Expander

A dynamics processor that widens the difference between loud and quiet signals, pushing levels down once they fall below a threshold.

It is the mirror of a compressor, and in its most aggressive form it becomes a noise gate, cutting the signal entirely when nothing is being played. Used gently, an expander restores some of the natural dynamics a compressed signal has lost, or tames a background noise floor by attenuating it while louder passages pass untouched. A related upward expander works above the threshold, making loud parts louder instead of quiet parts quieter.

Example: a downward expander with a modest ratio cleanly removes the hiss between phrases in a heavily overdriven signal without the abrupt chop of a hard gate.

Expander

See also