Sources
VCO
Voltage-controlled oscillator — the basic sound source. It produces a continuous, pitched tone.
Learn about it in Oscillators: where every sound starts
How it works
Pick a waveform: SIN is pure and soft, TRI is a little brighter, SAW is buzzy and rich (great into a filter), SQR is hollow and woody. Pitch is set by Tune + Oct + Fine, then pushed around by whatever is patched into V/OCT and FM. The oscillator never stops — use a VCA + envelope to make notes start and end.
Inputs
| V/OCT | Pitch control, 1.0 = one octave up (−1.0 = one down). Patch a Keyboard, Sequencer or Quantizer here to play notes. A small LFO here gives vibrato. |
|---|---|
| FM | Frequency modulation, linear. The signal is multiplied by FM Amt and added to the frequency in Hz. Patch another VCO here (at audio rate) for metallic, bell-like FM tones. |
Outputs
| OUT | The main waveform, roughly −1 to +1. |
|---|---|
| SUB | A square wave one octave below, for extra weight under the main tone. |
Knobs and switches
| Tune | Base frequency. Defaults to C4 (261.6 Hz) so keyboards play in tune. |
|---|---|
| Oct | Shifts by whole octaves. |
| Fine | Detune in cents (1/100 of a semitone). Slightly detune two VCOs for a fat chorus. |
| FM Amt | How strongly the FM input bends the frequency, in Hz per unit of input. |
Patches to try
- Two VCOs, one detuned +7¢, both into a Mixer → instant fat lead.
- VCO B → VCO A’s FM input with FM Amt around 200 Hz for bells.
Lessons that use the VCO
Each one opens as a working patch in the synth.
- 01 · Your First Note
- 02 · Envelopes
- 03 · Subtractive Synthesis
- 04 · Movement with LFOs
- 05 · Mixer: Fat Sounds
- 06 · Scope: Seeing Sound
- 07 · Clock & Sequencer
- 10 · Space: Delay & Reverb
- 12 · FM: Audio-Rate Modulation
- 13 · Drive & Wavefolding
- 14 · Bitcrusher: Lo-Fi
- 15 · Vowel: Make It Talk
- 16 · Chorus, Phaser, Flanger
- 19 · Low-Pass Gate: Plucky Notes
- 21 · Generative Melodies
- 23 · Slew: Glide Anything
- 24 · Scale/Offset: Signal Surgery
- 25 · Chords & Arpeggios
- 26 · Polyphony: Play Chords
- 27 · Stereo & Sidechain
- 29 · Switch: A New Melody Every Bar
- 31 · Turing Machine
- 37 · XY Pad: Play by Touch
- 38 · Lorenz: Chaos
- 41 · Gamepad & Phone Tilt
- 42 · Mic & Envelope Follower
- 43 · Vocoder
- 47 · Spectrum & Tuner
Words to know
- Oscillator — A sound source that repeats a wave shape over and over, making a pitched tone.
- Waveform — The shape of one cycle of a wave, which decides how bright or hollow a tone sounds.
- V/OCT — The pitch standard: each +1 on the input raises the pitch by one octave.
- FM — Changing an oscillator’s frequency with another signal, often at audio rate, for bells and metallic tones.