Colloquially, AMPLIFICATION. Technically, the ratio of the output of a system such as an AMPLIFIER to its input. It may be expressed as a simple arithmetical ratio or in DECIBELs.
Determining the record or playback levels on a tape recorder is often called gain adjustment.
See: FADER, LIMITER, PEAK CLIPPING, POTENTIOMETER. Compare: DYNAMIC RANGE, SIGNAL-TO-NOISE RATIO, VU METER.