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[Eric Babington]

We are having an issue where the sound in the mains will drop out completely. This happens at random times, but more frequently when the gear is cold. I have been at the church for almost a year and until yesterday, this has only happened twice. Yesterday it happened 3 times during a memorial service. The only way to bring the system back to life is to 'almost' yell into a mic or to turn it up to the point of feedback. After doing this it resumes normal operation.

Some of the troubleshooting that I have done is just to verify settings. There is no gate setup anywhere and there is no change on the board when this occurs and our speakers are not powered. The sound just kind of drops out. We have a Yamaha M7CL console, Behringer Ultradrive Pro crossover, and Yamaha P7000S amps. If you have any experience with this problem, please let me know. I am not sure how to test each of these to discover the underlying issue. Thanks for any help!

[David Sturzenbecher]

Eric, when the sound drops out, do you see signal on the main mix out meters of the M7? Providing you are using the main L/R to drive your system. Like wise does your ultra drive pro give any input output meter indications?


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[Eric Babington]

Eric, when the sound drops out, do you see signal on the main mix out meters of the M7? Providing you are using the main L/R to drive your system. Like wise does your ultra drive pro give any input output meter indications?


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Everything on the board still meters the same. I have not checked the ultra drive. Unless I really have it cranked it normally doesn't show anything on the meters.

[Ivan Beaver]

When you are with the system by yourself (ie not before or during a service), play some music.  Then wiggle all the input/output cables and beat band bump various pieces of gear front and rear.

You have an intermittent somewhere, so you need to giggle it loose.  "technical term"

[Don T. Williams]

I've seen problems like this from several manufacturers that were blamed on dirty internal ribbon cable connectors or cold solder joints.  I think some op amps can "latch up" and then start working when a loud signal was applied.  If you have multiple amps driving speakers, and all the speakers drop out, it would be highly unusual for amps to simultaneously fail.  Are you also using monitors, and do they also drop out also?  If they don't fail and they are not routed through the processor, the processor would be suspect #1.

[Eric Babington]

Thanks Don. Sometimes I can't see the forest for all the trees. The speakers are powered by different amps so the simultaneous failing of all speakers would seem to rule out the amps. Thanks for that.

Ivan, I'll start banging. Thanks for that as well. Unfortunately this is the worst week possible to get some alone time with the equipment. We had streaming for a ludicrously large class that needed overflow, fail, so only half the people saw it yesterday. And we have three more memorials this week as well as some other smaller things going on in the auditorium.

I appreciate you guys taking the time out to help me diagnose!

[Ken Cross]

You may want to listen to headphones as well (assuming you can make it happen again.) The idea here is to try to determine if the issue is in the amp, in the mixer, or in other pieces (assuming they are separate boxes.) You could cycle power to the amp to see if it resets (if so it's likely in the amp.) Then work your way toward the mixer. Cycle power on each item in series. When it begins working again you have your culprit.

Ken

[Andrew Hollis]

Use different outputs. Then at least you know it's not those outs. Though they likely are all on one card anyway.

[Jerome Malsack]

My take on this would be to divide and conquer,  can you take the behringer crossover out of the loop and go to the amplifier that runs the tops.  Not the subs. 
Then with playback music see if you have failures.  This should eliminate the Mixer outputs and bring you down to one other device the behringer crossover. 

[Steve Alves]

Is it possible there is a compressor in the signal chain? When you say yelling into it causes it to come back on a "duck" comes to mind.

[Mac Kerr]

Is it possible there is a compressor in the signal chain? When you say yelling into it causes it to come back on a "duck" comes to mind.

Or a bad solder joint.

Mac

[Steve Alves]

Or a bad solder joint.

Mac

Yeah, but a compressor is easier to check for. I hate when I spend a bunch of time on a problem and it was something simple and obvious I missed.

[Casey Sharp]

It is certainly hard to find a problem if you are unable to recreate it.  It may sound obvious, but start with that. Think back to the times it happened... does anything stick out to you that may have caused it?  If not, play some music and start jiggling inputs and outputs between the console and the amps - it could very well be a bad cable.

Is the system stereo or mono? Do you have delay speakers or front or side fills?  Do you have a video feed and if so did you lose audio to there or to any of the other speakers?  If the answer is yes to any of these then find where those feeds are tapped in and you know it's somewhere between there and the console.

Another thing... Is it a possibility that you just straight up lost power to your amps or DSP?  Was there a pop of any sort when it all came back on?

[Eric Babington]

You guys/girls are awesome. Thanks for all the advice and tricks and pathways to run down. It was the Ultradrive. I replaced it with a DBX PA2 and all is well once again. Thanks for all the help!

[Don T. Williams]

You guys/girls are awesome. Thanks for all the advice and tricks and pathways to run down. It was the Ultradrive. I replaced it with a DBX PA2 and all is well once again. Thanks for all the help!

Just as I suspected!

[ProSoundWeb Community]