lock-in of the stock networks without using tapped autotransformers but to parallel development of completely new networks using the same methods as were used with Everest II. The purpose is to preserve the original voltage drives for those who wish to do so and to possibly offer a newer network option for those who wish to try that as well. It was even suggested that the single biggest improvement (again, for those with such an interest) might be to try a Be driver in place of the Al and Ti drivers so yet another network option was on the table for that.

Given the events of the last few days I'm leaning more towards just bagging the whole mess. I guess the question now is, who wants what to happen?

[X_X]

That's cool but the point is to get rid of the tapped autotransformers.

Definately!


It was even suggested that the single biggest improvement (again, for those with such an interest) might be to try a Be driver in place of the Al and Ti drivers so yet another network option was on the table for that.

Interesting.



Given the events of the last few days I'm leaning more towards just bagging the whole mess. I guess the question now is, who wants what to happen?

Count my vote for your continued effort, thank you.



Nate.

[speakerdave]

I guess the question now is, who wants what to happen?
You know me, Al, I see a heterogenous universe in which people respond to a variety of attractions and antipathies.

The 2450 with factory aquaplased titanium diaphragm is a real option. I am apparently in a seemingly asymptotic break in period and am still experiencing improvement in the sound. There is a bit of hardness yet in the sound of hard-blown sax, but I'm getting along very well with piano. Haven't really checked out chorus or acoustic guitar as yet (I'm not being systematic about this). I do know there are well-regarded ears which don't care much for the 2311. Nonetheless, I think this configuration will be a viable option for some because there is a market in used 2450's; the price point can be favorable. I have little experience comparing the JBL 2" and 1" drivers, but I think there may be something to the notion that the big ones just sound better. If you think it worthwhile, after I pull these you can borrow them.

Regarding the 1.5" drivers: I've done some measurements, and there is no difference in length between the 2327 plus 2311 and the 2307, so there would be no improvement in length over subwoof's 2313 if a 2327 were cut down instead of a 2307. Besides, the idea that the 2313 is too short is just a guess on my part; listening tests and measurements should be done. A number of people, myself included, are sitting on pairs of 2435's. The interest in them has flared up and died down a couple of times since they started showing up on eBay, and the problem is still the same--the horn. If someone with a lathe wants to try laying out a tractrix/ram's horns style of horn with a 1.5" throat, that will install in the 434x hole for the exponential "foghorns"--that could be the solution for that.

My new 2421B diaphragms are sitting here waiting to be installed. After I've done that I'll have a perspective on the stock configuration.

I still think beryllium offers the ultimate in fine detail. Buying used TAD drivers is probably too risky because of the cost of replacement diaphragms. Availability of new ones would have to be checked out. There 1" drivers work on the 2307, but the price of a new pair of TD-2001's or TD-2002's is not trivial, and I don't really see a lot of people going that way, nice as it is.

I think the next steps needed are: A network option for the 2450 aquaplased and a horn solution and network for the 1.5" berylliums.

It may be that Lansing Heritage Forums needs an R & D budget.

David

[4313B]

Great post dude!

[hjames]

That's cool but the point is to get rid of the tapped autotransformers. I feel you guys are forcing my hand because you won't drop it. I'm not real sure why. I have to think that it isn't all by design.

We've just upgraded to the lastest software that JBL uses and we are working with JBL on a few different projects of which May is only one. The plan was to not only do a final lock-in of the stock networks without using tapped autotransformers but to parallel development of completely new networks using the same methods as were used with Everest II. The purpose is to preserve the original voltage drives for those who wish to do so and to possibly offer a newer network option for those who wish to try that as well. It was even suggested that the single biggest improvement (again, for those with such an interest) might be to try a Be driver in place of the Al and Ti drivers so yet another network option was on the table for that.

Given the events of the last few days I'm leaning more towards just bagging the whole mess. I guess the question now is, who wants what to happen?

Okay - I'll bite ...
I'll admit I don't have the budget of some of the folks here (really wish I did), I build as best I can on a beer budget - but I do appreciate the taste of the occasional single malt.

That said - I'm quite interested in assembling a big box 4way monitor.
Room size is a constraint for me, so I'll have to do it with a 15 and the smaller box that it allows, rather than the nearly double size box needed for the 18s of the 4345s. For me - the 4343 sounds like a good compromise - or, as Ian mentioned - the 4344 Mkll type design (a bit more up-to-date) - but from what I've read in the forums of folks who've heard or own them, I want more the bottom of the American speakers rather than the Japanese sound.
What's needed to help move this forward in a fair manner - more $upport?
Maybe a member$ only side of the site to fund such design?
Don't be shy - If folks don't want to contribute they don't get access to such results, is that what's envisioned?
Boutique sound design?
Perhaps it ought to be its own website, apart from Lansing Heritage - keep Lansing Heritage an open and free exchange of ideas and put the pay stuff elsewhere to sink or swim on its own?

Really, what exactly are we talking about here - lets bring it out in the open, eh?

[johnaec]

What's needed to help move this forward in a fair manner - more $upport?
-------
Really, what exactly are we talking about here - lets bring it out in the open, eh?Heather - I initially wrote a long reply with my perspective on the situation, (while I don't have the electronics knowledge to design crossovers, I do design and build cabinets), but then decided it boils down to the fact that researching, designing, and testing things takes substantially more time that most people realize, and if you're doing it primarily for others' benefit, it's only fair to expect some kind of payback, otherwise, 'might as well just go fishin', or do a regular job that likely pays more in return...

If I'm doing a job that also includes the resulting "product" for me, then I'm definitely willing to absorb part of the expense, (as I think most others here do also). But I still like to think the rest gets spread around fairly, as I'm sure others do.

'Only speaking for myself here - others may have different ideas...

John

[Chas]

Heather, I haven't actually seen a 4344 or a 4343 in the flesh but as a 4345 owner, I think the smaller ones may in fact be slightly better with respect to cabinet panel rigidity. My '45's have very large side and back panels that are nowhere near as solid as my much smaller 4430's. They're well made and braced, but with panels as big as they are, it's difficult to maintain the same degree of inert properties.


Giskard, I would be very interested in any tidbits you choose to share here. Key words being you choose. Heck, If you just want to share the basics but keep certain proprietory information for paying clients, I wouldn't blame you a bit.

[4313B]

Room size is a constraint for me, so I'll have to do it with a 15 and the smaller box that it allows, rather than the nearly double size box needed for the 18s of the 4345s. For me - the 4343 sounds like a good compromise - or, as Ian mentioned - the 4344 Mkll type design (a bit more up-to-date) - but from what I've read in the forums of folks who've heard or own them, I want more the bottom of the American speakers rather than the Japanese sound.I think you may mean the 2235H/2122H-based 4344 as opposed to the 2231/2121-based 4343? It might also be cool to see someone do a 4 cu ft LE14H-x version. I consider the 4344 MkII out of scope as is the 4348. Those models are JBL Consumer and not JBL Professional Series and really aren't of the same genre to be fair.
'Only speaking for myself here - others may have different ideas...Nice post John. I deleted my first draft after reading yours. ;)
Giskard, I would be very interested in any tidbits you choose to share here.I'm kind of leaning towards a "forum project" wherein more than one or two people get stuck doing the R&D. I'm still pondering the ramifications of that.
If you think it worthwhile, after I pull these you can borrow them.If you think they are worth checking out then we should at least get an impedance curve and SPL/phase curve on them.
A number of people, myself included, are sitting on pairs of 2435's.Ok, maybe an impedance and SPL/phase curve on them as well.
If someone with a lathe wants to try laying out a tractrix/ram's horns style of horn with a 1.5" throat, that will install in the 434x hole for the exponential "foghorns"--that could be the solution for that.Anyone?
My new 2421B diaphragms are sitting here waiting to be installed. After I've done that I'll have a perspective on the stock configuration.Ok.
I still think beryllium offers the ultimate in fine detail.Ok.
I think the next steps needed are: A network option for the 2450 aquaplased and a horn solution and network for the 1.5" berylliums.Ok. I guess send them over when you are done with them and I'll ask subwoof again to send his 1.5-inchers.
It may be that Lansing Heritage Forums needs an R & D budget.I'd really like to have a private conversation with Don about that before anything more is said about it.

[Guido]

I think the next steps needed are: A network option for the 2450 aquaplased and a horn solution and network for the 1.5" berylliums.


I second this!
Let's go this way Giskard

[John W]

I can turn a couple horns for a 1.5 in drivers. The lathe is all ready to go.
I would need someone to come up with a good profile, though.

[andresohc]

I am interested in these circuits also. I only need the top half (2122H, 2307/2308/2425, 2405). I have built a center channel box (without a crossover) but not tested it. It has two 2122s. I hope to build a pair of front channel speakers next spring or summer with the latest equivalent circuit . I have to sell off some more of my JBL bookshelf speakers to fund it, but would be very interested in the latest design of the 3145, primarily above the 2245s. As I have posted before I plan on trying to drive the 2122s down to the upper range of the SUB1500s. I will have a pair in sealed boxes. If you see 4313As and L112s in the market place thats why.
I have all the components for the 4345s plus a pair of sub1500s awaiting crossovers, money, and time. I will contribute what I can toward the new design. Thanks for all the help either way Giskard and Ian.

[Ian Mackenzie]

If anyone is intertested I am going to look at designing a diffraction wedge wave guide system for a customised HF and UHF elements of the 4345.

Using customised wave guide techniques it is possible to overcome some of the major shortcomings of the original design:

Time alignment of acoustic centres.
True acoustic impediance matching of drivers at crossover point.
Control of early reflections.
Significantly reduced distortion.

I have not determined what the drivers will be but the use of wave guides frees up the use of very high performance direct radiators is such an arrangement.

Ian

[X_X]

Ian,

Count my hand.

I seem to recall you mentioned using different HF and UHF drivers in another thread and I can't seem to find it now. What were the (other) drivers you were thinking on?

I might lend a hand with your project. I am not as technical, but I'll wake to make a contribution before it goes a over t. Perhaps the first thing would be to find suitable drivers, hmm?


Nate.


**** I already reconed- didn't see your 2245 core offer until it was too late. Thanks anyway, mate. Swan is wonderful. I was a bit bargy. Cheers.

[Ian Mackenzie]

Nate,

Hi over there. I will keep you in the loop. It will be a long term project

This a nothing new, Duntech used a similar approach in their designs.

The thing about it is looking at amplitude response and power response is a very one dimensional view of what a loudspeaker does when you start to serious model the system as a whole. By apply some clever concepts you can realise a more ideal system.

I a not suggesting anyone hack into their 4345's or that it is a has been system.

Far from it but for the diy speaker builder there are some wonderful opportunities. You just have to open you eyes!