Leakage has also been called “bleed” or “spill,” and is the overlap of sound from one instrument into another instruments microphone. For example, if you’re miking drums and guitar in the same room with each having their own microphones and the guitar is picked up in the background with the drums mic’s this would be “leakage.”

• Mic as close as possible with directional microphones.
• If recording with multi-track recorders, if possible record each instrument one at a time. This is called “overdubbing.”
• Try using direct boxes or plugging instruments in “directly” with cables. (Bass & electric keyboards work well this way)
• Use a studio or room with dead acoustics.
• Always aim the null of the polar pattern at the offending noise source. For example, if recording a snare drum aim the null of the mic at the high-hat to reduce high-hat leakage into the snare mic.
• If possible try using baffles or recording booths or cabinets with doors (closets make great recording booths). Or lets say put the guitar amp in a totally different room as the other interments.