WMD C4RBN
Warm state-variable filter with saturation and wavefolding
4 HP Eurorack module
C4RBN is a 4/2-pole state-variable filter with wavefolding by WMD, featuring a novel input saturation circuit and the wavefolder from the classic SYNCHRODYNE. It offers warm, flexible timbral shaping across LP, BP, HP, and 4-pole outputs with self-oscillation, vactrol-style pinging, and deep harmonic coloring from saturation and folding.
Features
- 4/2-pole state-variable filter with LP, BP, HP, and 4P outputs
- First 2-pole filter provides simultaneous LP, BP, and HP outputs
- Second series 2-pole filter feeds the 4P output with selectable frequency response
- Output wavefolder on 4P output derived from WMD SYNCHRODYNE
- Novel input saturation circuit with 4 levels and analog CV control
- Self-oscillation above 3 o'clock on RES knob
- PING input generates fast-decay vactrol-emulating envelope
- FM input with inverting attenuator for exponential cutoff modulation
- V/OCT input calibrated for keytracking with temperature compensation
- Filter cutoff range 2.5Hz to 10kHz
- Warm environment stability improvements for live performance
- HP/BP/LP button cycles 4-pole response with audio-safe preview via LED
Controls & Jacks (18)
- FREQ — Sets the filter cutoff frequency manually, from very low (2.5Hz) up to 10kHz.
- FM — Inverting attenuator that scales the signal at the FM input jack. Controls how strongly the FM CV input modulates the filter cutoff. Exponen
- RES — Controls filter resonance. Higher settings emphasize frequencies around cutoff. Self-oscillates past 3 o'clock.
- HP LED — Indicates high-pass filter response mode selection.
- BP LED — Indicates band-pass filter response mode selection.
- FOLD LED — Lit when 4P output wavefolder is enabled.
- SAT LED — Indicates current input saturation level (4 levels).
- FOLD/SAT — Press to toggle 4P output wavefolder (FOLD LED indicates status). Hold to cycle through 4 levels of input saturation (SAT LED indicates leve
- SAT — Analog CV input for the input saturator. Offers greater control over saturation level.
- PING — Gate or trigger input that generates a fast decay envelope emulating vactrol response.
- FM Input — FM CV input for exponential control of filter cutoff frequency.
- RES CV — CV input for filter resonance control.
- IN — Audio input passes through the input saturator before entering the first 2-Pole filter.
- V/OCT — Calibrated exponential CV input for controlling filter cutoff in classic keytracking style.
- BP — Band-pass output of the first 2-Pole filter.
- HP — High-pass output of the filter.
- LP — Low-pass output of the first 2-Pole filter.
- 4P — Output of the 2nd series 2-Pole filter with selectable frequency response and output wavefolder.
How-To Guides
- Pure Sine from Self-Oscillation
- Vactrol Percussion via Ping
- Warm Saturated Bass Filter
- Wavefolded Lead Synth
- Animated Filter with FM Modulation
- Keyboard Tracking Filter
- Parallel Filter Textures
- Dynamic Saturation with CV
- Gentle EQ and Tone Shaping
- Generative Melodic Pinging
Explore the interactive C4RBN panel on BleepDex — tap any control to learn what it does.
