Noise in Audio Systems allegedly Caused by Lighting
The problem of annoying hums and buzzes, particularly of the 60Hz variety, is very common
Systems and often immediately attributed to the Lighting System. While this is one
possibility, more often than not, Iíve found that itís not really Lightingís fault. Weíre not here to assign
blame and point
fingers, merely to fix the problem.
Somehow, errant RFI
/EMF signals are getting into the audio system and being amplified. Audioís
of defense against this is a good electrical earth ground
on each and every piece of
unit, especially including the backline
. Many times Iíve had a system sounding perfect until the
band arrives and plugs in!
Step One. To check that a good ground is present and all outlets/electrical devices are wired
properly, one cannot do without one of these:
(picture from Amprobe PY-3 110V AC Receptacle Tester
An outlet tester
, available at any hardware store, even in the electrical department at Wal-Mart
and similar, or (my personal favorite and likely the most frugal) Harbor Freight Tools for $2.99.
Follow the instructions on the device. If you donít get two yellow (or sometimes two green, depending on the specific model) lights lit, youíve got a
problem. Consult a licensed electrician. Use this device every single place thereís an Edison
-blade, U-ground; NEMA
. An adjunct to Murphyís Law says the one you forget to test WILL be the culprit.
Once youíre confident that all outlets are wired properly with all earth grounds intact, if
the problem persists, itís time to move to Step Two.
This is a tough one, but I promise it will prove rewarding. Test each and every one of the cables used in the entire sound system,
especially the personal ones of the bass, guitar, and keyboard players. Remember, ďOne bad apple can spoil the
whole bunch of girls,Ē as Donny Osmond reminded us many moons ago.
(picture from Galaxy Audio Cable Tester | GuitarCenter
a cable tester, available at Guitar Center and other fine establishments, costs around $60. I
actually prefer this one, the Whirlwind TESTER (catchy name, huh?),
(picture from TESTER - Catalog - Whirlwind
But it costs more and does less, and doesnít seem to be listed on Guitar Centerís website. If
youíre really strapped for cash, neither of the two testers above do anything a Digital Multi-
), set on Continuity
or more specifically, Resistance (ohms Ω) canít do, but the
multi-meter requires a greater knowledge of electricity and can be dangerous in the wrong
hands. ELECTRICITY KILLS. WHEN IN DOUBT, CONSULT A QUALIFIED
Again, once you have a tester, test every cable in the building. While watching the indicator
lights be sure to twist, wiggle and abuse the wires where they enter the connector
If you donít, the performers and musicians certainly will.
Letís stop here for now. Go back and complete Steps One and Two. Let me
youíre done, and we'll proceed with Steps Three through Nine-Hundred Sixty-Seven.
For further reading, I highly recommend a paper by Middle Atlantic, available for download in PDF form at Middle Atlantic Products - White Paper - Integrating Electronic Equipment and Power into Rack Enclosures