Envelope

EG, ENV, Envelope

A dynamic Module in Synthesizers to form a continious movement, applied to an amplifier (VCA) the envelope can change the sounds contour (amplitude in this case) and makes it sound "percussive" or "with a long fade-in and fade-out" to swell like water on a beach.

the Standard Envelope Form is ADSR, which start with Attack Time (A) from Minimum Level to Maximum, falls back to Sustain Level (S) with Decay (D) time. After key release with Release time (R) the signal will go back to 0 (if Sustain Level was 0 nothing happens after Decay time has passed).

image http://www.sequencer.de/pix/synthaudio_pics/adsr.gif

Envelope ist das engl. Wort für Hüllkurve.