vimsynth/modules/vcf

modules/processors/VCF

VCF

Resonant filter, state-variable. Three outputs at once: lowpass (dark, the usual choice), bandpass (hollow, good for rain and voice-like sounds), highpass (thin). The workhorse of subtractive synthesis.

The VCF card as vimsynth draws it: its title bar, 3 knobs, 4 inputs down the left edge and 6 outputs down the right
VCF on an empty rack — 32×16 cells, knobs at their defaults. Press a in the app and pick VCF to get this card.

inputs

Down the left edge of the card, top to bottom.

laudio
The signal to filter, left.
raudio
The right side. Normals from l, so ONE cable in is the mono filter this always was — patch both and it stays stereo all the way through.
cutoffcv
Moves the cutoff, in OCTAVES, scaled by the cv amt knob. An ADSR here is the classic filter sweep.
rescv
Modulates the resonance.

outputs

Down the right edge, in the same order.

lp laudio
Lowpass: keeps the lows. THE usual choice — dark, round, the sound of subtractive synthesis.
lp raudio
Lowpass: keeps the lows. THE usual choice — dark, round, the sound of subtractive synthesis. The right side.
bp laudio
Bandpass: keeps a band. Hollow, nasal, vocal. Noise through a swept bandpass is wind, rain and surf.
bp raudio
Bandpass: keeps a band. Hollow, nasal, vocal. Noise through a swept bandpass is wind, rain and surf. The right side.
hp laudio
Highpass: keeps the highs. Thin, brittle; also how you take the mud out of a layer.
hp raudio
Highpass: keeps the highs. Thin, brittle; also how you take the mud out of a layer. The right side.

knobs

Left to right across the face — the dials in the picture.

cutoff20 … 18000 hz= 1200 hz
The cutoff. Low is dark and muffled; high is open and bright. THE most-modulated knob in subtractive synthesis.
res0 … 1= 0.2
Resonance. Emphasises the cutoff; high values whistle and, at the top, self-oscillate. Keep it LOW for anything described as soft, warm or soothing.
cv amt0 … 6= 2
How many octaves the cutoff input moves it. This is the depth control for a filter sweep.

more

The full reference — every parameter curve, the patching notes and the worked examples — lives in the manual: docs.vimsynth.com/modules/vcf. In the app itself, :help VCF opens the same page without leaving the rack.