====== envelopes ======

===== introduction =====

The envelope describes the shape of the change in amplitude over time.

===== text =====

definition and some history: https://en.wikipedia.org/wiki/Envelope_(music)

more detail about envelopes: https://www.pitchbends.com/posts/sound-envelopes-adsr

===== video =====

basic and great explanation with examples: https://www.youtube.com/watch?v=Q-ot9AaJx-Y