Patching a subtractive voice: VCO, VCF, VCA & envelopes

This module builds the patch that everything else in Eurorack is a variation of: the monophonic subtractive voice. Whether you are sketching acid lines for a live techno set, giving a hardware voice to a TidalCycles-driven rig over CV, or just needing your first case to make a note instead of a drone, VCO → VCF → VCA with two envelopes is the architecture under the Minimoog, the 303, and most soft synths — learning it here means every future patch reads as a variation you already understand.

The arc moves from listening to performing. Start by patching the raw chain and hearing each stage change the sound: the oscillator as a pitch-tracking tone source, the low-pass filter closing harmonics away, the VCA turning an endless drone into a note. “The canonical subtractive voice patch” is your just-in-time recipe for wiring both envelopes — one shaping loudness, one sweeping cutoff — and “A sequencer controls an oscillator with two connections” walks you through handing pitch and gate to the sequencer so the voice plays itself. From there, remove the training wheels: repatch the voice from a blank panel, then rehearse cutoff-and-resonance sweeps until they feel like playing an instrument rather than testing one, leaning on the resonance atom to find the squelch zone before self-oscillation.

The required atoms are exactly what the capstone cannot be faked without: each module’s function, the subtractive signal flow, the two-envelope patch, sequencer routing, and resonance behaviour. The supporting atoms deepen the same territory — LFO modulation, attenuating envelope depth, filter slopes, pitch-envelope punch, PWM, slew — enriching the voice once the core patch is second nature.

Runnable examples

Generated from the context/ instrument corpus by concept (redistributable idioms only). Do not edit — regenerate with gen-module-examples.mjs.

lowpass-sweep

Noise n => LPF f => dac; 0.2 => n.gain;

_{chuck-0003 · MIT}

s("hh*8").lpf(sine.range(200,4000).slow(4))

_{strudel-0015 · CC0}

adsr-envelope

note("c3").s("sawtooth").attack(0.01).decay(0.1).sustain(0.6).release(0.3)

_{strudel-0205 · CC0}

{ Saw.ar(220) * EnvGen.kr(Env.perc(0.001, 0.2), Impulse.kr(2)) * 0.3 }.play

_{supercollider-0013 · CC0}