MULTIMODE FILTER/8-PHASE
7
PATCH IDEAS
RESONATING ENVELOPES
Add interest to your envelopes by processing
them through Filter 8. If the envelope has an
amplitude of above +5 V, attenuate it first and
then patch it to a Filter 8 signal input. The
processed envelope is available at the LP1 output.
With the low frequency range active, you can
slew the envelope and introduce some
resonance to add ‘bounce’ to transients. Switch
to the audio range to superimpose an audio-
frequency component to the low frequency
envelope for a unique combined modulation
signal. Don’t forget to try out the other filter
outputs as well!
HOLD MODULATION
Using the hold input for audio-frequency
modulation creates unique tones, somewhere
between linear FM and standard oscillator sync.
With Filter 8 in oscillator mode (no input, audio
range, maximum resonance), apply an audio
signal to the hold input and engage the switch.
Tune Filter 8 and the modulation source to a just
interval, and apply volt per octave FM to both to
create ‘bell’ or ‘synthetic bass’ tones reminiscent
of vintage digital FM synthesisers.
If the hold signal source is a pulse wave, you can
additionally modulate the pulsewidth to control
the ‘depth’ of the hold effect.
RESPONSE BLENDING
Filter 8’s multimode outputs are created using
pole mixing, combining the input and lowpass
outputs signals in precise ratios and polarities.
This technique can be recreated externally: using
a mixer module, add together various outputs to
experiment with creating your own responses.
Use a voltage controlled mixer and apply
different modulations to the channels for
dramatic effect.
FEEDBACK DRIVE
Many synthesiser filters include an input
overdrive circuit. While this is not present on
Filter 8, the sound of an overdriven filter can still
be easily created, and with much expanded
sonic possibilities, using feedback patching.
With Filter 8 filtering an external audio signal,
send the LP4 output to an attenuator, and then
back into the spare input socket. The attenuator
controls the amount of ‘drive’.
Experiment with using different responses for
audio output and feedback. Replace the
attenuator by a VCA for voltage control over the
tone.
SAW WAVE OSCILLATOR
Another application for feedback is changing the
waveshape in oscillator mode. Patch the BP4
output to the exponential FM input. The EFM
depth now determines the waveshape. At
maximum modulation depth, the LP2 and BB+N
output signals will be near-perfect saw/ramp
waves.
The other outputs provide additional interesting
waveshapes, ranging from rectified sine waves to
curved saws. Note that the feedback depth also
affects the volt per octave pitch tracking.
