A.D.S.R. – Attack, Decay, Sustain, Release envelope commonly used to shape a wave form
ADSR – Attack, Decay, Sustain and Release are the four stages of an envelope that describe the shape of a sound over time.
- Attack represents the time the sound takes to rise from an initial value of zero to its maximum level.
- Decay is the time for the initial falling off to the sustain level.
- Sustain is the time during which it remains at this level.
- Release is the time it takes to move from the sustain to its final level. Release typically begins when a note is let up.
In most sound generators, the time and the value reached are programmable. The Attack, Decay, and Release parameters are rate or time controls. Sustain is a level. When a key is pressed, the envelope generator will begin to rise to its full level at the rate set by the attack parameter, upon reaching peak level it will begin to fall at the rate set by the decay parameter to the level set by the sustain control. The envelope will remain at the sustain level as long as the key is held down. When a key is released, it will return to zero at the rate set by the release parameter.
Demonstration Part A:
Demonstration Part B: