What is an Envelope?

An Envelope is a control mechanism in sound synthesis that shapes how a sound changes over time. It is known for defining the evolution of a sound’s amplitude or other parameters.

The concept typically includes stages such as attack, decay, sustain, and release (ADSR), which determine how quickly a sound starts, how it settles, how long it is held, and how it fades out.

An Envelope emphasizes dynamics and expression, allowing sounds to be shaped from sharp and percussive to smooth and sustained.

It can be applied not only to volume but also to parameters like filter cutoff, pitch, or modulation depth.

Today, Envelopes are essential in synthesizers and audio production, valued for their role in shaping the character, articulation, and behavior of sound over time.