intermittent speakers

[mattywizzy]

Hi -all, I'v lurked here for a couple of years and learnt an awful lot of information, thanks!!

 

I hope the combined wisdom of the blue room can help,

 

We're having some problems with one of our speakers at the church - mackie SA1530z

at very random times the speaker will cut out, no sound coming from the speaker but there is still power as the blue led is still on. the speaker on the other side is fine, no problems. We've had this problem before and swapped out the the speaker management box (Behringer DCX2496), we've not had problems for a while but yesterday during the preach the speaker cut out again.

 

it's so random that were really struggling to diagnose the problem!

 

you'll probably need more info but this is a start, hopy you can help!

[aidso]

First thing I would do is to swap the outputs from the DCX and see if the problem swaps sides. If so then its the DCX(never seen them do that before though) Second thing is it could be the amp in the speaker its sell. Try running loud music with a lot of low end into it and see if it cuts out quickly(if anything like DB tech its the fets blown in it) If it does cut out with loud music then bring it to an electronics repair shop and they should be able to fix it easy enough.

[MarkPAman]

Hello Matt

 

Well obviously you can open up the ends of all your cables in case there's something not soldered properly but making contact most of the time. You can check that the speaker's not overheating (unlikely in this case I'd have thought). You can also try giving each part of the system a thump to see if that reveals any bad connections.

 

If the above does not help then things get more difficult. Intermittent faults are hard to find, even if you have the equipment in front of you. I think the best we can hope to do is narrow things down a bit, though this may take some time if the problem does not happen that often.

 

Are you able to swap the left & right speakers over? If you do this, then next time the problem occurs you will know that is either in the speaker cab (DSP/amp etc), or before the speaker (cable/DXC/desk etc).

 

Only swap one thing at a time though, or you won't learn anything new.

 

 

Oh - another thought. Do these speakers have the auto power off function that the SRM450 has. I find that this can cut off when the volume is low (but not off) for a long time. Though I think this causes the blue LED to go out :blink: so it can't be that.

[mattywizzy]

thanks for the prompt replies, We'll try some of your suggestions tonight and see how it goes. Unfortunately I can't swap the speakers over as they are in cradles and not very easy to access ( I know its not ideal but its what we've got)

Don't think the 1530's have auto off like the 450's but I'll check.

[Rob_Beech]

Those auto off things are stupid. I've never known one to be set at a sensible level yet.

 

Some of the only Behringer gear I still own sits in a room at home (B2031A's and the matching sub) and these have auto off. I have to have the volume at a measured 102dB C at my listening position for them to stay on, any lower and the power goes. within a few minutes.

[cedd]

The srm450's had a reasonably keen thermal cut out on them. My SA1521's (the SA1530's smaller brother) have never been a problem, but I've seen a couple of 450's that have cut out just as you described. I'd have thought that the thermal LED would have lit on the back of the unit though.

I too have never seen a DCX do this and would second the swapping of outputs idea. It should prove reasonably conclusive.

 

Edit just to say; I know your units aren't 450's, I'm jsut saying that there have been problems with them and it could possibly be the same thermal circuit in both units, mine have never been a problem though.

[mattywizzy]

just another thought we have a graphic EQ (cant remeber for the life of me what make/model) in front of the LMS,

signal runs desk>GEQ>LMS>Spkrs

could it be the EQ causing problems? I could use the EQ on the LMS and remove the existing GEQ, is it worth it? am I wasting my time.

 

I agree the auto off is pointless!!

[handyandi]

As mentioned by previous posters 1st point of fault finding is to see if its the individual speaker at fault. Should not matter that you have no access to them just find the 2 cables feeding signals to them for example the outputs of the DCX and swap them over. Left feeds right etc & if the problem appears at the same cab again it must be the cab, if it occurs on the other cab it must be something further back up the signal chain. You can then trace it further by the same method, or by removing say the DCX temporarily & then the EQ etc.

Hope this helps

 

Andi

[Kevin Ross]

could it be the EQ causing problems?

 

Maybe.

 

With trouble shooting I subscribe to the school of thought “Make it as simple as possible and then add things until it breaks” With that in mind I would run it from the desk straight into the speakers and play some music for a few hours, still working? Great add the DCX back in and repeat. Then just keep on going.

 

 

 

I would also echo the comments of swapping the L&R over to see if the problem jumps then you know it is not the speaker itself.

[soundgeek]

Yeh Ill second the pointless auto off! Ive just got some 450s and cant see the point. I mean I can see it if they are up in a rig but yeah!

[MarkPAman]

Should not matter that you have no access to them just find the 2 cables feeding signals to them for example the outputs of the DCX and swap them over. Left feeds right etc & if the problem appears at the same cab again it must be the cab

 

Or the cable(s) that is(are) after the point where you swapped things :P

 

Don't forget about cables. At college they are usually second favorite for being the cause of a fault, after operator error :blink: