JBL 2350 horn questions/ Please advise

[virmagicus]

http://i173.photobucket.com/albums/w62/virmagicus/f82b_1.jpg

Model 2470
Model 2327
Model 2328
Model 2350

I have a couple questions about the following horn that I have just picked up for $ 100.00 for the pair. I am just now getting into a small project and would like to know the correct way to test these. I have been strictly a floor speaker guy for the last 20 years. I am a newbie when it comes to horns. Will I have to run these through a crossover to verify that they work ? These are 16 ohm. I curently have a DBX made amp rated at 250 @ 8 ohm. I would also like to know the correct crossover for this setup. And any necessary info for testing before I test them. I do have a good multimeter. Thanks for any help.

[ChopsMX5]

My help will only be very minimal, but...

Yes, I would say it would definately be advised to run them through a crossover, even if it's just a simple capacitor of proper size and value to knock out any bass that could get to the driver and fry it.

As for the DBX amp, I'm assuming it's most likely the old subwoofer amp that they made years ago for comsumer use? Anyway, it will be fine running the 16 ohm driver.

BTW, nice catch on the horns/drivers for only a 100 bucks! :applaud:

[virmagicus]

My help will only be very minimal, but...

Yes, I would say it would definately be advised to run them through a crossover, even if it's just a simple capacitor of proper size and value to knock out any bass that could get to the driver and fry it.

I figured ... I was unsure if I cutout the lows If it would be ok at low volumes to test.


As for the DBX amp, I'm assuming it's most likely the old subwoofer amp that they made years ago for comsumer use? Anyway, it will be fine running the 16 ohm driver.

It is a configurable b-200

[grumpy]

2470 info:
http://www.lansingheritage.org/images/jbl/catalogs/1980-pro/page19.jpg

Can measure DC ohms first. (somewhere between 8-16 ohms means they're
not shorted or open). They probably have phenolic diaphragms (can go a bit lower,
but not as high as metallic ones). Definitely test with a crossover.

Nice buy! :) -grumpy

[virmagicus]

Can measure DC ohms first. (somewhere between 8-16 ohms means they're
not shorted or open). They probably have phenolic diaphragms (can go a bit lower,
but not as high as metallic ones). Definitely test with a crossover.

Nice buy! :) -grumpy


I have taken the caps off and they look like the original phenolic diaphragms. I am getting a reading of about 9.3 on one and no reading for the other. Both of drivers had red color paint over the top of the screws that appeared to have been untouched. Could this be just a diaphragm replacement ? Thanks for all of the help :D

[grumpy]

worth a bit of cleaning/retest to find out if it's the leads or the diaphragm
(more specifically, the voice coil) that are causing the apparent open circuit,
but there's not much more to it.

Replacing the diaphragm would likely take care of the issue. Someone else
with more experience might tell you if it's ok to treat these as 2420 or 2421
type cores (more diaphragm options).

If you don't have a way to test (sine sweep at a certain voltage & frequency
range), you might want to have this done at a competent shop as alignment
is not guaranteed by just bolting it up. -grumpy

[hpyle]

Yes, definitely try measure resistance at the diaphragm terminals directly - I've had a driver where the disconnect was gunk/corrosion in the push-terminals rather than a blown diaphragm.

I'm running the same horns, crossovers at 400Hz and 6KHz. 400 is really a bit too low, you'd be more comfortable crossing at 800 or so if possible. They sound really good.

The 2470 spec sheet has a frequency response graph showing this driver on the 2350 horn:
http://www.jblpro.com/pub/obsolete/2470.pdf