911 eg

moog911 · modulation · schema v1

911 Envelope Generator (moogafakkin System 55/35 clone — categorized under Ports -> moogafakkin). NOT a literal ADSR: a three-time-constant CONTOUR generator with a single sustain LEVEL. On S-trigger (gate high) it ATTACKS over T1 from 0 to the peak (1.0), INITIAL-DECAYS over T2 down to ESUS (the sustain level), then HOLDS at ESUS while the gate is held; on release (gate low) it FINAL-DECAYS over T3 back to 0. Trigger-close forces the T3 final-decay stage regardless of which stage was running, so a short trigger that releases mid-attack still decays over T3 from wherever it reached. T1 / T2 / T3 each span up to 10 s (log knobs); ESUS is a linear 0..1 level. Outputs the unipolar 0..1 contour on env plus an inverted tap (1 - env) on env_inv for ducking / sidechain modulation. CV inputs (t1_cv / t2_cv / t3_cv log-scaled, esus_cv linear) sweep each control. DSP is own-code: a clean-room exponential-segment contour generator (not a port of any moogafakkin schematic or copyleft source - permissive only). Beige moogafakkin faceplate (the intrinsic always-on look shared by the moogafakkin module family).

A clean-room recreation of the Moog 911 Envelope Generator — the classic Moog 'contour generator', NOT a literal ADSR. It's a unipolar (0..1) envelope shaped by three time constants and one sustain LEVEL: when the TRIG gate goes high it rises to full over the ATTACK time (T1), then falls to the SUSTAIN level over the INITIAL-DECAY time (T2) and holds there for as long as the gate stays high; when the gate falls it returns to zero over the FINAL-DECAY time (T3). So the contour is attack → initial-decay-to-sustain → (hold) → final-decay, rather than A-D-S-R. Patch the OUT envelope into a VCA or filter cutoff to shape a note, and use the inverted OUT to duck or sidechain. Mental model: a transient-shaping contour fired by a gate, with separate up/settle/release slopes and a held middle.

the faceplate

5 inputs · 2 outputs · 4 params

about this module

Hover a control, or open the patch panel and hover a jack.

inputs

id	cable	what it does
`gate`	gate	The trigger/sustain gate (an S-trigger). A rising edge starts the contour (ATTACK → INITIAL DECAY → hold at SUSTAIN); the envelope holds at the sustain level while the gate stays high, and the falling edge starts the FINAL DECAY (T3) back to zero. A short gate that falls before settling still triggers a clean release. gate / trigger
`t1_cv`	cv	CV that scales the ATTACK time (T1) around the knob setting: a positive voltage lengthens the rise, a negative one shortens it (log-scaled, so the full natural decade range sweeps centered on where you set the knob). control voltage (CV); modulates t1 (multiplicative ≈ octaves — ±1 CV spans the param’s log range)
`t2_cv`	cv	CV that scales the INITIAL-DECAY time (T2) — how fast the envelope falls from its peak down to the sustain level — around the knob setting (log-scaled). control voltage (CV); modulates t2 (multiplicative ≈ octaves — ±1 CV spans the param’s log range)
`esus_cv`	cv	CV that displaces the SUSTAIN LEVEL (Esus, 0..1) up or down from the knob position, changing the level the contour holds at while the gate is held (linear, unipolar). control voltage (CV); modulates esus (additive offset — ±1 CV sweeps the full range, centered on the knob)
`t3_cv`	cv	CV that scales the FINAL-DECAY time (T3) — the release slope back to zero after the gate falls — around the knob setting (log-scaled). control voltage (CV); modulates t3 (multiplicative ≈ octaves — ±1 CV spans the param’s log range)

outputs

id	cable	what it does
`env`	cv	The contour itself, a unipolar 0..1 control voltage. Patch it into a VCA's gain or a filter's cutoff to shape each note's loudness/brightness over time. control voltage (CV)
`env_inv`	cv	The inverted contour (1 − env): high when the envelope is low and vice-versa. The standard Eurorack ducking/sidechain tap — patch it into a VCA to pull a level DOWN whenever the envelope fires. control voltage (CV)

params

id	label	range	default	curve
`t1`	T1	0.0001..10s	0.01	log
`t2`	T2	0.0001..10s	0.2	log
`esus`	Esus	0..1	0.6	linear
`t3`	T3	0.0001..10s	0.4	log

controls

control	what it does
Esus	SUSTAIN LEVEL (Esus): the level the envelope holds at while the gate is held, from 0 (decays all the way to silence, an AD-style pluck) to 1 (holds at full, no initial decay).
T1	ATTACK time (T1): how long the envelope takes to rise to full when the gate opens — from an instant click to a slow ~10 s swell (log taper).
T2	INITIAL-DECAY time (T2): how long the envelope takes to fall from its peak down to the SUSTAIN level after the attack completes (log taper). This is the 'decay' stage of the contour.
T3	FINAL-DECAY time (T3): the release — how long the envelope takes to fall back to zero after the gate falls (log taper). A trigger close forces T3 from whatever stage the contour was in.

source

moog911.ts on GitHub.