Crossover tweaking for new JBL horn system

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03-26-2005, 11:44 AM
jlharden

Crossover tweaking for new JBL horn system

Hello!

I'm looking for some crossover advice from the experts here at Lansing Heritage board. I've assembled a little 4-way JBL system. It uses a pair of 2226J's loaded in 4648A cabs for the bass. These cover approx. 200 hz down and are crossed electronically at 12 db/octave and biamped. Covering 200-1.6K is a 2123J midrange loaded in a conical horn. Midrange uses a single inductor and hands off to a 2426J in 2370A horn. The 2370 rolls off naturally on the top where I've sumplemented them with a 2404H tweeter. Both the 2426J and 2404H use 3rd order slopes with the crossover points at 1.6K and 6K. The 2426/2370 is padded 4 db to match the horn loaded 2123J and 2404H tweeter. Sonically everything appears to be working quite well for the first attempt at crossover points and padding. The only troubled area is the 2426/2404 crossover point which I assumed would be the least troublesome. It seems I've got a decent amount of driver summing at the 6K crossover point. I may try something a little higher to smooth the transistion. I've searched the archived but haven't been able to find information where anyone has attempted a using a 2426/2370/2404 together. I'm using the 2404 to eliminate the need for a passive rc network on the 2426/2370 because I wish to keep sensitivity as high as possible(will be powering with SET's). Would appreciate any thoughts or advice. Obviously it's a try it and see type thing and I'm very close, but thought I'd check to see if anyone had attempted what I'm doing so I could draw a little experience and apply it to my project. Will post some pictures as soon as I'm able to load camera sofware into new computer(new computer on order!). Thanks in advance! Jerrod
03-26-2005, 02:16 PM
Zilch

2370A/2426 don't roll nowhere until 16 kHz.

http://www.jblpro.com/pages/pub/components/2370a.pdf
03-27-2005, 02:13 AM
pangea

2426/2404

I got a tip many years ago, from the Swedish JBL rep.
It sounds awkward I know, but it works great.
I have used it in quit a few settings, as well as on a 2425J/2370 and 2402 combo.

Although the tip originally was intended for a 2445J/2402 set-up, which has a mor pronounced "hump", it also works just as well with the 2425J.

I use for the 2425 only a 12dB/oct. BW Hi-pass filter from around 800HZ and for the 2402 I use only a 1uF polypropylene cap in series, which gives a 20kHz x-over point which falls with 6dB/oct. downwards. Not only will the transition be smoth towards the 2425, but your 2404 will sound as best it possibly can.
This trick will also extend the frequency range, as it "shaves off" the "hump" of the 2402.

If you can time-align the 2404/2426 combo as well, the result will be superb!!!

BR
Roland
03-27-2005, 07:51 AM
HenryW

I am not sure how much help I can be here, but after listening to my new speaker config for about 5 hours yesterday I can attest to my ear being very pleased with a 2425/2370 with a 2404 where the transition is at 7500 hz. So my shade tree fix it manual says to try for a higher transition point....
03-27-2005, 08:23 AM
pangea

Quote:

Originally Posted by HenryW

I am not sure how much help I can be here, but after listening to my new speaker config for about 5 hours yesterday I can attest to my ear being very pleased with a 2425/2370 with a 2404 where the transition is at 7500 hz. So my shade tree fix it manual says to try for a higher transition point....

I'm sure it would sound even better if you x-over a bit higher.
I my self would never go below 8k under any circumstances. I prefer 9 or 10k even.

IME, whenever people have anything negative to say about the JBL ring-radiator, it's "honky" or whatever, they mostly have chosen a too low x-over point, and/or have used cheap amps or suboptimal components in their x-over.
Unless the 2404 behaves totally different than the 2402, their "weak points" should be similar.

BR
Roland
03-29-2005, 02:45 PM
jlharden

Hello!

Thank you for the replies. Pangea, I tried the first order 20K crossover point and it worked wonderfully. Just the type of idea I was after. I was stuck on using a third order network and couldn't see the most simple solution. I'm currently using a very cheap cap, but will soon replace with a more permanent part. Thanks again! Jerrod
03-29-2005, 02:52 PM
pangea

Quote:

Originally Posted by jlharden

Hello!

Thank you for the replies. Pangea, I tried the first order 20K crossover point and it worked wonderfully. Just the type of idea I was after. I was stuck on using a third order network and couldn't see the most simple solution. I'm currently using a very cheap cap, but will soon replace with a more permanent part. Thanks again! Jerrod

My pleasure. I'm only glad whenever I can be of any help!

BR
Roland