Dynamic range compression (DRC) or simply compression reduces the volume of loud sounds or amplifies quiet sounds by narrowing or “compressing” an audio signal’s dynamic range. Compression is commonly used in sound recording and reproduction and broadcasting and on instrument amplifiers. Audio compression reduces loud sounds which are above a certain threshold while quiet sounds remain unaffected. The dedicated electronic hardware unit or audio software used to apply compression is called a compressor. In recorded and live music, compression parameters may be adjusted by an audio engineer to change the way the effect sounds.
Common names: audio compressor, automatic gain control, volume normalization, sound normalizer, loudness equalization, loudness equalizer