Speaker Cutting Out

Eboy87

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Joined
May 3, 2004
Location
Chicago, IL
I've got a pair of JBL SR4722's that I use for my sound system (duh). I got them for free when the guy who leads the guitar choir at my church bought a new sound system.

My problem is, when I'm running my rig softly (I use my system as the stereo in my room), the woofer on one cuts compleatly, while the tweeter, or horn, or whatever the top thing is (a pic might follow later on) gets considerably quiter. I know it's not in the wiring of my rack, or the amp, I've narrowed it down to the speaker, but the funny thing is, when I increase the volume, it pops and comes back on. Oh yea, I should mention it works quitley for a short time, 2 or 3 minutes, then cuts out,

I wanted to know if this might be something I'd be able to fix at home, versus sending it out somewhere to be fixed, or even if it is a serious problem. Thanks in advance
 

Peter

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Oct 2, 2004
Location
MA, USA
Hmm the subwoofer in my parents home theator system does this too... I think it's some kinda power save thing or something.... It's fine b/c it bascily cuts off during parts of the songs or the talking inbetween that does not need bass and then comes back on when there is alot of bass. Not sure if something similar is happening with your speakers (they think there is not enough bass at that volume to necessitate the woffer). Not sure why this would happen on a Pro speaker though.
 

wolf825

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Eastcoast USA
Could be one of two things based on your description--bad cable connection (i.e. your cable connection is dirty or gummed and not making full contact until it gets a larger voltage, or is not seated--1/4" perhaps?-make sure its TS and not TRS--that can cause you issues), or your passive crossover is faulty and dying. Check all the cable connections including your speaker cable--run an eraser over the 1/4 jack if that is what you have, and check its continuity on all cables or change cables. See if that fixes things. Failing that--it sadly then leaves your crossover and internal wiring..but the good news is that this is easily replaceable and fixable.

JMO...need more information...
-w
 

mbenonis

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We have the same speakers at school (or very close, ours are SR-X 4722's). These speakers use Speakon connectors that are very well built, so I wouldn't think that could be the problem. It could be the cable though - our Speakon cables have come undone a few times. I would check these thoroughly.

Although you say you've narrowed it to the speakers, this problem sounds very much like a misconfigured gate in your rack. Do you have any gates/compressors, and if so, can you report what model they are and how they are configured?

Also, are the 4722's bi-amped? If so, where is the signal split?
 

Eboy87

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May 3, 2004
Location
Chicago, IL
My speakers I think came out before Speakon cables did. I'm using 1/4" TS connections to power them, and, yes, I do have a gate/comp. It's the Alesis 3630. Here's the settings.

Comp.
Stero-linked
Threshold- -3dB
Ratio- 2:1
Attack- 5 ms
Release- 2s
Output- 0dB

Gate
Threshold- -30dB
Rate- 2s

I'm just using the full range input on the back panel (not bi-amplified), and the toggle switch it set to +2dB.

I'll try using a different cable, annd see if that'f the culprit. I'll be back with the results of that later.
 

AVGuyAndy

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May 1, 2005
Go straight from your board to the amp. See if the problem still exists.
 

mbenonis

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Eboy87 said:
Gate
Threshold- -30dB
Rate- 2s

I'm just using the full range input on the back panel (not bi-amplified), and the toggle switch it set to +2dB.
Aha, as I suspected. Set the threshold to as low as it can go, and see if it helps. This has happened to me a number of times in my rig; I'll have the gate set for a live show and when I go to play a soft song, it cuts in and out. Usually I'll just bypass the gate when I listen to quiet music.
 

Eboy87

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Joined
May 3, 2004
Location
Chicago, IL
No, the gate isn't the problem. When I say softly, the gate is still open, and the other speaker workes just fine. I really do think it may be the crossover in the speaker itself, but I had a show at school today and couldn't do more testing on it, but I asked one of the guys helping with crew who is a live sound engineer (he worked on an NSYNC tour I think) and he agrees that it sounds like a crossover problem.

Which brings another question. How hard is it to aquire/change a crossover? Will any one work, or do I have to track down an old one for this model?
 

Mayhem

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Jan 21, 2004
Location
Australia
The first thing that I do when I have a system that develops a fault on one side only, is I begin to swap sides. In this case, I would swap the speakers and check again. If no change, I would then swap the speaker leads over and test again and repeat this process for every lead/equipment in the signal path.

It sounds as if you may have already done this – so I will move on to the cross over question:

The cross over should be mounted on the back of the input panel (I think it is one unit on these boxes) and should be fairly easy to fix as passive cross overs are really just a network of inductors and capacitors.

Have a look at how the speakers are connected and if you feel confident, I would actually swap over the cross overs from the faulty box to the working box and see if the problem moves with the cross over. If it does, then you know that the cross over is causing the fault. If not, then you could have a problem with the driver.

If it is the cross over, then have a good look for mechanical faults. Broken or dry solder joints or components. Don’t be afraid to give all the components a good wiggle as you may have a joint that looks good but is making poor contact. Depending upon the number of capacitors, you may wist to replace them if you don’t find any other faults. Inductors are a bit more difficult to test as you need a specific meter to test inductance. However, I have never seen an inductor fail before.
Also check the switch contact and give the switch a squirt of electrical cleaner/lubricant.
 

Radman

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Apr 9, 2004
Location
Franklin, TN
I think by 'my sound system' he means 'my pro sound system that I use for pro stuff'. Easily misunderstood, I suppose.
 

Eboy87

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May 3, 2004
Location
Chicago, IL
Yeah, it's the pro system that I use for concerts and such. I only called it my because my other "stereo" stereo broke, so I just use this. I cheked with some local sound companies, and they said it was the compressor. It's been fixed now.
 

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