A

David

Darling

envelope

An envelope is the rise and fall in volume or amplitude of a sound or note over time. For example, in terms of volume, a cymbal crash has a fast attack and a long, slow decay. Typical synthesizer envelope controls give the user control over the following four stages: attack, decay, sustain, and release (see ADSR).

 

An envelope generator is a device, circuit, or digital algorithm that creates an ADSR envelope.