From inSync reader Mike S, “Being a studio engineer one problem I consistently encounter, and have yet to figure the cause or solution, is the noise and hum that come from electric guitar pickups. If I mic a guitar amplifier in an isolated sound booth, or record direct from a guitar pre-amp, or direct to console, I get a hum from the pick-ups, which can change dramatically if the guitar player moves the angle and/or direction of the guitar even an inch or two. Is there anything out there, that can eliminate this completely?”
A typical guitar pickup will behave much like a transformer (see WFTD above “Transformer“). In the case of buzzing guitars the pickup is behaving like a transformer secondary and picking up EMI (see WFTD “EMI“) from the surrounding equipment. Once this hum or buzz is induced into the pickup and passed on to the downstream electronics of the guitar there is no way to really remove it without sophisticated signal processing specifically designed for hum removal. The best solution is to try to stop it before it starts. One solution, adopted years ago, is the use of humbucking guitar pickups. These employ two magnets and two coils of wire that are wound backwards to each other and are thus out of phase. The hum is induced into both coils, but the output is mostly (though not completely) canceled because the coils are wired out of phase from one another. Humbucking pickups generally produce far less hum than single coil designs.
Humbucking guitar pickups have been in use for years and are still very popular today. There are a gazillion different types that all have different sonic characteristics or offer some other features such as coil taps and more. Almost all of them, however, tend to sound different than single true coil pickups so some artists still prefer to use the original old single coil type. In those cases there isn’t much you can do other than to try to remove the source of the EMI or position the guitar in such a way that the effect is minimized. This one kind of reminds me of the answer for, “How do I keep my stage monitors from feeding back?” You can start by not aiming a speaker at a microphone! There’s just no perfect solution.
If anyone out there has any unusual tricks or tips for either problem let us know.