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LADDER FILTER

Moog-Style Ladder Filter

Download free Part of NULL JSFX 2.5: 113 plugins, free and open source (MIT). Easiest with NULL JSFX Hub.

Listen

The same music with the Warm Bass Lowpass preset and without the plugin. Switch while it plays.

Controls

Cutoff20 to 20000 Hz — Filter cutoff frequency
Resonance0 to 4 — Feedback around the ladder; high values approach self-oscillation (capped at 3.95)
Drive0 to 100% — Input gain into the saturating ladder for analog growl (level-compensated)
ModeLowpass / Highpass — Lowpass or Highpass 24 dB/oct response
Gain−12 to +12 dB — Output level

Best uses

Classic resonant synth filter sweeps
Warm, driven lowpass on drums and bass
Automated filter build-ups
Highpass sweeps with resonant peak
Taming harsh digital sources with analog character

Properties

Signal chain: Input → Drive → 4-Pole Zero-Delay-Feedback Ladder (24 dB/oct, tanh saturation in the loop) → LP / HP Output → Gain → Output. Stable and in tune up to 20 kHz at full resonance; stereo channels independent, zero latency.

Formats

JSFXJSFX for REAPER, with REAPER's own sliders
GFXJSFX GFX for REAPER, with its own interface
VST3VST3 for any DAW
CLAPCLAP for any DAW

Factory presets

Warm Bass Lowpass · Acid Squelch · Dark Drum Bus · Digital Tamer · Filter Build Start · Resonant HP Sweep · Thin Out Highpass

In the FX chains and Rack presets

Distorted Throw · Psychedelic Echo · Rhythm Engine

See every FX chain

Try it

Try it on orOS StudioAdd it to a track in your browser, with its own interface. Nothing to install.