Modulation
LFO
Low-frequency oscillator — a slow, repeating wave used to move other things automatically.
Learn about it in Modulation: making sounds move
How it works
It works like a VCO but much slower (0.02–60 Hz). The display scrolls the real output over the last few seconds, so you can see the shape, depth and speed. You don’t listen to it directly; you patch it into a CV input to make something wobble: pitch (vibrato), filter cutoff (wah/sweep), VCA (tremolo), delay time (chorus).
Inputs
| RATE | Adds to the rate: +1.0 = +4 Hz. Patch another LFO here for wobbles that speed up and slow down. |
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Outputs
| ± | Bipolar: swings from −Depth to +Depth around zero. Use it when you want to move a knob both up and down from where it is set. |
|---|---|
| + | Unipolar: swings from 0 to +Depth. Use it when you only want to push something upward (e.g. open a filter, never close it). |
Knobs and switches
| Rate | Speed of the wobble. |
|---|---|
| Depth | Size of the wobble. The receiving module usually has its own amount knob too. |
Patches to try
- LFO ± → Filter CV for a classic filter sweep (see Filter help).
- LFO + → VCA CV with VCA Bias at 0 → tremolo.
- LFO with depth ~1% → VCO V/OCT → vibrato.
Lessons that use the LFO
Each one opens as a working patch in the synth.
- 04 · Movement with LFOs
- 11 · Noise: Wind & Hats
- 13 · Drive & Wavefolding
- 15 · Vowel: Make It Talk
- 17 · Wavetable & PWM
- 35 · Granular Clouds
Words to know
- LFO — An oscillator too slow to hear, used to move other things automatically.
- Modulation — Using one signal to change another over time.