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Author Topic: Noise/static elimination  (Read 4572 times)

Stephen Swaffer

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Noise/static elimination
« on: October 23, 2015, 01:19:16 pm »

I have been fighting noise on our church sound system for months.  Very erratic sometimes very minimal other times unbearable.  I have chased it and one time it seems like it is from one mic or set of mics, the next somewhere else.  I was able to eliminate (or at least greatly reduce it) for about 2 weeks by cleaning all of the jacks on the platform with De-oxit.

Unplugging nearly all of the mics at the mixer also helps-though it defeats the purpose!

Most of the mic jacks have been in place 10 years or longer and we use special effects every year at Christmas time that I can't help but think contribute to degrading of the jacks.

I have recommended wholesale replacing the jacks, but am being asked my confidence level in this curing the problem.  The mixer is an A&H GL3800.  (Which I recently cleaned ) Could there be a problem with the mixer making it more susceptible to static, or does my approach seem reasonable?
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Lee Buckalew

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Re: Noise/static elimination
« Reply #1 on: October 23, 2015, 08:29:22 pm »

I have been fighting noise on our church sound system for months.  Very erratic sometimes very minimal other times unbearable.  I have chased it and one time it seems like it is from one mic or set of mics, the next somewhere else.  I was able to eliminate (or at least greatly reduce it) for about 2 weeks by cleaning all of the jacks on the platform with De-oxit.

Unplugging nearly all of the mics at the mixer also helps-though it defeats the purpose!

Most of the mic jacks have been in place 10 years or longer and we use special effects every year at Christmas time that I can't help but think contribute to degrading of the jacks.

I have recommended wholesale replacing the jacks, but am being asked my confidence level in this curing the problem.  The mixer is an A&H GL3800.  (Which I recently cleaned ) Could there be a problem with the mixer making it more susceptible to static, or does my approach seem reasonable?

Can you describe the "static" or do you have a recording of it that you could link to?

Does it occur only when...
Congregants present
Choir or musicians are in place
Certain days of the week or times of day
Etc.,
Etc.

Have you tried unplugging only at the stage or have you unplugged connections from the console?
Unplugged one at a time (while soloing the output to headphones) and then plugged that one back in and moved on or unplug, leave unplugged, unplug next, leave unplugged, unplug next... until all are unplugged?

More detail will help us to help you troubleshoot.

Lee
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Ivan Beaver

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Re: Noise/static elimination
« Reply #2 on: October 23, 2015, 08:51:59 pm »

Lee has given some good advice.

The whole "trick" is to divide and conquer.

Just because a console was "cleaned" does not mean anything.

What exactly was "the cleaning"?

Start with listening (solo) on each channel to see what channels are causing the problem.

Then unplug the input to that channel?  Did the problem go away?

You said that unplugging "most" of the connectors helped?  What were you listening to at that point?

You HAVE to go channel by channel.

That tells you which way to start to look-the console or the input.

If it is the jacks are on stage, then using some contact cleaner (NOT WD40!!!!!!) and spraying into the jack and working a CLEAN connector in and out can help to clean it.

 But if the problem is in the mixer-replacing the jacks on stage is a waste of time and money.
« Last Edit: October 23, 2015, 08:54:20 pm by Ivan Beaver »
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Stephen Swaffer

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Re: Noise/static elimination
« Reply #3 on: October 23, 2015, 11:34:56 pm »

Cleaning consisted of unplugging every ribbon connector and cleaning with de-oxit followed by de-oxit gold per manufacturers recommendations.

I will try to post a recording.  Best description is a very "airy" sometimes faint, often is hardly noticed by congregation, but at times can be very harsh.

I thought maybe a CFL ballast, but on a Saturday afternoon. With all lights in building off still had the issue.

Soloing does not help-noise is present in mixer no matter what I listen too-solo any channel, main, L-R.

This last service, pastor asked me to "do something".  Choir mics have seemed to contribute most to the problem so I unplugged them at the mixer and things improved greatly-pastor's dad was preaching so he text me that got it.  About 3 minutes later more static.  His dad was using a cordless mic so, I pulled other mics.  Still had 7 wireless plugged in, as well as 3 wired mics-baptistery, pulpit and piano, but zero static for the ready of service-say 45 minutes or so.

As for doing one at a time, I'd love to - that is basic troubleshooting, but the Saturday I had the lights off I thought I had it after a change but 15 minutes later more noise.  I suppose I could spend 2 or 3 40 hour weeks but that seems like an excel is in futility.
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Lee Buckalew

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Re: Noise/static elimination
« Reply #4 on: October 24, 2015, 12:38:23 am »

Cleaning consisted of unplugging every ribbon connector and cleaning with de-oxit followed by de-oxit gold per manufacturers recommendations.

I will try to post a recording.  Best description is a very "airy" sometimes faint, often is hardly noticed by congregation, but at times can be very harsh.

I thought maybe a CFL ballast, but on a Saturday afternoon. With all lights in building off still had the issue.

Soloing does not help-noise is present in mixer no matter what I listen too-solo any channel, main, L-R.

This last service, pastor asked me to "do something".  Choir mics have seemed to contribute most to the problem so I unplugged them at the mixer and things improved greatly-pastor's dad was preaching so he text me that got it.  About 3 minutes later more static.  His dad was using a cordless mic so, I pulled other mics.  Still had 7 wireless plugged in, as well as 3 wired mics-baptistery, pulpit and piano, but zero static for the ready of service-say 45 minutes or so.

As for doing one at a time, I'd love to - that is basic troubleshooting, but the Saturday I had the lights off I thought I had it after a change but 15 minutes later more noise.  I suppose I could spend 2 or 3 40 hour weeks but that seems like an excel is in futility.

You have not yet described the noise.
Is it like bacon frying?
Is it like the background noise of a vinyl record?
Is it like pink noise?
Is it like white noise?
Is it a constant sound (when it is occurring) or does it change?
In what way does it change?
Is there a noticeable pattern?

Does it only happen when other people are present (along with their electronic devices) or does it also happen with no one else around?

Are you saying that the noise is present through headphones no matter what you have soloed?

What is the sound console?

Lee
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John Roberts {JR}

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Re: Noise/static elimination
« Reply #5 on: October 24, 2015, 08:06:33 am »

Cleaning consisted of unplugging every ribbon connector and cleaning with de-oxit followed by de-oxit gold per manufacturers recommendations.

I will try to post a recording.  Best description is a very "airy" sometimes faint, often is hardly noticed by congregation, but at times can be very harsh.

I thought maybe a CFL ballast, but on a Saturday afternoon. With all lights in building off still had the issue.

Soloing does not help-noise is present in mixer no matter what I listen too-solo any channel, main, L-R.
This suggests noise is output related. So stop wasting time cleaning input jacks.
Quote
This last service, pastor asked me to "do something".  Choir mics have seemed to contribute most to the problem so I unplugged them at the mixer and things improved greatly-pastor's dad was preaching so he text me that got it.  About 3 minutes later more static.  His dad was using a cordless mic so, I pulled other mics.  Still had 7 wireless plugged in, as well as 3 wired mics-baptistery, pulpit and piano, but zero static for the ready of service-say 45 minutes or so.
inputs? this disagrees with earlier statement.
Quote
As for doing one at a time, I'd love to - that is basic troubleshooting, but the Saturday I had the lights off I thought I had it after a change but 15 minutes later more noise.  I suppose I could spend 2 or 3 40 hour weeks but that seems like an excel is in futility.
You must divide and conquer, otherwise you are just hoping to get lucky,

It may not be one simple connection, could be an external noise source getting in through one of multiple vectors.

Start by isolating all the things it isn't. When finished what's left is what it is. (sorry about the cliche).

Does the noise fall and go away when you drop the main fader?

You will find it eventually but it will take some time and effort.

JR

PS Noise can come in through outputs and even through power cords, so keep looking at everything.
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Ivan Beaver

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Re: Noise/static elimination
« Reply #6 on: October 24, 2015, 09:30:31 am »



Soloing does not help-noise is present in mixer no matter what I listen too-solo any channel, main, L-R.


Please don't take what I am going to say the wrong way.

I have dealing with "other people troubleshooting" over the phone for many years.

VERY often people say things that simply are not true-or they don't know the answer to and they "give an answer" even though they don't know the answer.

This seemingly innocent statement can cake somebody who actually knows what is going to chasing off in a wrong direction.

This is true when talking to your doctor, auto mechanic etc.

It is FAR FAR better to simply say "I don't know" rather than give a  wrong answer.

First of all-am I to "assume" that you are "properly soloing?"

Meaning listening to ONLY ONE channel at a time? Making sure ALL OTHERS are NOT engaged?

And by "soloing" I am again assuming you are listening on headphones and not just pressing solo button while listening to the speaker system.

There are all kinds of people who say things that we assume are being done properly, but they are not doing that

All that being said-with the statement I copied above from your post, there are only 2 places the problem could be.

Either the power supply in the console-or a something in a "master board" (I don't know how your console is electrically/physically laid out) that is on a "master board" that also has the solo amp on it.

Have you tried simply "beating on the console? dropping it a couple of inches and such?

You could have an intermittant in the console.

It DOES NOT sound like it would be outside the console.

But it could be-but I would not even begin to look there-BASED on the statement I copied.
« Last Edit: October 24, 2015, 09:40:00 am by Ivan Beaver »
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Stephen Swaffer

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Re: Noise/static elimination
« Reply #7 on: October 24, 2015, 10:37:11 am »


It may not be one simple connection, could be an external noise source getting in through one of multiple vectors.

Start by isolating all the things it isn't. When finished what's left is what it is. (sorry about the cliche).

Does the noise fall and go away when you drop the main fader?

PS Noise can come in through outputs and even through power cords,

This is what I feel like is happening-external noise coming in through multiple vectors.

Perhaps a better description would be like the static you hear on an AM radio during a distance thunderstorm.  Completely random fades in and out then stops completely then comes back-or not!  The only thing that seems to affect it is disconnecting inputs-or in some cases shutting off phantom power to mics seems to help.  Disconnecting something seems to be a definite cure-noise stops instantly, then it r-occurs at some random time even with that stil disconnected.  Makes me think I am disconnecting the "antenna"-or one of them.

The console is an A&H GL3800.  The Saturday I was working in it, I had the building to myself.  I did have my phone on me-not a smart phone.  Turning off the console did completely eliminate the noise. 

Yes, I hear the noise no matter what is soloed.

So it is not the amps/outboard gear-definitely getting into the mixer.
It is not an isolated channel-at least not on signal wires because it happens even with everything muted.

Ivan, I understand. My background is troubleshooting industrial machinery.  I was the go to guy in a facility for a number years until I got tired of factory life, so I am usually very thorough and have experience on the receiving end of tech support.

Yes, I am soloing as you describe.

If console repair/removal and substitution for repair and jack replacement were anywhere near the same amount of "pain and suffering", I'd likely lean towards the console for something to try.  If I could consistently re create the problem I would.
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Steve Swaffer

Lee Buckalew

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Re: Noise/static elimination
« Reply #8 on: October 24, 2015, 10:49:50 am »

So, with all inputs and all outputs disconnected you still get the noise through the headphones either when any individual input or output is soloed?

Does this also occur when your phone is off (not silent, off)?

If all of this is the case and you have thoroughly isolated the problem to the console/PS and eliminated the possibility of RF then you know what needs to be tested.

Lee
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John Roberts {JR}

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Re: Noise/static elimination
« Reply #9 on: October 24, 2015, 01:32:59 pm »

This is what I feel like is happening-external noise coming in through multiple vectors.
Even if noise is entering from multiple vectors it is probably being rectified or made audible in only one isolated section or block.
Quote
Perhaps a better description would be like the static you hear on an AM radio during a distance thunderstorm.  Completely random fades in and out then stops completely then comes back-or not!  The only thing that seems to affect it is disconnecting inputs-or in some cases shutting off phantom power to mics seems to help.  Disconnecting something seems to be a definite cure-noise stops instantly, then it r-occurs at some random time even with that stil disconnected.  Makes me think I am disconnecting the "antenna"-or one of them.
perhaps... If cumulative antenna effect it would vary in intensity maybe reaching as threshold amount with X number of mic channels, doesn't matter which just how many.
Quote
The console is an A&H GL3800.  The Saturday I was working in it, I had the building to myself.  I did have my phone on me-not a smart phone.  Turning off the console did completely eliminate the noise. 
That only confirms problem is not the power amp/speakers/speaker wires... while these need to be ruled out.
Quote
Yes, I hear the noise no matter what is soloed.
are we talking about same thing... Solo isolates just one input so you hear the noise  in every input, even just listening to one at a time?

That points toward the master section of console, ASSuming there is no other source feeding the master out. Some consoles have additional line inputs (or alarm feeds) that hit the master even with inputs muted. Does the noise go away when you drop the master fader? (I ASKED THIS ONCE BEFORE BUT DO NOT SEE AN ANSWER).
Quote
So it is not the amps/outboard gear-definitely getting into the mixer.
It is not an isolated channel-at least not on signal wires because it happens even with everything muted.
Does everything "muted" include the master fader output?
Quote
Ivan, I understand. My background is troubleshooting industrial machinery.  I was the go to guy in a facility for a number years until I got tired of factory life, so I am usually very thorough and have experience on the receiving end of tech support.
does the noise go away when you drop the master fader?
Quote
Yes, I am soloing as you describe.

If console repair/removal and substitution for repair and jack replacement were anywhere near the same amount of "pain and suffering", I'd likely lean towards the console for something to try.  If I could consistently re create the problem I would.
Not crazy to swap in a small mixer just to test and confirm no larger systemic issue.

I may need to look at that console routing to understand master section logic. If you get it with inputs muted, it isn't an input.

Do you get noise with master fader pulled down?

JR
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Re: Noise/static elimination
« Reply #9 on: October 24, 2015, 01:32:59 pm »


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