In audio, bleed is the leakage of one audio source’s output into another audio source’s input. This can happen onstage, such as a drum or cymbal’s sound bleeding into a guitar amp mic, or in the studio, such as the output from a singer’s headphones leaking into the vocal mic.
Some solutions to reduce bleed include: mic selection and placement – using a cardioid or supercardioid mic on a source to reject signals from other directions; use of noise gates to attenuate mic sensitivity so they don’t pick up outside noise; and optimizing the gain stage of your mixer and peripherals to achieve an ideal signal-to-noise level.