FILTER 8
MULTIMODE FILTER/8-PHASE OSCILLATOR
2
CONTROLS & CONNECTIONS
1 FREQUENCY RANGE SWITCH
This switch determines over which frequency
range Filter 8 will operate: low frequency (slew
modifier/VCLFO) or audio frequency (VCF/VCO).
2 COARSE AND FINE FREQUENCY KNOBS
The filter/oscillator frequency is determined by
these knobs. In standard audio mode, with the
fine knob centred, the coarse knob has a range
of 22 Hz to 22 kHz. The fine knob’s range is 5 % of
the coarse knob (6 semitones in audio mode).
In low frequency mode, the total range is
2.8 mHz (a period of 6 minutes) to 180 Hz, with
1 Hz when both knobs are centred.
3 RESONANCE KNOB
The resonance knob controls a feedback path
from the filter output back to the input, causing
the filter frequency to be emphasised. Filter 8’s
design includes an innovative resonance circuit:
by increasing this parameter, all outputs will start
to resonate at the filter frequency, without any
low frequency response loss.
At higher feedback levels, self-oscillation will be
achieved, turning the module into an excellent
8-phase sine wave VC(LF)O.
4 VOLT PER OCTAVE FM INPUT
This input is used to modulate the frequency in
an exponential fashion, with a standard 1 volt per
octave response. This enables accurate audio
pitch in filter or oscillator mode. In the low range,
the sensitivity is increased to approximately 0.66
volt per octave.
5 EXPONENTIAL FM INPUT AND KNOB
This second exponential FM input includes a
polariser knob to set the modulation depth, with
0 in the centre, +1 volt per octave maximum and
−1 volt per octave minimum in audio mode. In
low mode, the sensitivity is increased to
approximately 0.66 volt per octave.
