attackdecaysustainrelease
Attack-decay-sustain-release (ADSR) envelope is a fundamental concept in subtractive synthesis and digital audio production. It describes the time-based shaping of a sound’s amplitude, and sometimes other parameters, in response to a note being played and released. The envelope has four stages: attack, decay, sustain, and release.
Attack is the time it takes for the sound to reach its maximum level after a key
ADSR envelopes are commonly used to control amplitude, but they can modulate other parameters such as filter