Studio Electronics ATC-1X - Manual (Page 14)

The filter envelope shapes the timbre and
overtone content of the audio signal as it passes
through the modifying circuitry from the mixer.
This envelope or "contour" generator is used to
dynamically move the cutoff frequency. It works
as such: each time a key is depressed an
envelope or "contour” generator attached to the
filter's cutoff frequency is actuated, and sends a
control signal to the filter. The control signal
rises at one rate, falls at a second rate, levels off
at a certain level, and then finally falls off at a
third rate. These four parameters and their effect
upon the cutoff frequency are explained below.
What the Switch pads do:
Selects the attack time. The attack time determines the initial segment of the
envelope. The frequency at which the contour begins is determined by the filter
frequency setting, while the peak, which it reaches, is determined by the filter
frequency and Envelope 1 amount settings combined. Incrementing the value
from 0
0 -- 127 127 will result in the brightness of the sound increasing sharply at first,
and then more gradually as the attack time lengthens.
Selects the decay time. The decay time determines the duration of the second
segment of the envelope, i.e., the fall from the attack peak to the sustain level.
While repeatedly depressing a key and incrementing the value from 0
0 -- 127 127 you
will at first hear the brightness drop sharply after the initial attack; the drop will
become more gradual as the decay time lengthens.
Selects the sustain level. The sustain level determines the filter frequency at
which the envelope "levels off" after the initial rise and fall. The frequency of the
sustain level can be as high as the initial peak, in which case there is no decay
after the initial rise, or it can be as low as the frequency at which the envelope
contour began.
Selects the release time and is the fourth and final stage of the envelope
contour. Finally, after the initial rise and fall of the attack and decay times to the
sustain level, the release time takes effect after the sustain level segment, when
the played key or note is lifted. The frequency at which the sustain level is set,
falls to the initial filter cutoff frequency level at the rate set by the release time.
ENVELOPES continued on next page.