ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: 1 2 [3] 4   Go Down

Author Topic: Static Pop  (Read 3646 times)

Dan Mortensen

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 341
Re: Static Pop
« Reply #20 on: February 14, 2017, 02:44:58 pm »

Brian hasn't posted since May of 2015, his last log in was Christmas Eve 2016.

 ???

I zapped a full sized X32 last night that was not connected to a UPS or stage box, and it didn't care in the least. I zapped both the grounded screw near the duplex outlet and the console itself, and it did't react at all.

This makes sense, because it's the AES50 sync that's getting interrupted with UTP problems and not the inner console workings.

So I think it's clear that whatever problems the OP is having are not with the console (assuming it is not malfunctioning somehow) but somewhere else.

I didn't unground the console, though; if that's the problem it should be grounded.
Logged

Mike Sokol

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3007
  • Lead instructor for the No~Shock~Zone
    • No~Shock~Zone Electrical Safety
Re: Static Pop
« Reply #21 on: February 14, 2017, 04:14:07 pm »

You really need two pieces of information to troubleshoot these kind of problems.

1) Under what circumstances is it repeatable? Does it only happen periodically when a light switch is flipped on? Or when a cash register door is opened? Or when someone scuffs their feet on a rug and touches the pulpit mic for the first time? That's the trigger causing the problem.

2) How does the problem manifest itself? Is it a signal dropout? Is it a pop? Is it a buzz? Is it a hum? Is it a level change? That can hint as to where the problem is coming from.

Once you identify the above two things, then you can start speculating as to what's actually happening. I always try to divide and conquer. Shut off all the RF mic receivers to make sure it's not from some RF hit. Turn off the console and see if you can force the problem with just the amplifiers powered up, etc...

Duane Sanders

  • Newbie
  • *
  • Offline Offline
  • Posts: 14
Re: Static Pop
« Reply #22 on: February 14, 2017, 06:17:36 pm »

Duane, you said that you are not using any stage box. How is the signal getting to the console from the stage/altar area? Mic cables? Analog snake?

Are you quite sure that it isn't the operator touching the console when everyone stands up and sparking it with a finger?

Do the mic cables from the stage run below or through that area where the seats were?

You said in the OP that the chairs in that area actually touch the sound booth wall; what is that wall made of, and are there any nails or something similar which when zapped from the chair side run through the wall and touch any metal that touches the mixing console? (You said there was no conduit in the booth.)

Those questions all relate to the part I don't understand: If the collected group of people are collecting a static charge, that should make no difference to the PA until it discharges into the PA or its power. How does that discharge occur? If it jumps through the wall and into the console, that is one thing. If it jumps through the floor into the cables connected to the console, that is another thing. If it's still happening after the seats are removed, that's something else. And how is there a group static discharge from multiple people together so it's worse than from one person?

Did removing the chairs from that area solve the problem or is it still happening? You don't quite say that in your posts.

Is the AC electricity fully using twisted pair plus ground cables? And there is a good connection between X32 ground and earth ground? Asking Jonathan's question a little differently, what is the path to ground from console to ground rod or whatever?

As a separate issue which you don't seem to be having but could: if the console wall power is disrupted or drops below something like 85 volts for more than 2 cycles of the 60Hz sine wave, it will reboot. Meaning no audio till it gets back online.

That can be prevented with a cheap UPS, like $40. You can also solve it with a $1000 true sine wave UPS, but the cheap ones seem to work just fine, too. I use a Cyberpower 350 watt one from Amazon https://smile.amazon.com/gp/product/B004OR0V2C/ref=oh_aui_search_detailpage?ie=UTF8&psc=1  I've read that they are somehow hard on power supplies while simultaneously reading that switching power supplies don't care if the AC wave is sinusoidal or not. I know for a fact that the console doesn't seem to suffer when you yank the power cord to the UPS. I'm not sure which Power Conditioner you use but I don't think those things will take losing power completely for any length of time while keeping the console running.

I'm one of the people who has used a BBQ sparker to test static disruption to X32 signal, and I don't recall checking the ground of the naked (no S16/32 stage box/CAT cable combo) console. This is a very very busy week and I don't think I'll have time to set up a console and try it but maybe Brian Wynn, who discovered the solution to the problem, will read this and have some time.

Good luck, this is an interesting problem.

Well, i am not a sound engineer of any sort.  I am a IT Specialist.  I have been around mixers and speakers and standard stuff for churches for awhile, but i am not versed in all the pro sound terminology.  I can tell you we have a X32 mixer.  their is a snake with XLRs that connect from the back of the mixer to the stage. there is a termination box under the stage.
All of the cables run down the wall where the chairs were.  when we removed the chairs the pop has not happened.   no one has to touch anything when the pop was occuring.  It was so bad for awhile the pastor would tell everyone to get ready for the pop before he asked them to stand.  I actually sat on one of those chairs one morning and i got up to check something and it popped.  funny but not cool.  so it really didnt have to be the whole group.  there are about 12 chairs total.
This wall is made of lumber and sheetrock.  of course there is carpet on floor.
is there a sheilding that i should wrap the snake and other cables in as they go down inside the wall.  there is about 4-5 feet before the cables go into the conduit in the concrete.
The electrical wire is 12-2 MC cable.
I still need to check the grounding on the mixer console and the racks.  i will report back in a few days.
thanks for the thoughts and help.


Logged

Dan Mortensen

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 341
Re: Static Pop
« Reply #23 on: February 15, 2017, 03:37:32 pm »


All of the cables run down the wall where the chairs were.  when we removed the chairs the pop has not happened.   no one has to touch anything when the pop was occuring.  It was so bad for awhile the pastor would tell everyone to get ready for the pop before he asked them to stand.  I actually sat on one of those chairs one morning and i got up to check something and it popped.

Hi Duane,

Thanks for the reply and more info.

You say "all the cables". They are all individual mic cables? Could there be insulation worn off on one of them so that the metal riser is contacting the shield of a cable?

Are they all one run or are they multiple cables connected end to end? If the latter, could one or more of them have pin 1 shorted to the connector body and the body touching the metal riser?

There's a couple possibilities for you to look for.

Dan
Logged

Lee Buckalew

  • Classic LAB
  • Hero Member
  • *
  • Offline Offline
  • Posts: 1197
  • St. Louis, MO area
    • Pro Sound Advice, Inc.
Re: Static Pop
« Reply #24 on: February 15, 2017, 04:30:29 pm »


If the latter, could one or more of them have pin 1 shorted to the connector body and the body touching the metal riser?


Or could they be wired improperly with pin1 and shell wired together?
I still see some manufacturers wiring cable ends this way even though it is not to be done as a standard.

Lee
Logged
Lee Buckalew
Pro Sound Advice, Inc.

Dan Mortensen

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 341
Re: Static Pop
« Reply #25 on: February 15, 2017, 07:43:24 pm »

Or could they be wired improperly with pin1 and shell wired together?
I still see some manufacturers wiring cable ends this way even though it is not to be done as a standard.

Lee
Yes, that is what I meant, although an accidental short would do it just as well.
Logged

Duane Sanders

  • Newbie
  • *
  • Offline Offline
  • Posts: 14
Re: Static Pop
« Reply #26 on: February 16, 2017, 12:40:32 pm »

Hi Duane,

Thanks for the reply and more info.

You say "all the cables". They are all individual mic cables? Could there be insulation worn off on one of them so that the metal riser is contacting the shield of a cable?

Are they all one run or are they multiple cables connected end to end? If the latter, could one or more of them have pin 1 shorted to the connector body and the body touching the metal riser?

There's a couple possibilities for you to look for.

Dan

Hi Dan,
thanks for the input.
I mean all the cables from the Media desk go down into the wall and through the Media Booth floor into the room below where they then go different directions.
we have one monster cable for XLRs.
i have not noticed any insulation missing from any cables.

Logged

Duane Sanders

  • Newbie
  • *
  • Offline Offline
  • Posts: 14
Re: Static Pop
« Reply #27 on: February 16, 2017, 12:45:45 pm »

Hi Duane,

Thanks for the reply and more info.

You say "all the cables". They are all individual mic cables? Could there be insulation worn off on one of them so that the metal riser is contacting the shield of a cable?

Are they all one run or are they multiple cables connected end to end? If the latter, could one or more of them have pin 1 shorted to the connector body and the body touching the metal riser?

There's a couple possibilities for you to look for.

Dan

i will look a little closer on Sunday after the board is powered down.  it could be a connector body issue.
thanks
Logged

Mike Sokol

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3007
  • Lead instructor for the No~Shock~Zone
    • No~Shock~Zone Electrical Safety
Re: Static Pop
« Reply #28 on: February 16, 2017, 06:57:38 pm »

i will look a little closer on Sunday after the board is powered down.  it could be a connector body issue.
thanks

The best way to test for this problem is to a leave everything up and running, then start tapping on cables and connectors one at a time and see if you can make the system pop. Of course, don't do this during a worship service since that won't win you any friends. But if you carefully start at one end of your cable run and tap, twist and giggle every connection and cable, you just might find the culprit.

Dan Mortensen

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 341
Re: Static Pop
« Reply #29 on: March 13, 2017, 12:45:19 pm »

Our new building is about 6 years old and each winter we have had a loud static pop ignite when everyone stands for prayer. It sounds like a handgun being shot, so it is very scary.  It doesnt happen until a few people stand at the same time to create the static buildup.  This is only a winter time event because the air is very dry, which is great for static electricity. 
Our auditorium is built like a bowl with bleacher style seating, so we have this sound booth built in the center of the auditorium with standard wood and sheetrock platform.  There are several rows of pews in front of the sound booth.  The last row is right in front of the sound booth wall.  It actually touches it.  We have narrowed this static pop to this row of chairs so we have removed this row to stop the static pop.  I have not been involved the whole time so i will tell what i know.  Someone installed an extra ground rod under the sound booth and attached it to some copper wire that is ran along the carpet behind the chairs to possibly help remove any static charge coming from the chairs.  dont think that is working, but they tried.
All AV systems are grounded properly that i can tell.
Anyone have any ideas or questions to help understand (and eliminate) this issue? 

Thanks
Duane

Guess this guy bailed. Nearly a month since he posted.

Too bad, it was an interesting problem and I was hoping to learn how the static was entering the system.

Logged
Pages: 1 2 [3] 4   Go Up
 


Page created in 0.118 seconds with 17 queries.