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View Full Version : NEW 1.5 inch horn for 4345 / 4343



subwoof
04-05-2004, 09:36 PM
Ok - here's the situation.

JBL designed the large studio monitors back when all that was available were:

(A) The small format ( 2420/21 and 2425 ) 1.75" coil diaphram that had a 3 bolt 1" exit.
(B) The large format ( 2440/41 and 2445 ) 4.0" coil diaphram that had a 4 bolt 2" exit.

However since then the newer 1.5" format drivers ( with both the 3" and 4" coils ) have been introduced and they are capable of *significant* advantages in response, distortion, power and of course, weight.

So it sounds like a good idea to stick them in the 4343 and 4345's to improve the critical upper midrange.

The additional benefits are:

(I) Much shorter length from phase plug to lens ( the 1.5" drivers have NO integral horn )

(II) Newer diaphram materials ( beryllium and Coated titanium ) along with newer geometry aluminum AND improved adhesives.

(III) Newer Magnetic material that reduce the weight from 1/3 to 1/10 of the original !!

(IV) Newer phase plug geometry that reduces cancellation and distortion - much smoother response

**But**

JBL did not make a compatible horn that fit these new drivers that could be retrofitted into the older monitors. The only way to do this was to get a pair of 2311's ( good luck ) AND a pair of 2330's ( good luck X5 ) and redrill the 2330 to accept the new driver. And even when this is done the horn length is still appox 7" ( see table below )

So, with a little determination, a pair of sacrificial 2307's and basic power tools, we created a new horn that fits the old monitors and is only 4.75" long.

The process was straight foward:

(1) Built a jig that allowed a standard bandsaw ( with a metal cutting blade ) to lop off the original flange and some of the horn.

(2) Cut the new flanges from 3/4 Baltic Birch plywood ( 5.75" dia ) with a router circle cutting jig.

(3) Bore a 1.5" hole in the center with a $$ forstner bit *** USE A DRILL PRESS ***

(4) Rabbet a recess to allow the horn to fit into - dimensions on drawing are appox. ( the castings were a little different )

(5) Drill mounting holes with forstner bit on drill press - Note that 2 radiuses are used ( 8 holes total )

(6) Clean surfaces and remove old paint from horn.

(7) Assemble the parts with fiberglas resin and put 1/8 nylon rope into the gaps.

(8) Sand, primer with rustoleum 7220 and paint with 7769 texture black paint.


Actual horn length table:

2307 / 2421 is 10 1/2 " ( 8 1/2 + 2 )
2311 / 2441 is 7 1/2" ( 4 3/4 + 2 3/4 )
2313 / 2451 or 2435 is only 4 3/4"

The final product worked out well and I hope to have them in the 4345's this weekend with the new 2435 drivers.

Next project will be routing a horn sub baffle into the 4345 to allow multiple horn combinations with individual panels ( based on the 2332 cutout )

sub.

subwoof
04-05-2004, 09:37 PM
The Jig

subwoof
04-05-2004, 09:38 PM
The 2307 after cut off:

subwoof
04-05-2004, 09:39 PM
The new wood flanges:

subwoof
04-05-2004, 09:40 PM
The new flanges all routed + drilled. The horns prepped for assembly:

subwoof
04-05-2004, 09:41 PM
Assembled:

subwoof
04-05-2004, 09:42 PM
Sanded + finished:

subwoof
04-05-2004, 09:49 PM
Comparing the 3 horns:

L to R:

2307 ( 1" exit )
2313 ( 1.5" exit )
2311 ( 2 inch )

Note that the overall depth of the 2311 and 2313 is the same.

speakerdave
04-06-2004, 06:21 AM
Boy, subwoof, when you answer a question you don't fool around!

That's a very crafty job of work--thanks for sharing it.

David

subwoof
04-06-2004, 09:02 AM
Well giskard the *next* batch will be with welded aluminum flanges and I will have a machine shop make up a bunch....

In the process of test fitting these in the 4345's ( along with many horn/driver combo's ) I found that the larger diameter 1.5" ( 2451 ) and 2" ( 2450 / 475 / 2441 ) WILL fit with the 2311 horn.

BUT I don't think they will in the smaller 4343 ???

It's a snug fit but it's possible that some production runs might be different???? I have seen some pretty poor craftsmanship / tolerances in some of the cabinetry from that era....
:(

sub

herve M
04-06-2004, 10:06 AM
:) good good !!!
the exponential horn is the best ! Aperture, warm, fine sound.
The biradial horn is superior for imaging, but the sound is sad and weak.
Vote for exponential horn resurrection !!!
HervéM

herve M
04-06-2004, 10:33 AM
:) :) :) :) :) HI hi hi!!
Memory memory:
Ian McKenzie 2344a out !
(general: 2344a versus 2307/2308+2405)

and monitor preference poll (05-2003): 434x: 45% and 433x 15%
and 4430 20%.

and me: 2344 PAIR IN CARTON: to be sold.
:smthsail: :smthsail: :smthsail: :smthsail: :smthsail:

boputnam
04-06-2004, 10:57 AM
Originally posted by subwoof
In the process of test fitting these in the 4345's ... I found that the larger diameter ... 2" ( 2450 / 475 / 2441 ) WILL fit with the 2311 horn. Hey, sub...

Very impressive work, and smart thinking!

A question: I scoped-out the 2441 / 2311 possibility for my 4345's and the motor diameter was too large to fit - it would take modifying (I thought...) the rear/top of the 2122 doghouse for the fit. Not true? :hmm:

Mr. Widget
04-06-2004, 11:27 AM
Originally posted by Giskard
:rotfl: Only if you have hearing damage my friend :)
I can see going back to the exponentials in my Senior Citizen years.

Yeah Baby! :thmbsup:

Hey silly rabbit, exponential horns are for kids!:D


Widget

Ian Mackenzie
04-06-2004, 01:21 PM
Lager.....Na na Victoria Bitter or Guinness thankyou...Fosters makes me Fart...hang on so does Giuinness....whatever


Hey Subwoofer,


Might have to book an audition.....around 12 to 20 May if possible

An invite please.

Ian

boputnam
04-06-2004, 01:31 PM
Originally posted by Giskard
...The more lager, the better the 2307's look... :smsex: Giskard!! :scold:

Guido
04-06-2004, 01:47 PM
Originally posted by Giskard
The more lager, the better the 2307's look... Ooops, I mean sound :D


Pah Lager.... Pils or Weissbier bitteschoen!

The more beer I drink the more I tweak around with my 4343 and when hearing them the next morning: What have I done :confused: :confused:

Always shocking what alcohol can do with our whatever :bouncy: :bouncy: :bouncy: :cool: :cool: :cool:

Ian Mackenzie
04-06-2004, 03:07 PM
I wonder what the 4344MK11 sounds like with the 275 driver....thats another option.

I have to pull the 4345s down this weekend and will try damping the blastard 2307.........should I take a hacksaw to it........in anticipation...:rolleyes:

Pity about the 2344, can't even use it in MTM 12'inches seperation..too much say Tim....

I prefer a nice Cab Sav when I tweeking..

Ian:D

boputnam
04-06-2004, 03:32 PM
Ian, dood...

All you need is to JBL Blue them baffles...! :nutz:

Guido
04-06-2004, 03:41 PM
Originally posted by Giskard
I use mine as toilet bowl covers. They look hilarious. :rotfl:


:nutz: :nutz: :nutz:

subwoof
04-06-2004, 04:11 PM
{ Edited to avoid injuring sensitive eyes }

And JUST how do you get them to stay up ?

Or are you conditioned (not ) to leave them down....

Hmmmmm

speakerdave
04-06-2004, 07:57 PM
And this thread started out so very nicely.

4313B
04-07-2004, 09:01 AM
You're absolutely right. Many of them do. I cleaned my posts up...

subwoof
04-10-2004, 07:42 PM
Here is the new horn with a 2435.

Positively dwarfs it...

:)

subwoof
04-10-2004, 07:44 PM
And here it is with a 2450SL ( aquaplas coated 4" titanium diaphram with Nd magnet ). This driver is used in the array and DMS-1

NOTE: the magnet cover was removed to accurately show the distance from top plate to exit. Only 4.75"

sub

Ian Mackenzie
04-10-2004, 07:51 PM
Nice stuff Mike,

Have you had a wiff of the sound yet?......

We needs to know Man, we needs to know.

Ian

subwoof
04-10-2004, 09:56 PM
soon man, soon....

When we get above 50 degrees here in spring, and the ground is not frozen / soggy, we tend to administer the awakening rites to that great home depot money soak:

THE LAWN

Which entails multiple teenage boys ( for our teenage daughters to fawn over / bother with ), delivery of copious amounts of chicken wings + fluids.

And then self-administering refreshing anti-freeze into the bloodstream while downing tylenol to minimize the middle age muscle ache blues.
:cheers:

Which puts the speaker tweaking on a sidetrack.....

I will let you guys know this week. I need to:

(A) Compensate the impedance of the driver ( the 2450Sl is 8 ohms ) on the crossover.

(B) Rout / install the new removable horn baffle ( to allow interchangeability from the FRONT with the conical and array horn ). The horns come in tuesday afternoon. I feel that the 2332 will outshine the conical horn/lens and want to A-B them directly in realtime.

(C) Finsh assembling the power rack ( dual crown delta omega / crown SA2 / JBL 5234A and the crown SL2 ). I want to judge these with the complete biamped power setup not just the SA2 in passive mode.

(D) Reinstall the 2405 tweeters ( new diaphrams and plexi centers...)

...sigh....

sub

subwoof
05-17-2007, 11:09 AM
3 years later.....

I see that the pictures I posted to my website did not re-appear when I checked ( I guess the links that are embedded into my posts are gone?? )

Anyways for those of you who want to dig and view, here is a list of the pictures:


http://northernacoustics.com/ebaypix/2313-2435.jpg
http://northernacoustics.com/ebaypix/2313-H1.jpg
http://northernacoustics.com/ebaypix/2313-H1A.jpg
http://northernacoustics.com/ebaypix/2313-H2.jpg
http://northernacoustics.com/ebaypix/2313-H4.jpg
http://northernacoustics.com/ebaypix/2313-H6.jpg
http://northernacoustics.com/ebaypix/2313-H7.jpg
http://northernacoustics.com/ebaypix/2313-H8.jpg
http://northernacoustics.com/ebaypix/2307-2313-2311.jpg

When I get my horns back from giskard ( hint hint ) I will post a picture of a 2450SL attached to one of them.

sub

hjames
05-17-2007, 11:23 AM
I see that the pictures I posted to my website did not re-appear when I checked ( I guess the links that are embedded into my posts are gone?? )

When I get my horns back from giskard ( hint hint ) I will post a picture of a 2450SL attached to one of them.

sub

Part 2 -

I've uploaded copies of Subwoofs pictures directly to the Lansing forum

hjames
05-17-2007, 11:28 AM
Part 1 -

I've uploaded copies of Subwoofs pictures directly to the Lansing forum

Thom
05-17-2007, 11:39 AM
Am I grateful for those last posts. Saved me hours of digging in my computer.

Thom
05-17-2007, 11:49 AM
Yes, sorry for taking so long. There is actually a right way to integrate this horn and there is the quick and dirty way. The quick and dirty way probably works good enough with digital signal processing applied.

For those who might hesitate to cut a 2307 or H91 down to the 1.5" exit for use with 1.5" c.d.'s, don't. JBL did just that to make the 2311/H93 for 2" exit c.d.'s. Don't use the 2312 or H92 though, the flare rate isn't "right" for this application. Also, none of these horns are for use below ~ 1 kHz.

Is it a matter of the new tapper being wrong for the old taper? Excuse me if taper isn't the correct term, I'm not sure if it is or not. How bout when you want to put a 1.5 on a 1" horn. Can you cut it where it's large enough drill the flange and weld (or glue) it back on. Or are there special rules there. Also do you change the low cut off because you've changed the ratio of the input to the output? Sorry for the freshman questions but I've been wrestling with them and they seemed very related.

hjames
05-17-2007, 11:59 AM
Is it a matter of the new tapper being wrong for the old taper? Excuse me if taper isn't the correct term, I'm not sure if it is or not. How bout when you want to put a 1.5 on a 1" horn. Can you cut it where it's large enough drill the flange and weld (or glue) it back on. Or are there special rules there. Also do you change the low cut off because you've changed the ratio of the input to the output? Sorry for the freshman questions but I've been wrestling with them and they seemed very related.

I'd suspect there are some heavy mathematics behind the final correct solution for this kind of mod ...

Or, as Giskard mentioned, the Quick and Dirty approach.


Sorry - all I can think of is flow testing an intake manifold - smooth is better, gentle curves and gradual tapers.

Isn't audio related to airflow over the surfaces?

SMKSoundPro
05-17-2007, 12:57 PM
Question:

What about manufacturing a conical shaped horn out hardwoods with the correct flare rate and length and ending in a 1.5" mounting flange. Seems like a lathe turning operation.

Or:

Machining the above mentioned horn out of an aluminum billet.

It seems as if it would be similar to making a birch bowl on the lathe, that so many turners do here in Alaska.

It could be turned out of Beautiful hardwoods, or laminations of different species, and end up as a real show stopping piece of art.

I could have my friend, the Admiral, turn one from a billot of al, or maybe brass.

Is this idea plausible, and has anyone else tried it?

Scott.

subwoof
05-17-2007, 02:21 PM
Designing ( horns ) is not an exact science - as G.T. said, it is a series of compromises. Even the newest computer aided manufacture PT horns are a series of different tapers and surfaces that flow into a single mouth...that is some serious math and even THEN it does not work well for some combinations!

The length, throat size, mouth size, the throat to mouth ratio, the flare rate ( x, x2, x3 ) ( conical, exponential, hyperbolic ) ALL come into play.

And then you have to blend it in between the mid and UHF components that are near opposites in design and function.

This endeavor was to use newer drivers *without* messing up the baffles on the large 4 ways and not change the flare rate of the horn. This approach was the best compromise I could come up with and with a shop full of tools, fairly straight forward.

I was never in love with the idea of having HF smash up against a series of plates ( plastic, wood, metal, etc ) and coupled to a horn with a small format diaphram ( 1" ) that is now very expensive and fragile.

However if Giskard deems it acceptable ( dirty or otherwise ), I can dig out the jig ( assuming it survived the big purge last year ) and cut up horns for others. Bondo and paint are the fun part left for the owners..:)

eeehhhaaahhhhhhhhhhhh

sub

Ian Mackenzie
05-17-2007, 03:22 PM
Have you thought of acquaplasing the 2405 diaphagm's if you going to that sort of trouble and expense. That driver is totally dated and flawed in comparison to current soa compression drivers.

If run the tad full range it might be interesting.

boputnam
05-17-2007, 05:03 PM
If run the tad full range it might be interesting.And I have thought about that.

However, you might have noticed on Widget's masterwork, he finally included a TAD tweet, too.

Earl K
05-17-2007, 05:26 PM
Hi

- A 2311 with an added 1.5" to 2.0" adapter ( available only from P-Audio, now that Selenium no longer makes them ) has @ 2" of extra horn length ( measured perpendicular to the phase plug ) when compared to just a 2311 or subwoofs' 2313 ( the cutdown 2307 ).
- This extra 2" is still a bit less than what the old 2441 ( with 2311 ) has in total throat depth / similarly measured inside the drivers' throat and going back to the phase plug.

- The extra 2" does make a difference in MF loading ( over the 2313 ).
- This 2-piece approach would be my preferred way to go, if I actually wanted to retrofit a 1.5" exited driver into a 434x 4-way.

- This 2-piece combo will load to 1000 hz ( though maybe needing the help of a 2-pole bump filter / FWIW: the DD66000 uses this approach of gentle MF boost, "see the OM" ) . 1000 hz to 10K is obtainable ( and IME, quite desirable if one has a quality compression driver that's worth listening to ).

- & yes, a little bit of bondo to smooth any rough joints is quite likely desirable.

:p

4313B
06-20-2007, 07:57 PM
Here are some measurements of the 2421B/2307/2308 and the 435Be/2313/2308

The second graph is somewhat normalized.

The impedance curves are completely different and I'll post them when I have time.

I've decided to put this whole 435Be/2313/2308 variant on the far back burner for now due to the shear number of deliverables that I am in hot water for. These 2313's are headed back to subwoof next Monday.

Thank you subwoof.

The TAD TD-2002 on the 2307 option is pretty damn nice. I have no idea what the cost differential is though.

Thank you Mr. Widget.

Robh3606
06-20-2007, 08:37 PM
Thanks for posting that! Reminds me I have to order my horns!

Rob:)

subwoof
06-21-2007, 10:03 AM
Just leased a 30 X 60 building for the shop(s) so after a 2 year downtime and having stuff housed in 3 locations for over 4 years, the woodshop will be cranking out cabs later this summer.

And during the move the custom bandsaw jig was found for the 2307 cutting so any forum members who are interested, send me a PM.

And I found box after box of horns ( no 2307's though ) that were squirreled away for future projects and of course I won't need them all so when the dust settles, I will post what's available on the marketplace forum.

And thanks to giskard for elbowing the other projects aside for a quick analysis on the 2313 horns. It looks like they will work OK with the stock passive crossover frequency points of the larger 4 ways.

:o)

:cheers:

spkrman57
06-21-2007, 10:27 AM
And thanks to giskard for elbowing the other projects aside for a quick analysis on the 2313 horns. :cheers:


I wonder how he finds the time to do all these things!

Ron

sourceoneaudio
06-21-2007, 10:34 AM
I was under the impression he was semi retired............? :blink:

hjames
06-21-2007, 10:57 AM
I wonder how he finds the time to do all these things!
Ron

Perhaps ...?

a. He is really dedicated to this stuff and, despite the frustration, still tries to give and share info with those who he feels can really appreciate it

b. He has a gadget he got from Nikola Tesla and cloned himself ... ala The Prestige

c. Wormhole technology

d. He has an espresso coffeemaker and rarely sleeps

e. He is part of a business and "Giskard" is just the corporate image, like the Maytag repair man - many people may be playing the role of G*

f. Sidney H. pays him the big bucks to be here (might be related to e. )

g. perhaps he has a nice life offline and longs to be there more than here ...

(Said in playful support, no offense or slights intended to G)

sourceoneaudio
06-21-2007, 11:04 AM
I still think he is retired, and can't get enough. (Eats, Sleeps, and Drinks JBL) :bouncy:

4313B
06-21-2007, 11:11 AM
I wonder how he finds the time to do all these things!I don't and people are angry with me. I don't blame them.

opimax
06-21-2007, 03:42 PM
its worth the wait!!! you weren't taking emails when I sent my thanks so I have to do this in public, THANKS!! :)

From experience

Mark

subwoof
07-21-2007, 07:20 PM
Does anybody know where giskard is ??

He has had my 2313 horns and a number of expensive 2435Be drivers since *JANUARY* and hasn't replied or posted on this site in 3 weeks???

Vacation?? Jail? Moved?

If anybody knows, please PM.

sub



"Giskard: I don't and people are angry with me. I don't blame them."

4313B
07-25-2007, 06:20 AM
I'll try to get everything out the door to you next Monday.

BTW - It seems a bunch of you guys bought these drivers from the same second-hand source. Kind of weird to see these drivers from all over the country with the same handwritten field notations on them.

subwoof
07-25-2007, 09:11 AM
Yeah it seems that that seller was stripping apart a lot of early issue vertec's or was the recipient of the parts. One that I received had a shifted magnet but it was promptly replaced. He sold at least 30 of them but I have never seen the 8's. Wonder where they are??

Anyways welcome back from your vacation and I hope the pile of projects isn't too overwhelming..

:cheers:

sub

subwoof
09-03-2007, 10:44 PM
Well it's 2 months later and I still haven't seen my 2435 drivers or my horns even after speaking on the phone directly with Giskard.....

it's been 9 months since I sent them..:(

Does anybody else have items in limbo also???

sub

richluvsound
09-04-2007, 04:24 AM
Hi subwoof ,

did you ever get the flange welded on the horns ? I'd like to try the same mod with a dusted 2435. Good luck with it and please keep us posted.

Rich

subwoof
09-04-2007, 01:43 PM
I epoxy'ed the wood flanges to the cut off horn. I didn't have access to aluminum welding back then and wanted them right away.

But alas they are MIA so I might have to make another set so I can try out the 2452-SL's on the 4341's.

sub

subwoof
09-16-2007, 06:31 PM
Well I finally got both the horns back from Giskard and a set of the newer Nd coated dia drivers ( 2452H-SL ) from ebay so THIS looks like a potent drop-in combo to try out in the 4341's later this week....

:cheers:

sub

richluvsound
09-16-2007, 07:49 PM
Hi Sub,

they look the dogs sub. I look forward to your impressions. The dust works well in the ti 2425 so they should sound pretty sexy.

rich:applaud:

hjames
09-17-2007, 05:11 AM
Well I finally got both the horns back from Giskard and a set of the newer Nd coated dia drivers ( 2452H-SL ) from ebay so THIS looks like a potent drop-in combo to try out in the 4341's later this week....

:cheers:

sub
Thats looks like a brutal combination - short and deadly! Woah!
By all means, let us know!

4313B
09-17-2007, 07:59 AM
Well it's 2 months later and I still haven't seen my 2435 drivers or my horns even after speaking on the phone directly with Giskard.....

it's been 9 months since I sent them..:(

Does anybody else have items in limbo also???Yes, unfortunately there are quite a few deliverables still to work through. I should have sent the horns back separately from the 2435's. I have seven more 2435's to do out of a batch of thirty-nine. All were done with the correct aquaplas and ferrofluid. Two of yours and one of Guido's were the only ones that suffered the doublestick tape creep. It took me nearly thirty minutes just to get the diaphragm out of Guido's 2435.

The 2452 looks more fitting physically than the 2435. You'll have to run a response curve with that combo and the network and compare it to stock. I suspect there will be a new run on 2452's like there was a run on 2435's. :p Perhaps a run on these custom exponentials as well. I know that I'd take a pair just for fun but only if I could find a pair of L94 serpentines to go along with them and that probably isn't going to happen. :rotfl:

speakerdave
09-17-2007, 08:40 AM
I think the 2452SL is a good bet for the Optimized Aperture horns (2332, 2352 and 2381) and the PT waveguide, to take advantage of the HF dispersion afforded by the design. If you want to use a 4" aquaplased driver for the 434x application, where the HF dispersion of the throatless driver/OA horn combo is being discarded by using the round exponential, I think the 2450 with powdered diaphragm is a better bet, because the driver throat with the 2311 is longer.

David

4313B
09-17-2007, 09:09 AM
You might be right speakerdave.

It should be noted that there is alot to be said for the stock large format 43xx monitors with just the aquaplas and bi-amp only cc network tweaks we've discussed so far.

speakerdave
09-17-2007, 12:43 PM
By the way, for anyone messing with the 2452SL, the tech sheet for the 2452H/J says bolts are 1 and 1/4. That's way to long. 1" is too long; I'm going to try 3/4.

David

Edit: 3/4" just works with a lock washer on my horn (2333).

speakerdave
09-17-2007, 01:20 PM
I thought subwoof cut the 2307 for OA drivers to essentially include the throat length
that would already be there for the 2450... i.e., OA driver + custom horn being the
approximate equivalent of non-OA-2" driver + 2311 (in regard to throat+horn length). . . .

I think I've figured this out. I'm not sure the 2307 and 2311 have the same expansion rate. It doesn't add up anyway. Remember, the original setup had the full length of the 2307 plus a non-throatless driver. The 2311 plus the 2450 already compromises that. The "2313" with a throatless driver goes even further. Perhaps part of the merit of the original setup with the coated diaphragm is that the total horn length is what it should be. Best I've heard so far in this application is the original horn with a 1" TAD driver.

David

4313B
09-17-2007, 02:16 PM
I think I've figured this out. I'm not sure the 2307 and 2311 have the same expansion rate.As I've previously posted, they do.
JBL merely chopped a 2307/H91 down to make the 2311/H93.
It's the 2312/H92 that's "all wrong" for this kind of activity.

Best I've heard so far in this application is the original horn with a 1" TAD driver.I think that TAD is a really nice driver.
G.T. had some input into this whole thing and I came to the conclusion after I messed with several combinations that the stock Al or Ti diaphragms with aquaplas applied and alnico cores offered the best balance and bang for the buck with the TAD being a very good option at increased expense. Of course, you guys are getting these 2435's and 2452's at substantially reduced costs so I can see why you would want to try them out in various scenarios.

4313B
09-17-2007, 02:41 PM
heh.. well I've apparently killed too many brain cells... :blink:
went back and re-read post #1 where the 2311 and "2313" are listed as:
Wouldn't the 1.5" throat version need to be 7 1/2" (ala the 2311+2330) unless
the 2313 flare is now compound or otherwise modified?Why? To maintain horn length? It simply doesn't matter, the system is jacked anyway in that respect so it just doesn't matter. I'd be more worried about the frequency response and impedance curve of any new combination so as to modify the network accordingly.
I guess it's moot. I'm not going to go cut up horns for this. Sorry for the detour.Agreed. I'm not either and I abandonded the network design for the 1.5" 2435/435Be-based combo accordingly.

subwoof
09-17-2007, 02:52 PM
The math involved in this horn mod was to simply get the horn cut off to the point that the resultant horn + small thickness of flange ( to be beveled later ) was equal to 1.5"

In my initial posting(s) I measured the actual phase plug to horn exit for all 3 combo's:

2307 / 2421 is 10 1/2 " ( 8 1/2 + 2 )
2311 / 2441 ( or 2450 ) is 7 1/2" ( 4 3/4 + 2 3/4 )
2313 / 2451 or 2435 ( and now 2452 variants ) is only 4 3/4"

I feel that the larger, more robust 4" diaphrams will handle any excursion / rolloff anomalies caused by the shorter horn. This isn't a football stadium, full power wide range app for this driver combo....

Remember that the "time alignment" issue for the long horn is also reduced to almost the depth of the 15 or 18 cone!

I have all of these horns and combo's - and the 2311/2330 had the same flare as the 2307 but the extra flange thickness ( and the fact the 2330 is for the ALTEC 1.4" ) changed the overall length a little.

The 2312 IS a different horn flare and should not be in this discussion.

In all this is just an experiment of modest goals - not the engineering pancea to re-invent the wheel..:)

sub

4313B
09-17-2007, 03:00 PM
The math involved in this horn mod was to simply get the horn cut off to the point that the resultant horn + small thickness of flange ( to be beveled later ) was equal to 1.5"And everyone should note that that is completely acceptable.
I feel that the larger, more robust 4" diaphrams will handle any excursion / rolloff anomalies caused by the shorter horn.Not an issue given that you should cross them at 1kHz or higher. What you will do is play signal through the midbass driver and this horn/c.d. combo at the same time and measure the frequency response (make sure the horn/c.d. combo has its sensitivity brought down in line with the midbass driver using an L-Pad). Where there is a sharp dip in response you will place your intended crossover frequency. It should be around 1.2 kHz (If I remember correctly I got 1.275 kHz with the 435Be).
Remember that the "time alignment" issue for the long horn is also reduced to almost the depth of the 15 or 18 cone!Only really matters with respect to the midbass driver, whatever that may be. The 2405/077 is what it is and jacked by design. No worries there. This stuff just works.
In all this is just an experiment of modest goalsUnderstood.

Ian Mackenzie
09-17-2007, 03:25 PM
Interesting.

For what its worth I have heard the aluminium (2421), titanium (2425), acquaplas with titanium and stock Be diaphragms (Tad 2002) very recently in the 4345.

IMHO the diaphragm material is the key to improved performance, not the horn length or rear diaphragm piston area in this system. The coated titanium is better by an audible margin and Be (Tad) is noticably better again. They have more resolution.

Unfortunately the Tad 2002 has been discontinued. So the only option for you guys is the JBL Be equiped 2435 driver (0435) but it means modifying the 2307 as discussed by Subwoofer.

(I heard the Be 2435 at Rob's but with another JBL PT horn)

Ian

4313B
09-17-2007, 03:37 PM
So the only option for you guys is the JBL Be equiped 2435 driver (0435) but it means modifying the 2307 as discussed by Subwoofer.Yeah but it really needs another network mod too.

What does TAD have as a replacement?

speakerdave
09-17-2007, 03:41 PM
. . . . G.T. had some input into this whole thing and I came to the conclusion . . . . stock Al or Ti diaphragms with aquaplas applied and alnico cores offered the best balance and bang for the buck . . . .

Certainly can't beat the price of that.

David

subwoof
09-17-2007, 03:42 PM
Grumpy: The 2313 horns that I made have a flange thickness of 3/4 inch.

That is 1/2 an inch thicker than the flange on the 2311.

sub

richluvsound
09-17-2007, 04:34 PM
but, you already figured that out.

:blink:


Where do I measure from ? the front of the flange,the back of the flange , the front rim of the horn . :o:

Rich

subwoof
09-17-2007, 05:59 PM
Put said horn face down on a flat surface.

Measure vertical height to the surface the driver will bolt to.

Done.

This *is* the length of the horn.

Now the older model drivers have a short internal waveguide/horn/throat ( whatever term fits your definition ) that is located after the phase plug but before the exit and this *adds* to the effective horn length in this situation because it is after the phase plug and has the SAME taper ( slope ).

The newer drivers do not have this.

ok?

sub

Mr. Widget
09-17-2007, 09:31 PM
What does TAD have as a replacement?A couple of years ago they discontinued all of their studio monitors, last year they discontinued all of their horns and now they are discontinuing many of their woofers and compression drivers... it wouldn't surprise me if they discontinue the whole line in the next year or two.

It is really too bad... years ago they spirited Bart Locanthi away from JBL and now it seems they have spirited away some of JBL's bean counters too.:(


Widget

richluvsound
09-18-2007, 03:45 AM
Hi Sub,

I want to double check before I give it the chop. It measures 4.75" I'll be welding the flange !

Rich

subwoof
09-18-2007, 08:40 AM
Do not chop yet....

the cut-off point is on a section of the horn's inside diameter that is LARGER than 1.5" for my 2313 project.

If you look at the pictures I posted, you will see that the now-cutoff horn sits into a recess on the wood flange. The section of wood that is now between the horn and where the driver mounts has to be hand-beveled to get the correct 1.5" dimension.

IF you are going to simply weld a new flange on the horn, and made the new flange slide over the outside, then you would cut off the horn at a different point ( where the inside diameter IS exactly 1.5"

NEITHER of these lengths are 4.75" and until I re-check my templates and horn stash today, unknown.

I will post some additional info in a few hours.

sub

richluvsound
09-18-2007, 08:51 AM
Hey Sub,

the patient is still intact.

I'm hoping as copies these horns maintain the original's wall thickness.



Rich

subwoof
09-18-2007, 11:50 AM
He snorted and....Well here's the actual results. Everybody was both right and wrong.

btw - rich: your tape line is 4.375 not 4.75..:)

Both the JBL 2311 and my 2313 are the same depth ( 4 and 3/4 inches ) ( 4.75 )

All 3 horns ( 2307,2311 and 2313 ) have the same exit flange dimensions.

By using the easiest method I could find, a shop ruler that is exactly 2" wide, I stuck it into a 2311 horn that was face *up* on a sheet of plywood.

As expected, it reached the bottom and the depth was 4 and 5/8 inches ( 4.625 )

WHEN I stuck this same ruler into the 2307, it only went down to 4 and 1/4 ( 4.25 )

But SURPRISE SURPRISE when I stuck it into my 2313 ( which was a cut off CONSUMER H91 ), it only went down 3 and 1/4 ( 3.25 ) !!

Therefore, the slopes *cannot* be the same. Sorry giskard.

Now since these are not easy or cheap to come by anymore, cutting them lengthwise with a bandsaw and drawing the slopes was out of the question. It appears the 2311 is a little more conical than the 2307 when eyeballed. And the 2307 was more conical than the consumer H91.

Now for some pix - I REALLY HATE the so-called intelligent focusing on these digital camera's. If I could put a digital back on my 35mm bodies ( and use the 16+ lens I have ) THEN they will be clear....

I included a measurement picture of the pieces I cut off. THIS is why you never throw away JBL..:)
It is 4 and 1/4 ( 4.25 ) long.

In summation, you will need to actually MEASURE your own horn to see how far down the magical 1.5" depth is and cut off accordingly since it appears that there were many casting differences between models ( and probably years ).

Hmmmmmm

sub

4313B
09-18-2007, 12:00 PM
Therefore, the slopes *cannot* be the same. Sorry giskard.Sorry Greg. I merely passed along the information. And to be fair, remember that he is going on memory of a 25 year old product. He's done a veritable ton of stuff since. You want to use the fastest taper possible so whatever horn is going to give you that is the one to use.

BTW - What are the depths of the throats in the 2420 and 2440?

As expected, it reached the bottom and the depth was 4 and 5/8 inches ( 4.625 )

WHEN I stuck this same ruler into the 2307, it only went down to 4 and 1/4 ( 4.25 )

But SURPRISE SURPRISE when I stuck it into my 2313 ( which was a cut off CONSUMER H91 ), it only went down 3 and 1/4 ( 3.25 ) !!This truly is bizarre. I wonder what the taper is in the brand new "2307's" I sent to richluvsound... they came out of the 4344 MK II if I remember correctly. I guess I'll measure the 2307's I have when I get home tonight and see "which ones" I have. Now we have to hand pick these things?

subwoof
09-18-2007, 12:26 PM
I happen to have one of each on the "WTF" table.

the bakelite throat of the 2440 is 2 and 3/4 ( 2.75 ) inches.

the aluminum throat of the 2420 is 1 and 7/8 ( 1.875 ) inches.

Both appear to be conical or if exponential, a damn small flare.

I don't have a 2440 throat out of a driver to lay a flat edge inside of and don't have a thin enough ruler for the 2420. But I will check soon.

I have (2) 2307's in my 4341's ( this is the one I measured ) and 2 NOS from the late 80's in storage. Time to check..:)

sub

4313B
09-18-2007, 12:39 PM
Well that will be truly jacked up if the H91's are measuring differently than the 2307's. :rotfl:

But then we can always fall back on that "JBL continually engages..." clause. :p

subwoof
09-18-2007, 01:03 PM
I have seen the "casting" differences in the (3) generations of the 2345 ( the first had no flange on the top ), The 2340 ( none ever fit into another's cutout...grrr... ) the 5039 / 2343 horns as used in the paragon / 2395 lens assy, and the 2328 throats.

Since they appear to be sand casts (??) that were welded together, maybe they changed over long-term use or different "masters" were made at different times.

And CNC machines weren't around then and the designers at JBL had to descend from the mountain with white robe and sandals to impart wisdom to the shop floor without so much as a 4 banger calculator since a slide rule was a little complicated....

We need an old-timer who was privy to the mfgr details to answer this one.

sub
:cheers:

richluvsound
09-18-2007, 02:14 PM
S
BTW -
This truly is bizarre. I wonder what the taper is in the brand new "2307's" I sent to richluvsound... they came out of the 4344 MK II if I remember correctly. I guess I'll measure the 2307's I have when I get home tonight and see "which ones" I have. Now we have to hand pick these things?

Hi Giskard,

now I have to turn the band -saw off:banghead:. I wait on this one and see what learned come up with:p.

Rich

subwoof
09-18-2007, 02:47 PM
Some time ago I found (4) black painted 2311 ( H93 ) knock-off's at a music store that also have 2307 ( H91 ) clones I don't know what the brand was ( not mcCauley ) but they were physically interchangeable with the JBLs.

Since the horns I used back in 2004 didn't have tags, and the spot where the evidence would be to see if they were there was painted over, I cannot be 100% certain that this was a pair of JBL's I chopped up but I was pretty sure..

If anyone out there has a pair of original L91's that can measure down the snout with a 2" rule like I did, posting that info would go a long ways toward solving this riddle.

Rich: All you need to do is get a 1.5" wide piece of metal and lower it down the mouth of the horn to measure your cut-off point. On the factory 2307 I have here that is exactly 6 inches and that would be just like the mark on the pix you posted.

sub

**update** I have a pair of original H91's being sent to me by my brother so the answer will be know hopefully by the weekend.

Earl K
09-18-2007, 03:15 PM
Some time ago I found (4) black painted 2311 ( H93 ) knock-off's at a music store that also have 2307 ( H91 ) clones I don't know what the brand was ( not mcCauley ) but they were physically interchangeable with the JBLs.


- If I read this correct, your 2313s may have been made out of off-shore clones. That'll be a real kicker for others to duplicate .

- I have some of these 2307 clones / I believe they were distributed, across N. America by Image ( Audio,,, Sound,,, or Communcations ? / the same people who used to handle Radian diaphragms ) . I've hacked up a few of my clones ( flanges ) since they weren't bonafide 2307s. They are painted in a black crackle type finish, just like a H91s.
- The H91 clones measure down to @ 3.5" of depth, at the 2" wide point ( using a stiff 2" by 3.5" business card as a ruler ) .

:)

ps : This same outfit also offered the "L11" , which was the lense equivalent to the L91 . They're all Taiwanese made .

richluvsound
09-18-2007, 03:23 PM
Sub,



I have a depth of 6.25" . Remember these are copies , but of what ? Cluseau is drunk, we better use Sherlock ..... Maybe not... Tuesday is his poker and opium night. Sorry fella , we better use Watson. A bit of a drip ,but he's seldom wrong :D
Is there some calc we can do ?
Rich

4313B
09-18-2007, 04:27 PM
The "2311's" that I have on hand:

Total depth = 4-5/8"
Throat diameter = 1-15/16"

The "2307's" that I have on hand:

Total depth = 8-9/16"
Depth from top of mouth to 1-1/2" diameter = 6-5/16"
Depth from top of mouth to 2" diameter = 4-1/4"
Throat diameter = 1"

I'm not sure either are genuine JBL. The 2311 especially has non-uniform thickness around the horn mouth.

Ian Mackenzie
09-18-2007, 04:35 PM
I'll pull my 2307's out tonight and measure them, they are original JBL as far as I know.

Ian:)

subwoof
09-18-2007, 04:47 PM
Well it looks like my 2313's are made from the image clones if Earl's observation is correct.... And the paint finish was so spot-on like the JBL's. I feel like I just found lead in my batman teething toy....chinese infiltrators...

Never mind sherlock ( but the opium sounds good ) We need hong kong Phooey.

Crap. Well it was a good effort none the less and maybe it's guillotine time for the gray boys in the box this weekend.....let them eat lens.

My measurement was with a ruler that was 1/8 thick so a paper thin business card would go that extra little bit and measure what rich did. So it looks like the 1974 and the 2000 versions of the 2307 ARE the same.

If we knew the formula, any diameter at any length from the throat could be determined. but since the 2307 and 2311 *were* pretty close, and the 2313 *does* measure the same as the clones, it looks like we have solved the mystery.

JUST to be safe, don't cut until the weekend when I get a chance to measure the actual H91's.

And then I will modify my measurements...again....and post the process, AGAIN.

BTW - back in the late 70's I worked for a dealer that had a spray paint can of JBL gray from JBL to touch up those horn cluster jobs.. Has anybody duped it?

sub

grumpy
09-18-2007, 04:59 PM
Nor do I think was Greg. :)

did math to run exponential horns. flares for 2307/2311 are close enough for me;
blame my modeling for the small difference.

Also shown are a modeled 2307 "cut" to 2311 length (makes for a 2" throat)
and the cut needed to achieve a 1.5" throat (a bit over 6" long)

m=.41 would be sub's version.

(NOT INTENDED AS A PRECISE CUTTING CHART)

subwoof
09-18-2007, 06:26 PM
Nice work grumpy. I feel relieved although I now have a pair of one-of-a-kind bastard children. The horn's slightly increased rate probably means it has a wider dispersion at crossover which is probably an advantage when using 10" or larger LM cones.

SO for anybody so interested, I will make the one-time offer of a pair of these "2313" horns and a pair of JBL 2450J's with meyer 1.5" snout adapters ( which will add the requisite 1 inch or so of depth ) for a measly 600 dollars + actual shipping. And we can ship all over the world with no problem.

this is a bargain fella's...

This gives you 434X owners / DIY'ers a chance to play large diaphram without a boatload of engineering and save 2000 dollars...! the driver is a 2" AND 1.5 with adapter!

This offer expires in 24 hours...:)

here is a picture:

richluvsound
09-19-2007, 12:48 AM
I'll pull my 2307's out tonight and measure them, they are original JBL as far as I know.

Ian:)
Ian, in the back door again. Sweet revenge:D

I have the same measurement as Giskard for the 2307's:applaud:

Rich

4313B
09-19-2007, 08:08 AM
Ian let me know just how dissatisfied people are with me and how he got real sick of hearing about it during his visit.

So are these 2307's you have the genuine JBL 2307's I sent you or are they clones?

Earl K
09-19-2007, 09:17 AM
The "2311's" that I have on hand:

Total depth = 4-5/8"
Throat diameter = 1-15/16"

My "stickered" 2311s' have the same dimensions :

They shipped in a bunch of new, "unloaded" Audio Analyst stage-monitors that I purchased, way back in 1980 .

:)

4313B
09-19-2007, 09:22 AM
The foilcals that are on these 2311's I have look like they were removed and re-glued at least once, they are pretty crinkled, so I wasn't sure. Thanks for the data Earl.

richluvsound
09-19-2007, 09:28 AM
Ian let me know just how dissatisfied people are with me and how he got real sick of hearing about it during his visit.

So are these 2307's you have the genuine JBL 2307's I sent you or are they clones?

Giskard,

is this question directed at me ?

Rich.

subwoof
09-19-2007, 09:28 AM
All 4 of my 2307's concur with the previous measurements.

So it's off to the machinist to have some aluminum flanges made and this time it's weld weld baby.

If I can get a price break I might have a dozen made - anyone so interested, let me know soon..:)

sub

richluvsound
09-19-2007, 09:50 AM
All 4 of my 2307's concur with the previous measurements.

So it's off to the machinist to have some aluminum flanges made and this time it's weld weld baby.

If I can get a price break I might have a dozen made - anyone so interested, let me know soon..:)

sub

Hey Sub,

what filler rod are you going to use . I just going to tack weld and then DEVCON fill the devils. I would'nt like to weld all of it unless the filler and work piece match.

rich

4313B
09-19-2007, 09:51 AM
Giskard,

is this question directed at me ?

Rich.Yes.

subwoof
09-19-2007, 10:06 AM
There is a local company that does some serious AL welding so it would be a continous weld not a few tacks. Weight isn't an issue with the Nd's but someone else later might want to use the 2447 since they will be dropping like a stone in price....

I have 2 straight days of Dr visits and traveling for the wife but all the med stuff will FINALLY be over. It's been almost a year since the diagnosis....:)

I will draw up the flange tonight and post if I can also get my teenage daughter to NOT ask for multiple "taxi" trips....

sub

richluvsound
09-19-2007, 10:18 AM
Giskard,

the horns you sent me came in a box marked 2307. They are a non -crinkel black. I have no reason to doubt your integrity.

I have a pair that Guido sent me that are copies . These are the ones I wish to mod for my 2435's.

As far as gossip is concerned...... I have been waiting to for some parts to complete a project for another member . This has been a topic of conversation. It has been frustrating ,but not to the point of bad mouthing you.

I understand you have had some big changes in your personal life and have tempered my comments with this in mind.

From what I understand , there are indeed people pissed off, but NOT ME !!!

I don't care enough to give my energy to negativity. I don't know you. All I know is that you are a very talented man and that peolpe here on the forum respect and depend on you.

I don't not wish to get drawn into anything Toxic.

You don't know me Giskard. If you have pissed me off I would PM you as I did before ( remember )


I should of PM'd this but , as you chose to bring this into the thread , I feel this is the best place to give my response

Rich:blink:

richluvsound
09-19-2007, 10:22 AM
Sub,

best wishes for the coming days.

Rich

4313B
09-19-2007, 10:49 AM
all the med stuff will FINALLY be over.
That's good news subwoof! :yes:


Giskard,

the horns you sent me came in a box marked 2307. They are a non -crinkel black. I have no reason to doubt your integrity.

I have a pair that Guido sent me that are copies . These are the ones I wish to mod for my 2435's.I just wondered what horns you were measuring. The two old grey 2307's I have no longer have the foilcals. It seems we are all in agreement with the dimensions at least so that's a relief.
As far as gossip is concerned...... I have been waiting to for some parts to complete a project for another member . This has been a topic of conversation. It has been frustrating ,but not to the point of bad mouthing you.Oh, it isn't gossip, it's a fact that I take longer than some to get this stuff done. I really should have gotten subwoof's horns back to him rather than waiting until I also did his 2435's. He posted that it was two months since he talked to me. It seemed like two weeks to me. Perception. The actual date/time stamps support him though.
I should of PM'd this but , as you chose to bring this into the thread , I feel this is the best place to give my responseI merely noted the obvious to alot a people since I've been catching it from all sides the last couple weeks. I'm late; I know it, you guys all know it, that's all there is to it really. Sorry.

John W
09-19-2007, 11:51 AM
Has anyone actually tried to integrate one of these horns into their 4345/4343, other than just slapping it in and giving a listen?

Ian Mackenzie
09-19-2007, 03:55 PM
Ian, in the back door again. Sweet revenge:D

I have the same measurement as Giskard for the 2307's:applaud:

Rich

Mine were also the same.

Ian

richluvsound
10-11-2007, 05:37 PM
Guido and I disconnected the fog horn and wired up the 2435 with a H9800 horn. I'm thriiled with the results. I'm torn though, It has completely changed the warmth of the 45's. We have started to mod the cc networks( PM Guido for the technical bit) I cant make any final decision until the moded horn is in and the xover fully moded....... I wonder how much of what I'm hearing is the horn and not the 2435.


more to follow.

Rich

4313B
10-11-2007, 06:11 PM
I wonder how much of what I'm hearing is the hornYou shouldn't be able to hear the horn.
As G.T. said "We got rid of that "horn" sound ages ago..." :p

Ian Mackenzie
10-11-2007, 09:07 PM
Rich,

When I heard Bo's updated 4345 with the Tad 2002 I can say it had that 4345 sound/ presentation. But was purer, smoother and had more depth.

Not cold or sterile.

Suggest you get the crossover all sorted before arriving at any conclusions.

Ian

Ian Mackenzie
03-30-2008, 03:38 AM
As some of you are possibly aware I have recently installed the short 1.5 inch horn and the JBL 2435 Be.

I know Mike is interested in some feedback on this idea and I plan to post some details later in the week.

iMac

subwoof
03-30-2008, 06:07 PM
Cool...

I just did the drawings for a local jobber to make and install the aluminum 1.5" flanges on a group of (8) cutdown 2307's.

These will be a different length ( a little longer ) than the "clone" horned 2313's you have but I think your analysis should be relevant either way.

After looking at all my horns that are in the shop, along with the PT's that are enroute from JBL, I think I am going to use the 2332 array 90 degree 1.5" aluminum horn for the 4345 clones I am going to build late this summer and was wondering if you have any of those horns to do a side-by-side analysis and/or network tweaks..

I could send one out forthwith ( love that word ) to keep your schedule fluid.

Mike

Ian Mackenzie
03-30-2008, 07:11 PM
Hi Mike,

I don't.

That would be interesting.

Ian

pos
06-05-2008, 02:20 PM
As some of you are possibly aware I have recently installed the short 1.5 inch horn and the JBL 2435 Be.

I know Mike is interested in some feedback on this idea and I plan to post some details later in the week.

iMac

Hi Ian,
So what are your conclusions regarding this 2435 integration? Is it aquaplassed ?

Ian Mackenzie
06-05-2008, 02:59 PM
I should have some information in the next few weeks.

mini
06-06-2008, 12:19 AM
capable of *significant* advantages in response, distortion, power and of course, weight

Hi,

Did You ever since confirm that the goal has been reached with the DIY adaptors? Concerning distorsion first? My background is a homemade but own comparison EV HP940/DH1a vs JBL 2352/2447. I didn't see to much advantage on the 1.5 side. And it was dm'd LOUD (never ever do that without a sound ear protection, don't even try!).

Best Regards

reVintage
06-06-2008, 03:18 AM
As this old thread came up I got curious and did some calculations on the various combinations based only upon length from phaseplug, throat area and mouth area. I came up to this assuming we have pure expontial flares:

2" driver + horn 300Hz flare, 1kHz Fu
1" driver(guessed throat dia at phaseplug is 3/4") + 2307 350Hz flare, 1kHz Fu
1,5" + cutdown 2307 500Hz flare, 1,4kHz Fu(due to length)

As an exponential horn is made up from a decided throatarea I doubt the cutdown 2307 is to be considered as an expontential, so those figures are maybe not valid.

Anyone who have made any calculations pointing in the same direction as mine?

pos
07-23-2008, 06:08 AM
I should have some information in the next few weeks.

Hi Ian,
I see that you are now exploring other options (http://audioheritage.org/vbulletin/showthread.php?t=21660), so what were your conclusions on the 2435/4345 integration?

Ian Mackenzie
07-23-2008, 06:47 AM
It came down to the prospect of having to redesign the network and the effort of carving into my nice baffles.

The 2435 is not a user friendly driver to use for diy people.

For the moment I have put it on hold in favour of redesigning the entire front baffle of the 4345 to complement proper integtration of the md cone and protential horn /driver candidates.

That of course will mean a new network, most likely active.

Suggets you look out the a Tad 2001 or the more recent tad model for stock 4345 updates


Ian