wmd-c4rbn

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.

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