Control LFO

• Control
• Since 0.2.0
• lfo
• modulation
• control
• tempo

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Control LFO is a low-frequency oscillator whose output is a control lane, a number between 0 and 1 that moves in a repeating cycle. It runs on its own, and an optional reset input restarts it.

What it does#

Shape picks the waveform: sine, triangle, saw, square, or one of two random shapes. Rate sets cycles per second from 0.01 to 40 Hz on a logarithmic control. Setting Beats above 0 locks the cycle to the shared transport instead, so one cycle lasts that many beats (up to 64) and Rate is ignored; at 0 the oscillator is free-running. Depth is the peak-to-peak size of the swing and Offset is its centre, so the defaults (Depth 1, Offset 0.5) sweep the whole 0 to 1 range. Phase sets where in the cycle the oscillator starts. The output is a single control lane.

Reset#

A rising edge (0.5 or more) on the reset input restarts the cycle at the Phase parameter, free-running or locked to Beats, and does not report a cycle. Cable a clock or an Envelope done into it to restart a sweep on every note. The random shapes restart their sequence too.

Random shapes#

Random step holds one value per cycle; Random smooth glides from each cycle's value to the next with an eased curve. Values are drawn from a generator seeded by the node's path, so every host, block size and replay agrees, and a transport seek lands on the same values. Depth and Offset scale them like any other shape.

Events#

The cycle outlet sends an event: it is 1 for one block whenever the phase wraps from the end of a cycle back to the start, free-running or locked to Beats, and 0 otherwise. The first block does not count; a transport seek that moves the beat across a cycle boundary does. Cable it into a trigger input, such as Counter, to make a clock that ticks once per cycle whatever the Shape. Because control runs once per audio block, a cycle shorter than a block still reports one pulse per block, never more.

When to use it#

Use it to produce a moving control signal as an explicit node that can be scaled, smoothed, combined or compared downstream. To turn the 0 to 1 swing into a different range, follow it with Scale; to slow its edges use Smooth.

Ports#

Parameters#

Shape (shape)#

Sine, Triangle, Saw, Square, Random step or Random smooth. A discrete choice. Square jumps between two levels, which makes it a handy clock for Counter or Sample and hold.

Rate (rate_hz)#

Cycles per second, 0.01 to 40 Hz, used when Beats is 0.

Beats (beats)#

Beats per cycle, 0 to 64, locked to the shared transport. 0 hands control back to Rate.

Depth (depth)#

The peak-to-peak size of the swing, 0 to 1. At 0 the output is a steady line at Offset.

Offset (offset)#

The centre of the swing, 0 to 1. Depth and Offset together decide how much of the 0 to 1 range is used.

Phase (phase)#

The starting phase of the cycle, 0 to 1, and where a Reset edge restarts it. Two LFOs with the same Rate or Beats and different Phase move in step but offset in time.

Skew (skew)#

Moves the Triangle's peak earlier or later in the cycle, or bends the Saw so its midpoint arrives at that point. 0.5 is the plain shape and leaves the output exactly as it was; the other shapes ignore it.

Tips#

• Keep Depth and Offset consistent: a Depth of 1 with an Offset away from 0.5 pushes part of the swing past the 0 to 1 range.
• Use Beats for anything that should stay in time with the music, and Rate for slow drift.
• A control lane has no sound of its own. It acts when it is connected to a node that takes control input.
• Prefer cycle over a square wave when you need one tick per cycle: it fires on the wrap whatever the Shape, Depth or Offset, and stays a one-block pulse.

See also#

Scale, Smooth, Math, Cables.

Help patches

Each help patch is an ordinary Toy that teaches one idea. The diagram shows the Patch; the preview shows its Frame. Open it in TuneToys to play and edit it.

1. Shape a control wave

beginner Teaches: shape, rate_hz, depth, offset

A control LFO with shape, rate, depth and offset beside a steady tone.

Connections as text

• Oscillator audio output connected to Patch outputs audio input

• Control LFO makes a 0 to 1 control lane. Shape and Rate set the motion.
• Depth is the size of the swing and Offset is its centre.
• The tone is only here so the Toy plays; the lane is available to any control input.

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2. Lock two LFOs to the beat

intermediate Teaches: beats, phase

Two tempo-synced LFOs with a shared cycle length and a phase offset.

Connections as text

• Oscillator audio output connected to Patch outputs audio input

• Beats above 0 syncs the cycle to the shared transport and replaces Rate.
• Both LFOs share a cycle length; Phase on the second one offsets it in time.

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3. Tick once per cycle

intermediate Teaches: rate_hz, shape, control-lanes

An LFO swells the level with its wave while its cycle outlet clocks a counter that picks the next pitch, whatever the shape.

Connections as text

• Oscillator audio output connected to Gain audio input
• Gain audio output connected to Patch outputs audio input
• Control LFO control output connected to Gain @level input
• Control LFO cycle output connected to Counter trigger input
• Counter control output connected to Select lanes control input
• Select lanes control output connected to Scale control input
• Scale control output connected to Oscillator @frequency input

• The control lane (0 to 1) rides the gain level, so you hear the Shape.
• cycle is 1 for one block when the phase wraps: a clock that ticks once per cycle.
• The counter wraps at 4, so the pitch walks four steps and starts over.

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4. Reset, skew and random

intermediate Teaches: skew, rate_hz

A slow clock resets a skewed triangle so it always restarts in phase, and a random-smooth LFO wanders the pitch.

Connections as text

• Oscillator audio output connected to Gain audio input
• Gain audio output connected to Patch outputs audio input
• Control LFO “clock” control output connected to Control LFO “wave” reset input
• Control LFO “wave” control output connected to Gain @level input
• Control LFO “drift” control output connected to Oscillator @frequency input

• Reset restarts the phase on a rising edge.
• Shapes 4 and 5 are seeded from the node path, so they replay exactly.

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Related nodes

• Scale Map a control range onto another with a curve, clamp and inversion. Depth and offset for any modulation.
• Smooth Slow a control lane down with separate rise and fall times so jumpy sensors and buttons stop clicking.
• Math Arithmetic on any signal, lane by lane: add, multiply, divide, power and more on audio or control operands. The output runs at the rate of its fastest input.