Loudness Contour - Moog Minimoog Operation Manual

loudness contour

The volume of the audio signal which passes through the Modifiers section of the Mini Moog
is contoured by the Loudness Contour controls. These controls are connected to a contour
generator which supplies a control signal to the amplifier. Like the filter contour signal, the
loudness contour signal is composed of three segments − initial rise, decay, and sustain level.
Each time a key is struck, the contour generator is activated, and a note is shaped according
to the settings of the contour controls.
9. The ATTACK TIME control (23) determines the duration of the initial rise in volume to a
peak. Turn off the Noise Source (F) and turn on Oscillator 1 (C). Move control (23)
back and forth while repeatedly pressing down a key. Notice the different qualities which
a note takes on as a sharp attack becomes a slow crescendo.
10. The DECAY TIME control (24) determines the duration of the drop in volume from the
initial peak to the sustain level. The decay can be sharp or gradual.
11. The SUSTAIN LEVEL control (25) determines the volume level at which the contour
levels off after attack and decay. Set at 0, no sustain level is heard. Set at 5, the contour
diminishes to a low volume. Set at 10, no drop in volume is heard after the initial peak is
reached.
12. Finally, a DECAY switch (S) to the left of the keyboard allows the sound to fade out at
the decay time set by control (24), rather than immediately upon release of a key. This
final decay then, takes effect after the sustain level segment of the contour. To review the
phases of the overall loudness contour: a key is first pressed down. This produces an ini-
tial rise in volume, a decay, and a leveling off. The key is then lifted, and the sound is ei-
ther cut off immediately, or if the DECAY switch is on, fades at the rate set by control
(24). Turning on the DECAY switch can impart a life-like quality to notes which seem to
terminate too abruptly.
13. For sustained sounds and textures, a SHORTING PLUG is provided with the Mini Moog.
If this plug is inserted in the TRIGGER INPUT jack at the rear of the instrument, the fil-
ter and loudness contours will be triggered and remain at the sustain level. The mixer
output will then be amplified at a sustained volume whether or not a key is held down.
The keyboard will continue to provide a control signal for determining the oscillators'
pitches and the filter's cutoff frequency, according to the settings of switches (B), (K),
and (L).