11.3

PANGEA WORLD INSTRUMENTS400
The Amp Envelope is a standard ADSR envelope which controls the amplitude of the signal over time. The picture
below shows the various stages of the ADSR envelope:
The ADSR envelope stages.
• A(ttack)
When you play a note on your keyboard, the envelope is triggered. This means it starts rising from zero to the value
set with the Master Volume knob. How long this should take, depends on the Attack setting. If the Attack is set to
“0”, the Volume value is reached instantly. If the Attack value is raised, it will take longer time before the Master
Volume value is reached.
• D(ecay)
After the Master Volume value has been reached, the level starts to drop. How long this should take is governed
by the Decay parameter.
If you want to emulate the volume envelope of a note played on a piano for example, the Attack should be set to
“0”, the Decay parameter should be set to a medium value and the Sustain level should be set to “0”, so that the
volume gradually decreases down to silence, even if you keep holding the key down. Should you want the decay to
drop to some other value than zero, you raise the Sustain parameter.
•S(ustain)
The Sustain parameter determines the level the envelope should rest at, after the Decay stage. If you set Sustain
to full level, the Decay setting is of no importance since the volume of the sound is never lowered.
If you want to emulate the volume envelope of an organ, you theoretically only really need to use the Sustain pa-
rameter set to full level, as a basic organ volume envelope instantly goes to the maximum level (Attack “0”) and
stays there (Decay “0”), until the key is released and the sound instantly stops (Release “0”).
But often a combination of Decay and Sustain is used to generate envelopes that rise up to the Volume value, then
gradually decreases to finally land to rest on a level somewhere in-between zero and the Master Volume value.
Note that Sustain represents a level, whereas the other envelope parameters represent times.
•R(elease)
The Release parameter works just like the Decay parameter, except it determines the time it takes for the volume
to drop back to zero after you release the key.
Attack
(time)
Decay
(time)
Sustain
(level)
Release
(time)
Time
Level
Key Down Key Up
Volume
(level)