lfo

lfo · modulation · schema v1

Clockable LFO with four phase outputs (0deg / 90deg / 180deg / 270deg).

A low-frequency modulation source: one oscillator emits the same wave at four phase taps (0°/90°/180°/270°) so a single LFO can sweep several voices in stereo or quadrature without re-tuning. Rate sets the cycle speed, Shape continuously morphs the waveform (sine → saw → square), and Depth scales the swing. In a shared/multiplayer rack the phase is anchored to the rack's shared clock so every client sees the same value at the same moment; solo on the public canvas it simply free-runs from phase 0.

the faceplate

#	control	what it does
1	Rate	How fast the LFO cycles, from 0.01 Hz (one sweep per ~100 s) to 100 Hz (audio-rate for FM-style use), on a log fader. Sets the speed shared by all four phase outputs; the clock input overrides phase, not rate.
2	Shape	Continuously morphs the waveform across the 0–2 range: 0 = sine, 1 = saw, 2 = square, with smooth crossfades in between (e.g. value 0.5 = halfway sine↔saw). The fader's glyphs mark sine / saw / square.
3	Depth	Output amplitude / swing, applied as gain = depth × 2 and not clamped: 0 = still (flat at the 0 center, no modulation), 0.5 = unity ±1 (the default, matches legacy patches), 1 = ±2 (deliberately beyond the normal ±1 range). Orthogonal to shape — it only scales the swing, never shifts the center.

inputs

id	cable	what it does
`clock`	gate	External clock — each rising edge (crossing above 0.5) hard-resets the oscillator to phase 0, locking the LFO to an incoming pulse train (e.g. a shared sequencer's tempo). The reset is intentionally hard with no smoothing, so a click on the edge is expected; Rate still sets the speed between pulses — the clock only re-zeros the phase, it does not measure the period or change the rate. gate / trigger
`rate`	cv	CV that scales the Rate knob on a logarithmic axis — ±1 multiplies the rate by about 100× / one-hundredth (≈ ±6.6 octaves of speed). Sample-and-held once at the start of each audio block so multiple clients stay phase-aligned despite sub-block CV latency differences. control voltage (CV); modulates rate (multiplicative ≈ octaves — ±1 CV spans the param’s log range)
`shape`	cv	CV that displaces the Shape control, sliding the waveform morph (sine → saw → square) up or down. Read per-sample (a-rate) so the morph stays smooth. control voltage (CV); modulates shape (additive offset — ±1 CV sweeps the full range, centered on the knob)
`depth_cv`	cv	CV that sums into the Depth control, modulating the output swing amount the same way the Rate/Shape CV inputs offset their params (labeled DEPTH on the panel). control voltage (CV); modulates depth (additive offset — ±1 CV sweeps the full range, centered on the knob)

outputs

id	cable	what it does
`phase0`	cv	The LFO at 0° (the reference phase). Bipolar wave centered on 0; its swing magnitude is set by Depth (0 = flat/still, 0.5 = unity ±1, 1 = ±2). control voltage (CV)
`phase90`	cv	The same LFO advanced a quarter cycle (phase + 0.25) — the 90° tap, useful as the offset partner for quadrature/stereo modulation. control voltage (CV)
`phase180`	cv	The same LFO advanced half a cycle (phase + 0.5) — the 180° tap; for the sine shape this is a polarity inversion (moves opposite phase0), useful for ping-pong / push-pull modulation. control voltage (CV)
`phase270`	cv	The same LFO advanced three-quarters of a cycle (phase + 0.75) — the 270° tap, completing the 0/90/180/270 quadrature set off one shared oscillator. control voltage (CV)

params

id	label	range	default	curve
`rate`	Rate	0.01..100Hz	1	log
`shape`	Shape	0..2	0	linear
`depth`	Depth	0..1	0.5	linear

source

lfo.ts on GitHub.