ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1] 2 3 ... 7   Go Down

Author Topic: Distance between electrical and audio cables  (Read 19997 times)

Alex Donkle

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 69
Distance between electrical and audio cables
« on: January 14, 2015, 04:08:48 pm »

More of a poll type question, but has anyone here ever come across sound system hum or buzz that was caused by audio cables running next to power cables? Best practice has always been separate the cable types whenever possible for several reasons (including safety), but I've also never seen it actually cause noise problem problems for the sound system when dealing with balanced cables, correctly wired. Nearly all sound system hum I've come across relates to grounding issues. Has anyone ever witnessed a noise issue that was fixed by just moving audio cables further away from power cables?
Logged
Consultant

Mike Sokol

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3351
  • Lead instructor for the No~Shock~Zone
    • No~Shock~Zone Electrical Safety
Re: Distance between electrical and audio cables
« Reply #1 on: January 14, 2015, 05:24:34 pm »

More of a poll type question, but has anyone here ever come across sound system hum or buzz that was caused by audio cables running next to power cables? Best practice has always been separate the cable types whenever possible for several reasons (including safety), but I've also never seen it actually cause noise problem problems for the sound system when dealing with balanced cables, correctly wired. Nearly all sound system hum I've come across relates to grounding issues. Has anyone ever witnessed a noise issue that was fixed by just moving audio cables further away from power cables?

When I used to do a lot of political gigs in DC the lighting guys would lay their cables right on top of my mic lines. That would cause a lot of dimmer hash in the pre-amps. I changed to Canare Star-Quad cable for those runs and that problem went away.   

I did have a problem with a stage that had a big 6" AC power conduit running right under where the bass guitar player stood. When he turned on stage his bass would be quiet or hum like crazy, depending on how his pickups lined up with the path of the conduit under his feet. I corrected the problem by having him switch to the opposite side of the stage.
Logged
Mike Sokol
mike@noshockzone.org
www.NoShockZone.org

TJ (Tom) Cornish

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4260
  • St. Paul, MN
Re: Distance between electrical and audio cables
« Reply #2 on: January 14, 2015, 05:24:46 pm »

More of a poll type question, but has anyone here ever come across sound system hum or buzz that was caused by audio cables running next to power cables? Best practice has always been separate the cable types whenever possible for several reasons (including safety), but I've also never seen it actually cause noise problem problems for the sound system when dealing with balanced cables, correctly wired. Nearly all sound system hum I've come across relates to grounding issues. Has anyone ever witnessed a noise issue that was fixed by just moving audio cables further away from power cables?
AC mains cables?  No.  Dimmers?  Yes.
Logged

TJ (Tom) Cornish

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4260
  • St. Paul, MN
Re: Distance between electrical and audio cables
« Reply #3 on: January 14, 2015, 05:25:41 pm »

I did have a problem with a stage that had a big 6" AC power conduit running right under where the bass guitar player stood. When he turned on stage his bass would be quiet or hum like crazy, depending on how his pickups lined up with the path of the conduit under his feet. I corrected the problem by having him switch to the opposite side of the stage.
All bets are off for single-ended guitar pickups, which are some of the most efficient antennae ever invented by man.  :)
Logged

Mark Cadwallader

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1223
  • Helena, Montana USA
Re: Distance between electrical and audio cables
« Reply #4 on: January 14, 2015, 05:58:14 pm »

Echoing TJ, I have had induced noise through the Clear-Com when I have been too close to the cables powering conventional stage lighting (i.e., dimmers) when up on the fly rail in a theater.   Moving 2' seems to solve the problem. Mark C.
Logged
"Good tools are expensive, but cheap tools are damned expensive."

Lee Buckalew

  • Classic LAB
  • Hero Member
  • *
  • Offline Offline
  • Posts: 1310
  • St. Louis, MO area
    • Pro Sound Advice, Inc.
Re: Distance between electrical and audio cables
« Reply #5 on: January 14, 2015, 06:04:51 pm »

Echoing TJ, I have had induced noise through the Clear-Com when I have been too close to the cables powering conventional stage lighting (i.e., dimmers) when up on the fly rail in a theater.   Moving 2' seems to solve the problem. Mark C.

Standard Clear Com is not a balanced audio signal.

Lee
Logged
Lee Buckalew
Pro Sound Advice, Inc.

Mac Kerr

  • Old enough to know better
  • Administrator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 6419
  • Audio Plumber
Re: Balanced Comm
« Reply #6 on: January 14, 2015, 06:08:35 pm »

Standard Clear Com is not a balanced audio signal.

Nor is Clear Com TW, or RTS. AFAIK the Teles AudioCom is the only balanced belt pack intercom system.

Mac
Logged

Mark Cadwallader

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1223
  • Helena, Montana USA
Re: Distance between electrical and audio cables
« Reply #7 on: January 14, 2015, 06:30:41 pm »

Standard Clear Com is not a balanced audio signal.

Lee

Point well taken. I wasn't thinking about it being unbalanced. Duh!  Mark C.
Logged
"Good tools are expensive, but cheap tools are damned expensive."

Lyle Williams

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1546
Re: Distance between electrical and audio cables
« Reply #8 on: January 14, 2015, 06:35:17 pm »

The 2' suggested is adequate.  If possible power and signal cables should not cross each other, or cross each other at right angles.

But people get away with other setups all the time.  I have power taped to my snake along with ethernet and rf coax.
Logged

Tim McCulloch

  • SR Forums
  • Hero Member
  • *
  • Offline Offline
  • Posts: 19993
  • Wichita, Kansas USA
Re: Distance between electrical and audio cables
« Reply #9 on: January 14, 2015, 06:39:31 pm »


But people get away with other setups all the time.  I have power taped to my snake along with ethernet and rf coax.

Done this for longer than there has been ethernet... ;)

As has been said, dimmers fully loaded and running at 50% are the worst things for noise (and newer dimmers are far less of a problem).  Normal AC service has yet to create any noticable induced noise in our systems.
Logged
"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut
Pages: [1] 2 3 ... 7   Go Up
 


Page created in 0.048 seconds with 23 queries.