LFOs: a periodic hand on the knob
Vibrato, tremolo, and wah are one mechanism — a slow oscillator turning a parameter, over and over.
An LFO — low-frequency oscillator — is the same object as lesson 1's oscillator, run so slowly you stop hearing it as a tone (mostly below ~20 Hz) and start hearing it as motion. It never reaches the speakers itself. Instead it is wired to a parameter, and its waveform becomes a hand turning that knob in a perfect loop, forever, at a speed and strength you choose.
The destination is the effect
- LFO → pitch, gentle and ~5–7 Hz: vibrato — the singer's wobble.
- LFO → volume: tremolo — the pulsing of a vintage amp.
- LFO → filter cutoff: wah and slow talking sweeps — brightness breathing on a loop.
The LFO's waveform decides the style of motion: a sine glides, a triangle sweeps evenly up and down, a square snaps between two values like a trill. Rate sets how fast the hand turns, depth how far. Depth is the difference between seasoning and seasickness — most musical modulation is far subtler than a first-timer expects.
One steady tone, one LFO, three destinations. Keep rate and depth fixed and only switch the destination — pitch, volume, filter — and hear the same motion become vibrato, tremolo, wah. Then find the depth where each stops being an effect and starts being character.
Each device carries this on its LFO / MOD pages — and more generously than our toy: the DEST menu offers dozens of destinations (nearly any parameter on the track, not just three), SPD/MULT set the rate — free-running or tempo-synced — and bipolar DEP is the depth, flippable upside down just like the filter envelope's: