Moog Subharmonicon Semi-Modular Polyrhythmic Analog Synthesizer - Manual (Page 22)

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The combined output signal from the mixer is internally wired to the input of the filter. Subharmonicon
relies on a Voltage Controlled Filter (VCF) to dynamically shape the timbre of a sound by selectively
removing frequencies above the Filter’s Cutoff Frequency. This low-pass filter is of the famous Moog
ladder type.
NOTE: Technically, this is a four-pole low-pass ladder filter providing 24 dB of attenuation per octave above the
Cutoff Frequency.
CUTOFF
This knob sets the Cutoff Frequency for the Filter, from 20 Hz to 20k Hz.
Frequencies below the Cutoff Frequency will be allowed to pass; frequencies
above the Cutoff Frequency will be attenuated at a rate of 24 dB per octave.
Turning the CUTOFF knob clockwise opens the filter by raising the Cutoff
Frequency, resulting in a brighter and more articulate sound.
Turning the
CUTOFF knob counter-clockwise closes the filter by lowering the
Cutoff Frequency, resulting in a thicker or darker sound.
RESONANCE
Resonance allows a certain amount of signal from the filter’s output to be
routed back to the filter’s input. This action gives added sonic emphasis via
a resonant peak that occurs at the Filter Cutoff Frequency.
Turn the RESONANCE knob clockwise to increase the level of this resonant
peak. Turn the RESONANCE knob counter-clockwise to decrease the level
of this resonant peak. Pushing the RESONANCE level to its maximum and
lowering the CUTOFF value can cause the filter to self-oscillate.
THE AMPLIFIER (VCA)
Before the sound leaves your Subharmonicon, it passes through the Voltage Controlled Amplifier to
attain the desired level. It is here that the Subharmonicon volume can be controlled.
VOLUME
The output level of the AUDIO OUT / jack is controlled via this knob.
Rotating this knob clockwise increases the Volume, rotating this knob counter-
clockwise decreases the Volume.
THE FILTER