When my band rehearses, the cymbals are always leaking into the vocal microphones. How can we stop this from happening?
Ah, Cymbals—the bane of many a sound engineer’s existence. From rehearsal rooms to large arenas, cymbal leakage in vocal mikes causes problems. Cymbals occupy the same frequency range as the human voice, and cymbals are pretty loud. Think about it: a cymbal on a stand is approximately the same height as a vocal mic on a stand. How do we cope with this problem? In a rehearsal situation, try turning the vocal mikes so that the drums and cymbals are not directly behind them. Most vocal microphones have a cardioid response pattern (see diagram). Cardioid mikes pick up sound from the front of the mic and reject sound from the rear. So if your singer(s) are facing the drummer, the vocal mikes will be rejecting the direction that the drums are in, and the leakage problem will be reduced. Super cardioid microphones like those made by Electro-Voice and Audix have even tighter patterns with more rejection from the sides and back.
Mic placement is not the only answer. You can also try placing baffles in front of the drums to block the sound. If your rehearsal space is very live (hard surfaced walls), you may want to deaden the walls with some foam sheets or packing blankets. Hard surfaces cause sound to bounce around the room and get into the vocal mikes.