Envelopes

Source of truth: the doc comments on each module struct in patches-modules/src/ define the canonical port names, parameter ranges, and behaviour. This page is kept in sync with those comments.

Adsr — Multi-channel DADSR envelope with built-in VCA

Multi-channel Attack-Decay-Sustain-Release envelope generator with an optional pre-attack Delay phase and built-in VCA pass-through. One module emits N independent envelopes (one per channel) driven by a single shared trigger and gate.

With channels = 1 (the default) it behaves as a conventional single-channel ADSR — env.out, env.vca_in, env.vca_out address channel 0 implicitly. Use Adsr([amp, filt, vib]) or Adsr(3) to get multiple envelopes per trigger/gate.

Each channel has its own delay/attack/decay/sustain/release/shape, and an optional VCA stage: if vca_in[c] is connected, vca_out[c] emits vca_in[c] * env[c]. Useful for tying amplitude, filter, and modulation envelopes to the same note event without wiring N separate modules. A rising trigger enters the per-channel Delay phase (output held at 0 for delay[c] seconds) before Attack begins. Releasing the gate during Delay returns the channel to Idle without emitting any envelope.

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Parameters

Env — Multi-stage breakpoint envelope with key-follow

Where Adsr has a fixed attack/decay/sustain/release shape, Env runs an arbitrary number of (time, level, curve) stages with a designated sustain stage — enough to express D50-style contours ADSR cannot (attack spike → dip → secondary swell → sustain). The stage count is the module’s channels axis: Env(5) is a five-stage envelope. One module is one envelope (mono); use multiple instances for multiple envelopes.

Stages 0..sustain_stage form the pre-sustain contour; the envelope holds at level[sustain_stage] while the gate is high, then runs the remaining stages sustain_stage+1..N as the release tail on gate-off. Designate a final stage with level = 0 for a release to silence. A re-trigger restarts from the current level (no click), and a gate-off during the pre-sustain contour jumps straight into the release tail.

Key-follow shortens stage times with pitch, as real resonators decay faster up the keyboard: time_scale = 2^(-keyfollow * (voct - ref_key)), so keyfollow = 1.0 halves all stage times one octave above ref_key. It is applied per tick, so a bending voct re-scales the contour live.

Velocity scales stage levels: the effective velocity (1.0 if the input is unconnected) is mapped to a level multiplier 1 - vel_depth * (1 - velocity) and latched at the trigger, so an in-flight envelope keeps a stable scaling.

Route out to an oscillator voct / phase_mod or a filter cutoff for the D50 attack pitch-blip or filter sweep — that’s a patch idiom, not a port.

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Parameters

PolyAdsr — Per-voice DADSR

Same envelope shape as Adsr (delay/attack/decay/sustain/release/shape) but each voice has independent state, driven by per-voice trigger / gate poly cables. Optional per-voice VCA via vca_in.

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Parameters — same names and ranges as Adsr. Parameters apply identically to all voices.

PolyEnv — Per-voice multi-stage envelope

The 16-voice form of Env: same multi-stage contour, key-follow, and velocity scaling, but each voice holds independent state driven by per-voice trigger / gate / voct / velocity poly cables. All voices share one stage configuration. The stage count is the channels axis (PolyEnv(5) = five stages); sustain_stage and the release-tail semantics are identical to Env.

Key-follow and velocity are computed per voice: time_scale = 2^(-keyfollow * (voct[v] - ref_key)) and the level multiplier 1 - vel_depth * (1 - velocity[v]), latched at each voice’s trigger. Unconnected voct reads as 0 and unconnected velocity as 1.0.

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Parameters — same names, ranges, and defaults as Env (time[i], level[i], curve[i], sustain_stage, keyfollow, ref_key, vel_depth). Parameters apply identically to all voices.