Moog Minimoog Operation Manual page 11

TIME control from left to right. You will hear the brightness of the note increase sharply
at first, and then more gradually as the attack time increases.
4. The DECAY TIME control (21) determines the duration of the second segment of the
contour, the fall from the initial peak to the sustain level. The range of this control is
about the same as that of the previous control. Set the DECAY TIME control at various
levels moving slowly from left to right, while repeatedly depressing a key. At first you
will hear the brightness drop sharply after the initial attack; the drop will become more
gradual as the decay time increases.
5. The SUSTAIN LEVEL control (22) determines the frequency at which the contour 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 contour began. To hear this most effectively, set the filter controls
for CUTOFF FREQUENCY of -2, high AMOUNT OF CONTOUR, and medium DE-
CAY TIME. Now repeatedly depress and hold down a key while setting control (22) at
various levels. Set at 0, the contour decay effectively wipes out the signal; set in the
middle, the brightness levels off at a frequency somewhere below the initial peak, and set
at 10, the brightness of the note rises to an initial peak and remains there.
6. The EMPHASIS control (18) introduces a sharp resonance in the response of the filter at
the cutoff frequency. The effect of this control can be heard very easily. To observe it,
turn the AMOUNT OF CONTOUR fully to the left to shut off the contour signal, and turn
the EMPHASIS control to 7. Depress a key, and turn the CUTOFF FREQUENCY con-
trol slowly throughout its range. You should hear the individual overtones of the oscilla-
tor waveform being emphasized one by one as the resonance passes over them. Now set
the CUTOFF FREQUENCY to about -2, turn the AMOUNT OF CONTOUR all the way
up, and repeatedly hold down a key while changing the settings of controls (20), (21), and
(22). Notice how the filter contour is now heard as a sweep of the overtone series when
(20) and (21) are turned up to about 7 seconds and (22) is set low.
We have seen how the filter cutoff frequency may be controlled manually and using the
filter contour controls. These are in addition to other means of controlling the filter.
7. The MODULATION MIX (3) of Oscillator 3 and the Noise Source may be used to
modulate the filter cutoff frequency in exactly the same way it is employed to modulate
the pitches of the oscillators. To direct the Modulation Mix to the filter, the FILTER
MODULATION switch (J) must be turned on. Then the MODULATION wheel (29) can
be moved forward with the left hand to introduce the desired amount of modulation as the
keyboard is played with the right hand. To test this, turn (18) and (19) all the way down
and set (17) to about 1 or 2. Make sure that the Oscillator Modulation switch (A) and Osc.
3 Control Switch (B) are off, and turn on switch (J). Set the MODULATION MIX con-
trol all the way to the left. Oscillator 3's RANGE switch should be set to LO. You will
observe as you did when applying the Modulation Mix to the oscillators that the modula-
tion contour depends on the settings of the FREQUENCY and WAVEFORM controls of
Oscillator 3. A more complex sound can be made by adding the effects of controls (18)
and (19).
8. The two KEYBOARD CONTROL switches (K) and (L) apply the control signal pro-
duced by the keyboard to move the filter cutoff frequency up and down. This is impor-
tant in setting up a sound, for if there is no keyboard control of the filter, the higher notes
on the keyboard will sound duller than the lower ones, having more of their overtones