Effects

Distort

Five-mode distortion: tube-style soft clip, hard clip, Buchla-style wavefolder, octave-up rectifier, and bitcrusher.

What is a Distort?

Distortion is what happens when a signal is pushed past the limits of the system that's amplifying it. Drive a tube amp too hot and it compresses - peaks get squashed, harmonics multiply, the sound thickens and sustains. Drive a transistor circuit too hot and it clips - peaks square off, odd harmonics bloom, the sound bites. Drive a digital sample too hot and it wraps or *folds* depending on how the math handles overflow. Each kind of nonlinearity has a sound, and music history is built on those sounds.

Mathematically, distortion is nonlinear waveshaping: a function that maps every input sample to an output sample, but not as a straight line. A clean amplifier is y = x - output equals input. A soft clipper is y = tanh(x) - output approaches a limit smoothly. A hard clipper is y = clip(x, ±1) - output slams into a wall. A wavefolder is y = sin(πx) - output bends back on itself when the input exceeds the fold threshold. Each of these creates *new* harmonics that weren't in the input, which is why distortion changes the timbre, not just the loudness.

Modular synthesis has two great distortion lineages. East-coast: tube and transistor saturation, fuzz, full-wave rectification - the language of guitar pedals and analog studio gear. West-coast: Don Buchla's wavefolders, where overdriving a sine wave into a folding circuit generates harmonic-rich, almost-additive timbres - the Buchla 259's 'timbre' section is the textbook example. The Plaits 'fold' parameter is a direct descendant.

And then there's the digital-era addition: bitcrushing. Reduce the sample rate (creating aliasing) or reduce the bit depth (creating quantization noise) and you get the lo-fi, gritty, pixelated sound that defines a whole genre. Same idea as analog distortion - introduce a controlled error - but the artifacts are very different.

Our Distort

Five distinct distortion characters in one module: soft (tanh), hard (clip), fold (sine wavefolder), rect (octave-up rectifier), and crush (bitcrusher from 12-bit down to 2-bit). The hard-clip and bitcrush modes are 2x oversampled to keep alias artifacts under control - bitcrushing a clean signal generates lots of high-frequency content that needs to be band-limited or it folds back as garbage.

After the distortion stage, a post-distortion tone filter shapes the output. It's a one-pole crossfader: turn left for a darker lowpass character, center for neutral, turn right for a thinner highpass cut. This lets you tame harshness on hard-clip mode or brighten soft-clip warmth without reaching for a separate filter.

Drive has a CV input with an attenuverter, so envelope-modulated distortion swells are one cable away. Mix blends dry and wet for parallel-distortion patches - useful when you want crunch on the harmonics but a clean fundamental. 8 HP, 5 parameters, mode-selectable in real time. Pair with Filter or Ladder for proper subtractive grit.

In a patch

Distortion sits early in the chain, before filter and any time-based effect. The classic acid signal flow: VCO -> distortion -> ladder -> VCA. Distortion adds harmonics; the filter then carves them - that's where the squelchy, alive bass tones come from. Distortion *after* a filter still works, but you lose the carving step.

On bass, soft clip with low drive (0.2-0.4) thickens without obvious distortion - you just get more body. On drums, hard clip with moderate drive crushes transients into a fatter punch. On pads, fold mode adds harmonic complexity that lets a simple sine sound rich and bell-like. Bitcrush on a clean melody instantly turns it 8-bit retro.

Patch a CV into the drive input with an envelope to swell distortion on each note - like a tube amp digging in harder when you play louder. An LFO on drive creates rhythmic distortion movement. Modulating the mode parameter discretely (with a gate sequencer) jumps between distortion characters mid-phrase.

Inputs

IN (audio) — Audio input. The signal level going in affects how hard the distortion clips. Hotter signals distort more even at low drive settings.
Drive CV (cv) — Voltage control over the drive amount. Scaled by the Drive attenuverter. Use an envelope to increase distortion during note attacks.
Tone CV (cv) — Voltage control over the tone filter. Sweep the brightness of the distorted signal with an LFO or envelope.
Mix CV (cv) — Voltage control over the dry/wet mix. Automate the blend for parts that alternate between clean and distorted.

Outputs

OUT (audio) — Distorted audio output with the dry/wet mix applied.

Controls

Mode — Distortion algorithm (0-4). 0 = Soft clip (warm tube). 1 = Hard clip (aggressive). 2 = Fold (metallic wavefolding). 3 = Rect (octave-up fuzz). 4 = Crush (bitcrusher).
Drive — Distortion intensity (0 to 1). Higher values push the signal harder into the clipping algorithm. In Crush mode, this controls how much bit depth is reduced.
Tone — Post-distortion tone shaping (-1 to +1). Center is neutral. Turn left for a darker sound (lowpass). Turn right for a brighter, more aggressive sound (highpass).
Mix — Dry/wet blend (0 = fully dry, 1 = fully distorted). Use low values for subtle saturation or parallel distortion effects.
Drive Atten — Attenuverter for the Drive CV input (-1 to +1). Scales and optionally inverts the incoming CV before it modulates the drive amount.

Inspired by

Distortion in modular synthesis spans two traditions. East-coast: soft tube saturation, transistor fuzz, full-wave rectification (the Tonus Octave). West-coast: Don Buchla's wavefolders, where overdriving a sine into a folding circuit generates harmonic-rich, additive-style timbres. Bitcrushing is the digital-era addition - sample-rate and word-length reduction for lo-fi grit. We bundle all five characters into one module with shared CV-controlled drive and a post-distortion tone filter.

Buchla 259 wavefolder
Krohn-Hite tube saturators
classic fuzz pedals
lo-fi bitcrushers

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