Eurorack Reference / modules /wmd/c4rbn audit site v0.1 — milestone 3
wmd/c4rbn

C4RBN

WMD

4/2-pole state-variable filter with input saturation, output wavefolding, simultaneous 2-pole HP/BP/LP outputs, and a switchable 4-pole output (HP/LP/BP). Includes a ping circuit emulating vactrol response and temperature-compensated V/Oct tracking.295

Visualization filter_response

Capabilities 4

Input Saturationinput-saturation
295
Self-Oscillationself-oscillation
Filter self-oscillates when resonance is set above the 3 o'clock position.295
State-Variable Filterstate-variable-filter
4/2-pole SVF with simultaneous 2-pole HP/BP/LP outputs and a switchable 4-pole output (HP/LP/BP). Self-oscillates above 3 o'clock on the RES knob.295
Wavefolderwavefolder
Output wavefolder from the classic SYNCHRODYNE, applied to the 4-pole output. Toggled via the FOLD/SAT button.295

Jacks 9 — 5 in / 4 out

NameSignalVoltageDescription
Inputs (5)
FMcvExponential FM CV input for controlling filter cutoff. Scaled by the FM attenuverter knob.295
INaudio-10V to 10VAudio input; passes through the input saturator before entering the first 2-pole filter.295
PINGgateGate or trigger input that generates a fast decay envelope routed to cutoff, emulating the response of a vactrol for resonant pinged tones.295
SATcvAnalog CV input for the input saturator; offers greater control over the saturation level.295
V/OCTcvCalibrated exponential CV input for controlling filter cutoff in the classic keytracking style. Temperature compensated.295
Outputs (4)
2P BPaudio2-pole (12 dB/oct) band-pass output of the first state-variable filter stage. Available simultaneously with the 2P LP and 2P HP outputs — all three are taps off the same SVF core, independent of the HP/BP/LP switch that selects the 4P OUT response.295
2P HPaudio2-pole (12 dB/oct) high-pass output of the first state-variable filter stage. Available simultaneously with the 2P LP and 2P BP outputs — all three are taps off the same SVF core, independent of the HP/BP/LP switch that selects the 4P OUT response.295
2P LPaudio2-pole (12 dB/oct) low-pass output of the first state-variable filter stage. Available simultaneously with the 2P BP and 2P HP outputs — all three are taps off the same SVF core, independent of the HP/BP/LP switch that selects the 4P OUT response.295
4P OUTaudio4-pole output whose response (HP, LP, or BP) is selected via the HP/BP/LP panel button. Output wavefolder can be toggled on this output via the FOLD/SAT button.295

Parameters 5

NameTypeRangeBehavior
FMknobInverting attenuator that scales the FM input jack signal. Exponential response controlling filter cutoff.295
FOLD/SATbuttonPress to toggle the 4-pole output wavefolder (FOLD LED indicates enabled state). Hold to cycle through 4 levels of input saturation (SAT LED indicates current level).295
FREQknob2.5Hz – 10000HzManual filter cutoff frequency control, ranging from 2.5Hz to 10kHz.295
HP/BP/LPbuttonCycles through HP, BP, and LP responses for the 4-pole output. LED changes immediately; audio waits until selection is made. Holding the button delays the audio change until release.295
RESknobControls filter resonance. Self-oscillates above the 3 o'clock position.295

Firmware history 0 versions

No firmware history recorded.

References 2

  1. [295]
    C4RBN Manual v1.1manual
    verified 2026-05-10
  2. [296]
    WMD C4RBN product pageproduct_page
    verified 2026-05-10