ADSR Envelope

The ADSR envelope is the most fundamental modulation shape in synthesis. Attack controls how quickly a sound reaches its peak level after a note is triggered — fast attacks create percussive hits, slow attacks create swelling pads. Decay determines how quickly the sound drops from its peak to the sustain level. Sustain sets the steady-state level held while the note is pressed. Release controls the fade-out time after the note is released. ADSR envelopes can control volume (amplitude envelope), filter cutoff (filter envelope), pitch, and virtually any other parameter. Understanding ADSR is essential for shaping the character and feel of every sound you design.