Dynamics Control

Attack and release set the timing of the processor. A fast attack, from a fraction of a millisecond to a few milliseconds, catches transients immediately; set too fast on a snare drum, it can dull the initial crack. A slower attack lets the initial transient through and then acts on the body of the sound. Release sets how quickly the gain recovers once the signal falls back: a release that is too fast produces audible pumping and breathing between notes, and one that is too slow keeps the gain reduced and dulls the following notes. The knee sets how gradually compression begins around the threshold, a soft knee being more progressive than a hard knee. Makeup gain restores the overall level lost to gain reduction.

A few decibels of gain reduction usually gives control without audible side effects. Heavy settings flatten the dynamics of a performance, and artifacts such as pumping and dulled transients become audible in the mix.