(compMus1) Basic Synthesis Controls – Envelopes

In general terms, an envelope is a function that changes over time. Typically, an envelope is a multi-segment function for controlling a synthesis parameter. Amplitude envelopes are most common, but any parameter of synthesis (pitch, filter frequency, lfo rate, etc.) can be controlled by an envelope.

The most typical type of envelope used is the ADSR: Attack, Decay, Sustain, Release.

• Attack time: the time it takes from zero value to maximum value.
• Decay time: the initial decay from the maximum attack level to the sustain level.
• Sustain level: the sustain level occurs after the attack and initial decay.
• Release time: the time it takes to go from the sustain level to zero.