ADSR Envelope

 

ADSR is an acronym that stands for Attack, Decay, Sustain, Release and is a means to replicate those respective elements of a sound.

 

The envelope is a form of automation (automatic movement) built into synthesizers to control the value of a parameter (usually volume or filter cutoff frequency) over time. Envelopes are critical for giving synthesizers a more natural and interesting sound, as they can be used to simulate the volume envelopes of a real instrument. However, envelopes are also great for creating special effects. The most common type of envelope is called ADSR (Attack, Decay, Sustain, Release), referring to the different functions of each part of the envelope.

 

ADSR Envelope elements:

• Attack - Attack determines the time it takes for the note to get to the maximum level.

• Decay - Decay determines the time it takes for the note to go from the maximum level to the sustain level (controlled by Sustain).

• Sustain - Sustain determines the level of the sound is played at while the note is held (after the other envelope states, Attack and Decay, have been completed).

• Release - Release determines the time it takes for the note to fall from the sustain level to zero (silence) level when it is released.