Dynamic range compression

Dynamic range compression (DRC) or simply compression, is an audio signal processing operation that reduces the volume of loud sounds or amplifies quiet sounds, thus reducing or compressing an audio signal's dynamic range. Compression is commonly used in sound recording and reproduction, broadcasting, live sound reinforcement and some instrument amplifiers.

A dedicated electronic hardware unit or audio software that applies compression is called a compressor. In the 2000s, compressors became available as software plugins that run in digital audio workstation software. In recorded and live music, compression parameters may be adjusted to change the way they affect sounds. Compression and limiting are identical in process but different in degree and perceived effect. A limiter is a compressor with a high ratio and, generally, a short attack time.

Compression is used to improve performance and clarity in public address systems, as an effect and to improve consistency in mixing and mastering. It is used on voice to reduce sibilance and in broadcasting and advertising specifically to make an audio program stand out. It is an integral technology in some noise reduction systems.