Gain

Gain is the amount by which an incoming signal is boosted, most importantly at the input of an audio interface or mixer, where a 'gain' or 'trim' knob sets how strongly a microphone or instrument signal is amplified before recording. Setting gain correctly is a fundamental recording skill: too little leaves the signal weak and noisy, while too much pushes it into distortion. Gain is often confused with volume, but they work at different stages — gain controls the strength of a signal coming in, whereas volume usually controls the level going out. Getting healthy gain levels at the source is the foundation of a clean recording.