Control envelope

A control-rate ADSR, AD or AR envelope on a gate lane, 0 to 1, with velocity scaling and a done event.

Control
Since 0.2.0
envelope
adsr
gate
modulation
velocity

Control envelope as the Patch draws it, at default values: inlets on the left, outlets on the right.

Control envelope turns a gate lane into a 0 to 1 control lane that rises, holds and falls like an envelope. It is the control-rate sibling of Envelope: the same stages and curves, but the result is a lane you cable into any parameter instead of a gain applied to audio.

What it does#

While the gate lane is at 0.5 or more it is held. A rising edge starts the attack; in ADSR the level then decays to Sustain and stays there until the gate falls, then Release returns it to zero. AD ignores the falling gate and runs attack then decay on its own; AR rises to full and holds until the gate falls. Curve bends every segment, Loop repeats whole cycles while the gate is held, and Retrigger chooses whether a new edge starts from the current level or from zero. The stage logic is the audio envelope's own, so the two agree.

Velocity scales the peak from the gate lane's value at the rising edge: at 0 the gate value is ignored, at 1 a gate of 0.75 peaks at 0.75. Use the velocity lane of MIDI to control, or a gate multiplied by a level, to get velocity-sensitive envelopes. The gate must still reach 0.5 to open.

Resolution#

Control runs once per audio block, and the output is the level at the block's last frame. Stage times are exact, but the lane steps about 2.7 ms at 128 frames and 48 kHz, so very short attacks look like a step. Cable the output into a parameter's cable input to let that parameter smooth it.

Events#

The done outlet is 1 for one block when a cycle ends: a release finishes, or an AD decay completes. A retrigger during a release is not a completed cycle. Cable it into Counter or another trigger input.

When to use it#

Use it to shape a filter, a level or any parameter per note, or to build a one-shot modulator from a trigger. Prefer Envelope when the envelope shapes audio directly.

Ports#

Port	Direction	Signal	Lanes
`gate`	Input	Control	1
`control`	Output	Control	1
`done`	Output	Control	1

Parameters#

Parameter	Label	Range	Default	Unit	Scale	Notes
`type`	Type	0 to 2	0		linear	Selects the implemented algorithm. Choices are discrete. Choices: 0 ADSR, 1 AD, 2 AR.
`attack_ms`	Attack	0 to 10000	10	ms	linear	Time to rise to full level.
`decay_ms`	Decay	0 to 10000	120	ms	linear	Time to fall to sustain in ADSR, or zero in AD.
`sustain`	Sustain	0 to 1	0.7	%	linear	Held ADSR level. Stored as a fraction; shown ×100 as a percentage.
`release_ms`	Release	0 to 10000	200	ms	linear	Time to return to zero after the gate falls.
`hold_ms`	Loop hold	0 to 10000	100	ms	linear	Duration of the held part in repeating ADSR/AR cycles. Shown when `loop` is 1.
`curve`	Curve	-1 to 1	0		linear	Continuous concave/linear/convex segment curvature.
`loop`	Loop	0 to 1	0		linear	Repeats complete envelope cycles while the gate is held. Choices: 0 Off, 1 While held.
`retrigger`	Retrigger	0 to 1	0		linear	Where a new gate edge starts the attack. Choices: 0 Current level, 1 From zero.
`velocity`	Velocity	0 to 1	0		linear	How much the gate lane value at the rising edge scales the peak. 0 ignores it.

Type (`type`)#

ADSR, AD or AR. A discrete choice.

Attack (`attack_ms`), Decay (`decay_ms`), Sustain (`sustain`), Release (`release_ms`)#

The stage times and the held level. Decay applies to ADSR and AD, Sustain to ADSR, Release to ADSR and AR.

Loop hold (`hold_ms`)#

How long a looping cycle rests at its held level before releasing. Visible when Loop is on.

Curve (`curve`)#

Concave below 0, linear at 0, convex above 0, applied to every segment.

Loop (`loop`) and Retrigger (`retrigger`)#

Loop repeats cycles while the gate is held. Retrigger picks the start of a new attack: the current level, or zero.

Velocity (`velocity`)#

How much the gate value at the rising edge scales the peak, 0 to 1.

Tips#

A square Control LFO is a quick gate for trying an envelope.
Keep Velocity at 0 for a plain gate; at 1 the gate value is the peak.
Release only has something to do while the gate falls from above zero; done waits for it to finish.

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 note

beginner Teaches: attack_ms, decay_ms, sustain, release_ms

A square LFO is the gate; a control envelope turns each pulse into a swell and fade on the tone.

Patch: Oscillator audio output connected to Gain audio input. Gain audio output connected to Patch outputs audio input. Control LFO control output connected to Control envelope gate input. Control envelope control output connected to Gain @level input.

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 Control envelope gate input
Control envelope control output connected to Gain @level input

A gate at 0.5 or more is held; below it the envelope releases.
The output is 0 to 1 and rides the gain level.

Frame preview (static). Controls show their default values.

Open in TuneToys

2. Velocity and done

intermediate Teaches: velocity, decay_ms

An AD envelope scales its peak by the gate value, and its done outlet steps a counter that picks the next pitch.

Patch: Oscillator audio output connected to Gain audio input. Scale control output connected to Oscillator @frequency input. Gain audio output connected to Patch outputs audio input. Control LFO “gate” control output connected to Math a input. Control LFO “level” control output connected to Math b input. Math out output connected to Control envelope gate input. Control envelope control output connected to Gain @level input. Control envelope done output connected to Counter trigger input. Counter control output connected to Select lanes control input. Select lanes control output connected to Scale control input.