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Author Topic: Loud Crack in PA  (Read 5092 times)

Ben Haines

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Loud Crack in PA
« on: November 07, 2016, 09:12:11 am »

Hello - new to this site and thanks for reading this post.

We've been having issues with a soundsystem making a loud crack sound.  It almost sounds like lighting.  Here's the set up - x32 through analog snake to stage - dbx crossover to two crown amps plugged into the wall.  I've replaced the crossover, the amps, and tried plugging them in different locations but it still seems to be happening. 

Unfortunately, the outlets all share a breaker box with things like coffee makers, fridges, and AC units.  Could this be causing our issue within the box?  The sound seems to be happening even with amp volumes down.  Here's a video of the sound.  https://vimeo.com/186150776/f8b148a907

Any help is greatly appreciated!  Having an electrician out this week, but not sure they'll be of any help diagnosing. 

Thanks
Ben
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Ray Aberle

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Re: Loud Crack in PA
« Reply #1 on: November 07, 2016, 09:40:32 am »

Hello - new to this site and thanks for reading this post.

We've been having issues with a soundsystem making a loud crack sound.  It almost sounds like lighting.  Here's the set up - x32 through analog snake to stage - dbx crossover to two crown amps plugged into the wall.  I've replaced the crossover, the amps, and tried plugging them in different locations but it still seems to be happening. 

Unfortunately, the outlets all share a breaker box with things like coffee makers, fridges, and AC units.  Could this be causing our issue within the box?  The sound seems to be happening even with amp volumes down.  Here's a video of the sound.  https://vimeo.com/186150776/f8b148a907

Any help is greatly appreciated!  Having an electrician out this week, but not sure they'll be of any help diagnosing. 

Thanks
Ben
Hi Ben,

First of all, per the Rules of Participation here on the ProSoundWeb, your Display Name does need to reflect your Real, Full Name -- since you signed off "Ben," and "Ben" isn't part of your Display Name, it's not clear that this is the case, which means your post may get locked by a Moderator and we will be unable to assist you until it's brought into compliance. Would you mind popping back into your Profile and changing the Display Name as necessary?

As to your problem, WHEN is it happening? At random? Or specific intervals? In other words, are there any consistencies?

-Ray
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Ben Haines

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Re: Loud Crack in PA
« Reply #2 on: November 07, 2016, 03:19:53 pm »

Hi Ben,

First of all, per the Rules of Participation here on the ProSoundWeb, your Display Name does need to reflect your Real, Full Name -- since you signed off "Ben," and "Ben" isn't part of your Display Name, it's not clear that this is the case, which means your post may get locked by a Moderator and we will be unable to assist you until it's brought into compliance. Would you mind popping back into your Profile and changing the Display Name as necessary?

As to your problem, WHEN is it happening? At random? Or specific intervals? In other words, are there any consistencies?

-Ray

It seems to be at random.  There's no specific interval and it seems that once it happens, it doesn't happen again - although once it happened twice within 10 minutes. 
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Tim McCulloch

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Re: Loud Crack in PA
« Reply #3 on: November 07, 2016, 04:27:35 pm »

Ben, that sounds a lot like a temporary loss of word clock.  There is a known issue when using the X32/M32 and the corresponding digital snake stage boxes (requires shielded CAT5e w/Ethercon connectors to fix) due to ESD.  I think it odd you'd have this problem without an S16 on the stage but who knows?

If this problem occurs in the monitor sends, recording feed or streaming output I believe you have a console issue.  Call the Music Group CARE facility in Las Vegas and talk to an X32/M32 support person.

Should this be only in the PA mains the problem is most likely downstream of the mixer and involves wiring and not amps or crossovers.  Has there been any construction or other work taking place where the system wiring is installed?
« Last Edit: November 07, 2016, 04:29:46 pm by Tim McCulloch »
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Ben Haines

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Re: Loud Crack in PA
« Reply #4 on: November 07, 2016, 05:06:07 pm »

Ben, that sounds a lot like a temporary loss of word clock.  There is a known issue when using the X32/M32 and the corresponding digital snake stage boxes (requires shielded CAT5e w/Ethercon connectors to fix) due to ESD.  I think it odd you'd have this problem without an S16 on the stage but who knows?

If this problem occurs in the monitor sends, recording feed or streaming output I believe you have a console issue.  Call the Music Group CARE facility in Las Vegas and talk to an X32/M32 support person.

Should this be only in the PA mains the problem is most likely downstream of the mixer and involves wiring and not amps or crossovers.  Has there been any construction or other work taking place where the system wiring is installed?

From what I'm told - it happens in the monitors as well.  I did a lot of research into that issue with the x32 and had reached out to care, but dismissed most of what I found because we're using an analog snake.  We also have an Allen & Heath M1 monitoring system in place via the dante card in the x32.  Could that somehow be interfering with our outputs of the console?

There hasn't been any recent construction and this only started happening once we replaced old amps, with newer and more powerful ones. 

Thanks for the help!
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Jonathan Johnson

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Re: Loud Crack in PA
« Reply #5 on: November 07, 2016, 05:21:33 pm »

It seems to be at random.  There's no specific interval and it seems that once it happens, it doesn't happen again - although once it happened twice within 10 minutes.

The only thing more frustrating than something that doesn't work when it should is something that does work when it shouldn't.
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Mike Sokol

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Re: Loud Crack in PA
« Reply #6 on: November 07, 2016, 07:36:49 pm »

The only thing more frustrating than something that doesn't work when it should is something that does work when it shouldn't.

I had something similar in a church once, but from your video I can't see if it's happening. When the preacher walked across the worship platform and touched the podium mic for the first time, there was a really loud pop like in your video. He could then touch the mic multiple times after that without a pop. However, if he walked away and walked back to the mic ti would pop again. Turns out they had installed new carpet that was really building up a static charge when the preacher shuffled his feet. So is anyone on stage feeling a static jolt during the "pop"? That would be a big clue.
« Last Edit: November 07, 2016, 07:44:04 pm by Mike Sokol »
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Caleb Dueck

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Re: Loud Crack in PA
« Reply #7 on: November 07, 2016, 07:42:02 pm »

I had something similar years ago.  It wasn't static electricity, our first guess, but a dying DSP.   Took a while to track down, until I noticed it happen with no signal leaving the mixer. 
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Ben Haines

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Re: Loud Crack in PA
« Reply #8 on: November 07, 2016, 07:43:44 pm »

I had something similar in a church once, but from your video I can't see if it's happening. When the preacher walked across the worship platform and touched the podium mic for the first time, there was a really loud pop like in your video. But he could touch the mic multiple times after that without a pop. But if he walked away and walked back to the mic ti would pop again. Turns out they had installed new carpet that was really building up a static charge when the preacher shuffled his feet. So is anyting on stage feeling a static jolt during the "pop"? That would be a big clue.

Ha yes I've read about that as well.  No one reports getting a shock and sometimes has happened with no one on stage even.  Stage is wooden though as well - no carpet here. 
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Robert Lofgren

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Re: Loud Crack in PA
« Reply #9 on: November 07, 2016, 08:16:33 pm »

How is your clock sync setup?

X32 should be slaved to 'card' unless the x32 is the prefered master in the dante network.
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Mike Caldwell

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Re: Loud Crack in PA
« Reply #10 on: November 07, 2016, 08:42:25 pm »

Yea that gets your attention!!

You said it still will do it with the amp levels turned all the way down.

Has anyone ever noticed any level metering, clip indicators, ect on any of the equipment
when this happens.

On the board by chance have you noticed any channel peak with an extreme amount
of signal level when you hear the noise, I'm sure you see all the open mic channels pick it
but this would be a slammed peak on a channel.

As for the monitors, is it in the wedges and in the M1 ear monitor system, that could hard for them
to tell if it is actually in the monitor system or they could just be hearing the sound picked up
from the open mics and that being fed into the monitors.

Do you have any direct board out recordings made at the same time you heard noise, if so
what's does the recording sound like, if you don't make a stereo maybe try recording
one till you catch the noise on a recording.
Maybe for the sake of testing set a multi track recording system to hopefully
catch something on one of the input channels.

Do you have phantom power on any channel.

Does it do it with the board muted and or every channel and the mains turned down.

Try moving/wiggling every connector and cable starting on the stage, to the board, to the amps, don't forget the power cords.


Mike Sokol

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Re: Loud Crack in PA
« Reply #11 on: November 08, 2016, 06:36:32 am »

If these are "new" power outlets in an "old" room, be suspicious of the wiring. That's when the DIY volunteers and painters do wiring that's not correct or to code.  I would start with a ground impedance test on all the AC power outlets. Back in the day I played in a bar that had new power outlets installed across the back of the stage. Looked nice with grounded receptacles, but while all the grounds on the branch circuit were tied together, the EGC ground wires wires never bonded to anything, it was all floating together. So when a cash register on the same branch circuit would open, the drawer solenoid would dump a big voltage spike back into the floating ground wire and make a really loud pop in the PA system, just like the one you're experiencing. See if you can borrow an Amprobe INSP-3 or SureTest Analyzer and confirm that that ground impedance is less than 1 ohm. Or just measure it with a voltmeter to confirm it's withing a few volts of the Neutral line while under building load.
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Stephen Swaffer

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Re: Loud Crack in PA
« Reply #12 on: November 08, 2016, 01:06:11 pm »


There hasn't been any recent construction and this only started happening once we replaced old amps, with newer and more powerful ones. 


Loose wire any where in the power system to the amps?  Older amps with linear power supplies might be less susceptible to an intermittent power connection?  Anything from a wire nut in a box to a loose neutral connection-though probably localized to the power amp circuit(s).  Run a heavy extension cord to a different circuit to divide and conquer the problem.
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Steve Swaffer

Ben Haines

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Re: Loud Crack in PA
« Reply #13 on: November 11, 2016, 10:07:31 am »

How is your clock sync setup?

X32 should be slaved to 'card' unless the x32 is the prefered master in the dante network.

So I've looked into this and it was set to external - it's since been changed to internal, and all dante network equipment has been removed.  Is it possible that the x32 is having issues within itself? 

I've been saying all along that it's a power issue, but have had trouble convincing our team to look into hiring an electrician.  Any way it could be power in a building maybe 10 years old?
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Ben Haines

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Re: Loud Crack in PA
« Reply #14 on: November 11, 2016, 10:10:22 am »

Yea that gets your attention!!

You said it still will do it with the amp levels turned all the way down.

Has anyone ever noticed any level metering, clip indicators, ect on any of the equipment
when this happens.

On the board by chance have you noticed any channel peak with an extreme amount
of signal level when you hear the noise, I'm sure you see all the open mic channels pick it
but this would be a slammed peak on a channel.

As for the monitors, is it in the wedges and in the M1 ear monitor system, that could hard for them
to tell if it is actually in the monitor system or they could just be hearing the sound picked up
from the open mics and that being fed into the monitors.

Do you have any direct board out recordings made at the same time you heard noise, if so
what's does the recording sound like, if you don't make a stereo maybe try recording
one till you catch the noise on a recording.
Maybe for the sake of testing set a multi track recording system to hopefully
catch something on one of the input channels.

Do you have phantom power on any channel.

Does it do it with the board muted and or every channel and the mains turned down.

Try moving/wiggling every connector and cable starting on the stage, to the board, to the amps, don't forget the power cords.

I can say for sure that it's not a loose connection.  I've heard those and it is no where even close to this loud.
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ProSoundWeb Community

Re: Loud Crack in PA
« Reply #14 on: November 11, 2016, 10:10:22 am »


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