Sound Performance Lab 9842 - Manual (Page 8)

Transient Designer
8
The SUSTAIN control circuitry
The SUSTAIN control circuitry includes two further envelope
generators. The envelope follower Env 3 (Diagram 4), again
follows the shape of the original curve.
For a longer period the envelope generator Env 4 (Diagram 4)
holds the sustain level according to the peak level and the VCA
control voltage is generated by the difference between Env 3
(Diagram 4) and Env 4 (Diagram 5: hatched area).
The sustain is extended at positive settings and shortened at
negative settings.
Diagram 3
illustrates the shapes of the
processed curves with
maximum and minimum
attack, compared to the
original curve from
Diagram 1.
Diagram 4
illustrates the original curve
and both envelopes generated
for processing the sustain
period.The envelope follower
Env 3 corresponds to the
original curve.The sustain of
Env 2 is extended.
Diagram 5
illustrates the difference
between Env 4 and Env 3. It
determines the VCA control
voltage.
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