Compression

A compressor automatically reduces the volume of audio that exceeds a set threshold. Key parameters: threshold (level where compression starts), ratio (how much gain reduction is applied — 4:1 means 4dB over threshold becomes 1dB), attack (how quickly the compressor reacts), release (how quickly it stops compressing), and makeup gain (compensates for volume lost during compression). Gentle compression (2:1-4:1) smooths dynamics. Heavy compression (10:1+) creates pumping effects. Sidechain compression — triggered by an external signal like a kick drum — is the foundation of the 'pumping' effect in EDM. Compression is essential for professional-sounding mixes.