View Full Version : Best JBL mod for Klipschorn?

11-09-2004, 03:14 PM
I'm considering some modifications for my Klipschorns (1990, AK-3) in an attempt to smooth out the upper midrange. This is my first post here so I hope I'm in the right place. I've read a few opinions about this so I thought I'd share them and see what some of the veteran JBL people think. My power amp is a Golden Tube Audio SE 40 that has been modded by Sonic Craft.

One individual (from the Klipsch board) replaced the top end with 2447 driver/2354 horn with a JBL Pro Dsc 260 active crossover and biamp. It is now a 2 way. About $3000. Can this combination provide good HF response? Seems like that is a lot to ask of the 2447. He says it works for him.

Another (less ambitious) suggestion is to replace the midrange driver with a 2426h and use a dbx Drive Rack PA as an active crossover/biamp. This was from a local dealer. They were helpful but I don't think that they have tried this before. Would a 2370 horn be a possibility?

Another very ambitious project comes from the Audio Engineering League. They have a few different suggestions. They seem to like the 2404h tweeter and use it with either JBL 2123 or 2012 direct radiators. They also use an older Altec horn in one of thier applications. Very impressive web sight.

I'm quite impressed (and confused) by the sheer number of JBL drivers and horns. Any suggestions (other than I should have bought JBL in the first place) are appreciated. I'm just trying to make my speakers sound better.


Maron Horonzakz
11-09-2004, 06:25 PM
The klipsch modifications ive done are ...2450 with 2397 Smith wood horn & 2404 tweeter on top. the K33e woofer is hard to beat but JBL early 2205 with 4 pleats & not the later2205 w 2225 cones or JBl E 145 works fine . all to be tri amped with class A amps. TAD drivers 4001 work fine too w TAD 703 super tweets. 2123 10" 2 each side for mid work fine I prefer 2250 8" 2 per side. Pick your mid flaver. Still 2404 on top. Or fostex 900 super tweets. Ive spent 20 yrs on findings what woofers dont work compliance & TS peremiters all wrong.etc etc.

11-09-2004, 06:51 PM
Hmm Where to begin??? I have never heard K Horns so I am not all that familliar with them. JBL is what I am well versed in so maybe I can help you through all the different horns/drivers. A basic primer is 242X is a small format 1" driver the 244X and 245 are the large format drivers. The horns are all over the block. There are families like the Flat Front Biradials 2370/2380/82/85 Biradial 2344/2342 and the older Radial horns like the 2345 and so on and on and on!! The best thing to do is just go to the Vintage page at the Pro site and look through the catalogs here.



What to do???

Well is the midrange horn the problem?? If so what is the lower crossover frequency and the upper??

2370 might work depending on what the lower crossover point is lowest reccomended is 630Hz. The large format horns like a 2380 is 500Hz

Does JBL/Altec/Selenuim have a drop in replacement that will improve performance and fit without modifying the enclosure??

Do you want a drop in or are you planning some real changes??

Once you get beyond this and start adding 10" midranges as an example you are really designing a speaker from scratch.

Just how far do you want to go?? You can't modify the K without them loosing resale so????


11-10-2004, 07:58 AM
Sorry, guys. I probably should have posted this to the "off topic" area. I'm learning my way around here.

I did'nt realize that I would have so many options. What also complicates matters is that I have not actually heard any of these mods. A good point was made about resale; I think that I would rather (at least initially) just "drop in" for now. 2404's on top to replace the T35 would be easy and is a definite possibility although that is not addressing the midrange problem.

Crossover points are 400hz and 6000hz.

A possible solution would be to replace the midrange driver with the 2426 and keep the existing horn: I think some type of adaptor would be needed. I also realize that the horn could very likely be the problem. Another possibility would be to have a replacement enclosure made to house a different horn with the 2404. I guess that would make it a "new" speaker.

I have to laugh at myself about considering these mods; I'M NO SPEAKER DESIGNER! :D

I love/hate my Klipschorns. They absolutely rock the house and are very exciting to listen to for rock/pop (especially concerts on DVD). Drums sound like DRUMS! Conversely, female vocals, especially women who have higher pitched voices, can be painful. That's why I'm here.

And while I'm rambling, can anyone recommend a good source for new/used JBL equipment (besides Ebay)? I'm finding out that it's not inexpensive.

Thanks for all comments.

11-10-2004, 10:32 AM
My suggestion? Well, it may not be the most "cosmetically friendly"... but to maintain a similar-to-stock crossover point, I'd use either the JBL 2440/2441/2445 driver, or an Altec 802 or its ilk, on a 500 Hz horn such as an Altec 511, JBL 2380/2382 or something similar in bandwidth. Then, either a 2404, 2405, or (if you're looking for something more economical) the Fostex FT17H horn on highs. I'd prefer the 2404, since they have a wider dispersion area.

Build a stand/enclosure for the horn/tweeter, to sit on top of the K-horn... simply just disconnect the factory mid/tweeter drivers inside, and leave them bolted in. That way, you can easily restore the system to stock later, if desired...

With an Altec 802/511 horn and a 2404H, you could, at least in theory, probably use the factory crossover. I'd increase the crossover points, to 500 Hz and 8000 Hz, if it were my system... something like the Altec 500 Hz crossover or JBL N500, and a JBL N8000 or equivalent, should get in the ballpark.

Heck, now that I think about it... any reason he couldn't use a Hartsfield crossover network? Some of the later ones were three-ways, right?

Yeah, this plan is rather elaborate... but it would have the benefit of being completely "modular"... ie, there'd be no permanent effect on the K-horns...


Mr. Widget
11-10-2004, 11:29 AM
I think that I would rather (at least initially) just "drop in" for now. 2404's on top to replace the T35 would be easy and is a definite possibility although that is not addressing the midrange problem.

This is not a bad idea. The T35A used in the Klipschorn is a bit harsh and I bet it is part of your issue with female vocalists.

A possible solution would be to replace the midrange driver with the 2426 and keep the existing horn...
The 2426 comes with a removable snout that when removed will screw directly on to your K400 horn. The problem is the low end. You would need to get a pair of 2470 phenolic diaphragms for these drivers. Alternatively you could use 2470 drivers, but then you would need adapters and they will degrade performance.

To really improve the midrange you will need to replace the horn and driver. Gordon's suggestion of using an Altec 511 is on the right track but you really need to use a horn that can go down to 400Hz. The K400 is optimistic in achieving 400Hz and even the selection of 400Hz is pushing it. Since the Klipschorn bass horn is so folded it would be much better with a 300Hz crossover. Short of a GIANT JBL 2356 with a 2482 I am not sure what you can use for an actual improvement. The JBL 2397 and the TAD horns that I really like is not good solutions since they do not have the low end response.

Here is forum member Al Klappenberge's upgrade for his Belle Klipsches. http://www.toad.net/~alk/belle8.html

Since their bass horn has less folds it is still listenable with a much higher crossover frequency, however it too would be better with a larger mid horn and lower crossover point like that used in the LaScala.

I hope this helps.:)


Earl K
11-10-2004, 12:40 PM
I've heard on the net for years that the pinnacle of K-Horn sound was achieved by using British-made "VitaVox" components. This makes sense to me , since these licensed Cdn versions were assembled away from the direct influence of the companies creator. This freedom, gave a freer hand in the interpretation of how to make a decent sounding K-Horn. From my readings , Mr. Klipsch was (almost to distraction) more interested in sustaining the reputation of his corner "concept" with the end result being the exclusion of better sounding components. Using well engineered devices such as Altec or JBL would have just detracted from the hard-won reputation that was embodied in his folded-horn patent. This particular focus led to a pretty "shortlist" of components that were considered "good-enough" but having "little" or no name-recognition of their own.

So, if I had a K-Horn that I wanted to update instead of selling , I'd be looking to recreate the VitaVox ( Canadian ) version. That means investing $1500 to $3500.00 for all the used VitaVox parts. Yes, I'd add a tweeter , such as the 2404 JBL.

VitaVox Components are:
Drivers are S-2 ( 3" diaphragms )
Horn is ??? CN191 ??? or Dukane 5A 300
Woofer , I believe is the AK-154

Failing to get these fairly rare parts would lead me consider the Altec 291-16a as the driver mated to an Altec 311-90 horn. I'd have to listen to that stock woofer before deciding to swap it out for something else . This aluminum diaphragmed Altec has a "Kapton" (plastic) suspension that allows a lower crossover point than the typical 288 model. If I couldn't get 291(s) I'd consider phenolic diaphragmed 290s or 292(s).

If I had to give up on Altec parts for whatever reason, I'd procure ( cheap ) JBL 2482 drivers ( 4" phenolic diaphragms ). If these were perceived to be too rough sounding ( even after all the crossover tweaks known to me ) I'd install Radians' replacement aluminum diaphragm ( # 1282 - I'm not sure if it's still available ). This diaphragm essentially turns the 2482 into a bigger diaphragmed version of the 3" Altec 291 - both having a very similar suspension . Getting a good sounding radial horn for this JBL would be a bit of a trick. It would likely need to be custom built. Good thing there are guys around who will do this .

Here's a picture of the VitaVox horn with S2 driver .

regards <> Earl K

Earl K
11-10-2004, 12:42 PM
Here's a profile of the same horn & driver .

Maron Horonzakz
11-10-2004, 12:47 PM
You can use the TAD drivers down to 500hz with ease. They are very efficient in a klipsch & your probably not ever going to crest more than 2 watts. A new mid grill and horn unit behind existing grill is easily made. You wont even notice the difference. the old grill & frame can be stored away for later use to return to origional use. No one I know has ever had any trouble crossing over TAD or JBL drivers at 500 or even 400 at these low power levels The horn cut offs or alot lower than publihed K-401 is 270hz others the same way 2397 about 300hz. Vitavox components would be ideal. But try to find the drivers & horns near impossible. And that Vitavox woofer a rare one indeed. the compliance has to be just right. this i know from expierence. Also the Vitavox bass bin was made of 3/4 inch birtch & not the 1/2" of the klipsch bass bin. Ide like to try the sonoglass JBL K2 radial horn in that mid slot. Now if I could just borrow the one from the MAY PROJECT I wonder if I could intercept that shipment & high jack those horns. They could never find me for months up in the nortern tundra of NE MO.

Earl K
11-10-2004, 12:48 PM
And a pair of said horns.

You can see the classic "Radial" profile from these pics.

What makes these horns special - are the 3 "vanes" in the inner bell .

The pictured pair of horns are likely later versions. They are actually 2 halves bolted together at the perimeters. They also lack the "damping" mats of the horns pictured above.

These VitaVox horns predate TADs "vaned" wonders by decades while they were ( somewhat ) contemporaries of the JBL 2397 "Smith-type" diffraction horn .

Mr. Widget
11-10-2004, 04:25 PM
No one I know has ever had any trouble crossing over TAD or JBL drivers at 500 or even 400 at these low power levels The horn cut offs or alot lower than publihed K-401 is 270hz others the same way 2397 about 300hz.
I agree that you could use most of the JBL or TAD drivers at these low frequencies, but you would need to be cautious about power levels. Certainly in a sane home system a watt or two will be quite loud and all that is required.

As for cut off frequency, the general rule of thumb is to have at least an octave between horn cut off frequency and the crossover frequency. Therefore a horn with a cut off of 270Hz is really pushing it in a system crossed over at 400Hz. I realize Klipsch does this, but the point here is to improve upon the system. I have also heard of people using 2397 horns on their Klipschorns and have been satisfied with them, but at that point there are also many thousands of satisfied stock Klipschorn owners too.

If I were to try to improve upon the design I would get a larger mid horn cross over at a lower frequency and use superior drivers. Vitavox are certainly nice, but so are JBL and TAD.


11-10-2004, 05:07 PM
After seeing where the lowest crossover is I can understand why they were dropping in 10" drivers. Makes perfect sense. The 10 will do a much better job than a compromissed horn where you are really pushing the lower loading limits. None of the stock JBL horns will get you down to 300/400 hz. 2123's do sound nice.


Mr. Widget
11-10-2004, 05:19 PM
None of the stock JBL horns will get you down to 300/400 hz.

The 2356 will. It has a very narrow horizontal dispersion, but in a corner placed speaker that is probably OK. Unfortunately it is rather large... especially its depth.

2123's do sound nice.

Sure but it is less efficient and unless you build a big mid bass horn for it, not a bad idea BTW, you no longer have a fully horn loaded system.


11-10-2004, 05:54 PM
Widget your right but if you are biamping it you can get away with it. What are K horns 104db?? 2123 is 101 so 2 for 104. I guess The idea is to get away from a large midrange horn, How about the 3115 horn??? With the M209-8?? Could you clone it?? Hey Mike B where are you??



Mr. Widget
11-10-2004, 06:10 PM
2123 is 101 so 2 for 104. I guess The 2123 is 101dB watt in the midband. It sure isn't anywhere near that at 300Hz.

How about the 3115 horn??? With the M209-8?? Could you clone it?? Not for less than JBL's price.


Alex Lancaster
11-10-2004, 06:39 PM
:) Its getting to the point of selling the horrible Ks, and getting some real JBLs.

11-10-2004, 07:07 PM
Very impressive, fellas!!!

Thanks very much for commenting on the many options available to me. I can see that I need to educate myself about the various JBL and Altec products available. I've never heard of Vitavox. Very interesting that there was a Canadian version of the K-horn; I've never seen one for sale or even heard of one. I have looked at the Pioneer/TAD websight. Pricey. There is a company close to where I live that sells reproductions of classic horn speakers that uses TAD drivers. I think I need to drive down there and take a listen.

It wasn't until after I bought and spent time with my K-horns that I realized there was such a big wide world of horn loaded speakers out there. My impression of JBL was made when I was in high school in the 70's. A friend's father had a pair of bookshelf speakers that we used to crank up when he would leave the house. The grills had raised blocks of brown speaker foam.
I was impressed! I don't think his dad would have been.

Thanks again for the comments. I'm going to enjoy this sight. Aren't these fun toys?

Don McRitchie
11-10-2004, 07:24 PM
The grills had raised blocks of brown speaker foam.
Curtain call for Bo. Curtain goes up in five minutes.

scott fitlin
11-10-2004, 07:32 PM
Curtain call for Bo. Curtain goes up in five minutes.:rotfl:

Saturday Night Live here we come!

11-10-2004, 08:33 PM
One idea that came to mind, was to use something like a 2123 in a "Perkins-style" horn... like a miniature JBL 4560, for a 10". That'd load, easily, down to 300 Hz. And the lower end gain would be enough, probably,to mate with the K-horn bass.

Remember, with a three-way setup, the "midband gain" both in the crossover, and due to the fact that the woofer and tweeter overlap the mid, the midrange can be up to 2-3 dB LESS efficient than EITHER the woofer or tweeter. So, 100dB sensitivity @ 300-400 Hz, should do the trick. I'd think, with the horn gain "propping up" the bottom of the 2123, it probably would do the trick.

Though, if you're talking horn-loaded 2123, I'd probably be inclined to make it a FOUR way... with say, a 2420/2421/2425/2426 on either a Smith horn or something like a 2370 for the upper mids, and a 2404 or 2405 for VHF. I'd be inclined to bi-amp this setup... run the K-horn bass on one amp, and the remainder of the drivers (2123, 2425, 2404, or whatever combo is picked) on a second amp, bi-amping the setup at about 350 Hz or so. I'd bet THAT would be SERIOUSLY impressive...

In lieu of that, the idea of an Altec 311 is probably the most practical functionally, if not from an aesthetic or space-friendly standpoint. That, and a 2404 up top, would probably be extremely impressive.


Maron Horonzakz
11-11-2004, 06:34 AM
Two 2123 per side raises the gain sensivity to 104 db & 2404 is already at 105db so level matching is almost perfect. Community drivers make a good match also on certin horns But the Vitavox Klipschorn was the Roll Royce of that line.

11-11-2004, 05:15 PM
The grills had raised blocks of brown speaker foam.
I was impressed! I don't think his dad would have been. Me neither... :rotfl:

Go hear (sic) where the mystical grills are discussed - http://audioheritage.csdco.com/vbulletin/showthread.php?p=6323#post6323
we had some fun there...

And the legendary cabinets you lust for are the L100's - they receive exhorbitant amounts of attention here. Hell, maybe I shouldn't hate 'em. Most of us are here because of them - once we heard them we knew JBL could do better... :eek:

xvtwin = the Yamaha? Nice bike, dood... :yes:

11-11-2004, 07:34 PM
Honda VTX 1800....thanks anyway!

I must confess. This is how our "critical" listening went on the L100. Dad pulls out of the driveway, shots of tequila come out (subsequent SCREAM), LP gets fired up and on goes AC/DC, Led Zeppelin, or Tommy Bolin (Tommy Bolin? You could FEEL the bass string vibrate on "Post Toastie"-I have'nt heard it since then but I think I need to find it NOW!). Who's on the lookout? Maybe another shot of tequila. Or could it have been that Pioneer 270 WATT! YES, 270 WATT receiver that made them sound so good? Certainly left an impression on me.

I'm learning here. I purchased a pair of 2404H tweets. Should have them next week. Gotta start somewhere. Should be fun.

11-11-2004, 07:38 PM
"I purchased a pair of 2404H tweets. Should have them next week. Gotta start somewhere. Should be fun."

Welcome to the "nut" house:D


11-11-2004, 07:39 PM
Maybe another shot of tequila. I think - I think I love you! Kiss me!!! :eek:

Seriously - you would LOVE my band... :rotfl:


Sorry to have guessed the wrong bike - not being a bike-guy, I got as close as could be expected (hell - I was lucky to have guessed it was a bike! There's other motorheads here - maybe they'll get in touch [hey, Andre...?]).

Oh, and you being a tequila fan, the engineer for the band I lead sing in, recently turned us onto "Cabo Wabo Blanco". Whoa... Sammy Hagar knows plenty about tequila, huh? Freeze the stuff - it's unbelievable (says he, a fan of Cuervo Gold...)

Maron Horonzakz
11-12-2004, 11:29 AM
Now that I,ve got everybody,s attention!!!!!! I dont believe the JBL beryllium drivers are a improvement . But are a compromise. I dont make this statement lightly.

Mr. Widget
11-12-2004, 11:36 AM
Could you elaborate?


Maron Horonzakz
11-12-2004, 06:03 PM
Elaborate?......Think about it. What other companys use Be diaphrams. Why are the JBL units so different? And why did they choose to form their diaphrams that way? Also why the Aquaplas? Eliminate the coating and what do you find? Befor you answere think this through. Substitute the K2 S98000 mid driver with what superior driver ? Then throw away the 045Be tweeter.

Mr. Widget
11-12-2004, 06:08 PM
What are you talking about?

scott fitlin
11-12-2004, 06:11 PM
They tell me that JBL hot rolls their Be, while TAD still does it the old way, sputtering, or vacuum depositing as its technically known!

I guess they aquaplas them to smooth out the response, but if you do remove the coating, what would you find?

As far as professional grade drivers, the only other company I know of that uses Be is TAD. And Focal is making high frequency units for consumer speakers using Be diaphragms.

What else do you have to add Maron, I would like to know more!

Maron Horonzakz
11-12-2004, 06:32 PM
If the Be is manufactured properly You dont have to butter up the surface to smooth out the spikes. the 435Be could have been better flat out to 20k easily. And that ineficient 045Be what were they thinking? And they had to butter that one too. There was a better tweeter (Be) with out slathering aquacrap on it. Sidney Harmon is asleep He could have probably bought the other speaker co. And the drivers could have come out of that superior manufacturing process.

Mr. Widget
11-12-2004, 08:22 PM
...the 435Be could have been better flat out to 20k easily. And that ineficient 045Be what were they thinking?

OK, I see where you are going with this.

I am not sure that the 435Be could have been made to go "flat out to 20k" since neither of the two TAD units I have (4001 and 4003) "go flat out to 20k" and they both have significantly more powerful magnets and no aqua-butter. They do have greater HF extension than the 435Be, but I believe that the "lack" of HF extension for the 435Be and lower sensitivity of the 045Be are due to engineering compromises that were accepted since these drivers were purpose built for a specific system and were not compromises within the scope of that system. These drivers were not built to be stand alone drivers but rather to enable JBL to assemble a truly spectacular system called the K2-S9800.

As to why the aqua-butter? Hell I don't know. I guess they feel it helps. They are using aluminum in the 435AL in their down market design. It would be interesting to compare the response and sound quality of the two diaphragms.


Mr. Widget
11-12-2004, 08:27 PM
Sidney Harmon is asleep He could have probably bought the other speaker co. And the drivers could have come out of that superior manufacturing process.
Maybe. The retail price of the K2-S9800 is already beyond most people's threshold of pain. I assume you are referring to TAD. The cost of producing the TAD compression drivers is so high that using them in the JBL flagship would probably double it's price. I am not sure that it would be that much better.


Maron Horonzakz
11-14-2004, 11:28 AM
And on that comment...B N Locanthi is smiling down on you.

11-24-2004, 07:01 AM

The Klipsch corner horn bass section exhibits irregular response above say, 300 Hz. [1]
For best performance, a muscular compression driver such as the JBL 2490H [2] will get the job done at the needed lower crossover frequency. To do this a reentrant mid range horn would have to be designed and built. A similar approach was used by Roy R. Carlson in his design of the EV Patrician IV [3]. Here a pair of 828HF Drivers with A8419 Horn segments radiated into the back of a wooden mid-range horn to cover frequencies between 200 and 600 Hz. The JBL driver recommended will allow an upper c/o of 1000 Hz or better if needed. Just keep horn fold width less than wavelength on the highest frequency to be passed.



[1] Title: A Revised Low-Frequency Horn of Small Dimensions
Publication: AES-J, Vol. 48, No. 10, Pg. 922 (Oct-2000)
Author: Roy Delgado, Jr.
Author: Paul W. Klipsch
Abstract: A widely used commercial loudspeaker system, originally described in 1941, has been modified and improved. The modern version of this system claims smoother response in the pass band region, reduced distortion, and an increase in its upper frequency limit. These and other improvements have been installed in a cabinet, which occupies the same footprint as that of the original design.

[2] JBL 2490H Mid-Range Compression Driver

Note that this drivers flat PWT (power) response below 500 Hz becomes displacement limited at its lower frequency limit. For at home listening, this should not present a problem so long as reasonable horn loading is maintained an octave below the lower crossover frequency used. Also a high pass filter slope of no less than 24 db/octave will provide additional protection for the driver. If an electronic crossover is used, be sure to insert a large D.C. blocking and small bypass capacitors in series with the driver voice coil.

[3] Electro Voice Patrician IV and Component Drivers http://www.hifilit.com/hifilit/Electro-Voice/117-17.jpg

Maron Horonzakz
11-24-2004, 07:21 AM
The AES paper on the new bass horn (Delgato/Klipsch) Is the still born Jubilee two way Klipsch Horn good up to 800hz. And the bottom end is 6db better at 35hz. A pro cinema version is in the works.

11-26-2004, 11:17 AM

This stage system has been around for about two years.




Maron Horonzakz
11-26-2004, 11:36 AM
Yes the KPT uses 2 12" woofers.... Another version is being talked about using 2 15" woofers.

01-01-2005, 11:03 AM
The stock klipsch Mid horn and driver and possibly the crossover are a very nasty combo indeed. We have side by side compared these to several other combo's and the klipsch always sounds very bad when compared. My buddy doesn't even listen to his since he got his new setup. Now the K horns are sitttng upstair unused. I never did like them much. I have heard many other horns that work much better the Klipsch driver.

Speaking of Vitavox, I have a pair of the corner cabinets. I don't have any Vitavox drivers though. I am using Beyma woofer in them and have had Altec 416b's in them as well. They are a much better cab than the K horn cab. Mine have full sides ( waveguides ) on them so corner placement is less critical.

I live in the city where Vitavox Canada was located. We recently met the original draftman who drew up the Vitavox Cabinets. He was quite surprised to see a pair so many years later. We actualy have his blue print in full scale and they are huge drawing to say the least


Jim DiFalco
01-01-2005, 11:25 PM
Vitavox components:


Ron K
03-04-2005, 10:27 AM
HiAll. I have built many corner horn systems. My favorite ones always had a midbass horn with K110 or E110 or 2123 driver. I have tried most of the 1" Jbl and Altec horns on these systems. Sometimes with tweeters. Lot of fun and some incredible results. My current favorite is my rear loading corner horns with 2226 drivers. Good performance to 25 Hz, And allows time alignment with mid and high. Just my .025 Ron

Earl K
03-05-2005, 11:01 AM
Okay, I'll try to keep this relevant to JBL models' ( Current & from the Past )

- Here's a possible mod. that might allow a K-Horn to run 2way and still use a crossover point down at 300 hz .

- The parts used were RCA MI-9594 Horn (with MI-9191 entry Throat) & a B&C 900 nd driver ( 3" Ti diaphragm, 1.5" exit ). This horn has a 60x40 pattern ( it's obviously a radial design horn ).

- You can see that this horn easily loads to 300hz ( my electronic crossover was set to @ 290 hz ). This driver ( like most modern "fast-exit" drivers ) has a "highish" recommended Xover point (of no lower than 800 hz) . ( Oh Well :dont-know )

- Hopefully JBLs' new 2431h driver would holdup just as well ,when working in this lower octave ( on a huge horn ) / ( just for HiFi use ) . See Zilch for his developing 2431h information .

- A comparable horn to this RCA9594 is JBLs' old 2356 ( The one Widget mentioned ) .


Earl K
03-05-2005, 11:10 AM
A Few More Pics

- these pink-noise FR displays show the effects when the CD horn boost is engaged .

- I've only listened to this setup with pink-noise. But I somewhat feel that I would forego the CD horn boost.

- I may listen to this sometime to gauge the midrange loading effects on this poor diaphragm, which is ( just about ) completely relying on horn loading for the response seen below the recommended crossover point (800hz) .

- It's hard to see, but the 6 db down point was at around 300 hz , just like it should be with this LR type ( 24db/octave crossover ) .

- Moving the crossover point lower revealed that - well - that was it,,, this diaphragm could do very little more . This diaphragm is also enclosed in a "tight" backshell ( small volume ) - just like JBLs' newer pro series compression drivers :D