Best JBL mod for Klipschorn?

[xvtwin]

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.

Thanks!

[Maron Horonzakz]

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.

[Robh3606]

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.

http://www.lansingheritage.org/html/jbl/jbl.htm


http://www.jblpro.com/pages/obsolete.htm

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????

Rob

[xvtwin]

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!

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.

[GordonW]

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...

Regards,
Gordon.

[Mr. Widget]

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.

Widget

[Earl K]

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]

Here's a profile of the same horn & driver .

[Maron Horonzakz]

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]

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]

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.

Widget

[Robh3606]

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.

Rob

[Mr. Widget]

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.

Widget

[Robh3606]

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??

http://www.jblproservice.com/pdf/Ven.../VS3115-WH.pdf


Rob

[Mr. Widget]

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.

Widget