Skidmore College
Amplitude Envelope

Amplitude Envelope Control In Bessie


This animated graphic envelope display is modeled after the old analog synth concept of ADSR (Attack, Decay, Sustain and Release).

The only new addition is "Dur", which is explained below.

By moving the sliders on this window, you can control the "envelope" of the sound.

Each slider controls one aspect of the envelope:

Att = Attack time of the sound in seconds: the time it takes for the sound to go from zero amplitude to maximum amplitude (1 is the the maximum value in this case).

Dec = The time (in seconds) that it takes the sound to drop from a maximum attack peak of 1 (being the max for the computer digital audio) to the level at which the sound will be sustained.

SLv = the level (between 0 and 1) that the sound will be sustained at AFTER the initial Decay. This Sustain level starts after Att + Dec slider values.

Dur = Duration in seconds. This duration begins after Att + Dec, so that the ACTUAL duration of the notee will = Att + Dec + Dur + Rel

Rel = The time (in seconds) that it takes to drop from the sustain level to 0. Bessiesimply adds this time to the previous values for Att, Dec and Dur. if you are using a MIDI keyboard for input (in a future release of this program) then this Release time begins once you let the key up (a key up message is sent to the program).


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