GAIN11

The Art & Science of Audio & Video

Powered stage monitors make me buzz…

PROBLEM: We are using powered stage monitors and we are experiencing a loud buzz. We’ve switched cables and speakers to no avail. The monitors are fed from the FOH up in the organ loft. Are we picking up noise somewhere along the way?

SOLUTION: The stage and the main equipment location in the organ loft are probably not on the same circuit. This is causing two problems; (1) with tri-phase power the two locations are not on the same phase meaning they are 120 degrees out of phase with each other and (2) they are not sharing the same ground reference. Solutions are numerous and ranging from a few hundred dollars to several thousand. The ideal solution would be to have an electrician add a dedicated circuit on the stage for the monitors that originates from the same electrical panel as the power for the main equipment location. Other quick fixes to try would be adding high quality isolation transformers between the mixer and the monitor. Jensen Transformers are an excellent choice, cheap transformers tend to saturate at low frequencies causing distortion. In addition to transformers try simply lifting Pin 1 or the shield wire at the input to your monitor. These will probably lessen the noise but more than likely will not get rid of it.

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March 4, 2008 - Posted by | Troubleshooting | , , , , , ,

2 Comments »

  1. […] gain11 wrote an interesting post today onHere’s a quick excerptPROBLEM: We are using powered stage monitors and we are experiencing a loud buzz. We’ve switched cables and speakers to no avail. The monitors are fed from the FOH up in the organ loft. Are we picking up noise somewhere along the way? SOLUTION: The stage and the main equipment location in the organ loft are probably not on the same circuit. This is causing two problems; (1) with tri-phase power the two locations are not on the same phase meaning they are 120 degrees out of phase with each other and (2) they are not sharing the same ground reference. Solutions are numerous and ranging from a few hundred dollars to several thousand. The ideal solution would be to have an electrician add a dedicated circuit on the stage for the monitors that originates from the same electrical panel as the power for […] […]

    Pingback by Powered stage monitors make me buzz… | March 4, 2008 | Reply

  2. […] gain11 wrote an interesting post today onHere’s a quick excerptPROBLEM:75We75are75using75powered75stage75monitors75and75we75are75experiencing75a75loud75buzz.7575We’ve75switched75cables75and75speakers75to75no75avail.7575The75monitors75are75fed75from75the75FOH75up75in75the75organ75loft.7575Are75we75picking75up75noise75somewhere75along75the75way? SOLUTION:7575The75stage75and75the75main75equipment75location75in75the75organ75loft75are75probably75not75on75the75same75circuit.7575This75is75causing75two75problems;75(1)75with75tri-phase75power75the75two75locations75are75not75on75the75same75phase75meaning75they75are7512075degrees75out75of75phase75with75each75other75and75(2)75they75are75not75sharing75the75same75ground75reference.7575Solutions75are75numerous75and75ranging75from75a75few75hundred75dollars75to75several75thousand.7575The75ideal75solution75would75be75to75have75an75electrician75add75a75dedicated75circuit75on75the75stage75for75the75monitors75that75originates75from75the75same75electrical75panel75as75the75power75for75[…] […]

    Pingback by Gearfire.com » Blog Archive » Powered stage monitors make me buzz… | March 4, 2008 | Reply


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