Moog System 15 Instruction Manual page 15

F. USE OF TWO ENVELOPE GENERATORS AND THE REVERSIBLE
ATTENUATOR
The Synthesizer 15 has two 911 ENVELOPE-GENERATORS. The voltage contour pro-
duced by a 911 may control the frequency (when patched to a 921), amplitude (when patched
to the 902), or filtering (when patched to the 904A) of an audio signal. With two envelope
voltages, it is possible to control two audio signals, or two aspects of a single audio signal.
1. Clear the instrument. Arrange all patchcords and controls as shown above.
2. Turn the 904A FIXED CONTROL VOLTAGE down to 3. Play the keyboard. The left 911
ENVELOPE GENERATOR is controlling the cutoff frequency of the LOWPASS FILTER.
Experiment with the settings of the 911 to observe the effect of contour shape on tone color.
3. While playing the keyboard, gradually turn the REVERSIBLE ATTENUATOR to 0. No-
tice that the action of the 911 is pulled at 0. Gradually turn the REVERSIBLE ATTENUA-
TOR from 0 to -6. Note that the voltage contour of the upper 911 is now inverted.
4. Turn down the FIXED CONTROL VOLTAGE on the 902. Play the keyboard. The right
911 ENVELOPE GENERATOR is controlling amplitude.
5. Experiment with the controls of both 911 ENVELOPE GENERATORS to observe the ef-
fects of different filtering and amplitude contours.
2
907A 995
0 0
8'
50
921A 921B 921B 923
MIXER REV
10
6
6
904A 902 902
921 911 911
CONTROLLERS TRUNK