ADSR

A gated four-stage envelope and amplifier with Analog, Relative, and Digital response models plus a sustain-centered Bias output.

What it does #

ADSR rises during Attack, falls toward Sustain during Decay, remains at Sustain while the gate stays high, and returns to zero during Release after the gate closes. Its signal output can modulate other modules, while the built-in amplifier applies the same contour directly to incoming audio.

Controls and ports #

Gate In starts and holds the envelope; the gate pre-cord can add the device's note gate. Attack, Decay, Sustain, and Release define the four stages. Relative and Digital expose stage-curve controls, Analog uses a fixed circuit-style response, Model selects the engine, and Affect Voice Lifetime can keep a polyphonic voice alive until the contour finishes. Outputs include envelope, amplified audio, wireless modulation, and Bias Out.

Practical uses #

• Use the amplifier path as the main amplitude contour for a conventional played Grid synthesizer.
• Use the envelope signal separately for filter, pitch, or timbre movement while another envelope controls volume.
• Use Bias Out for modulation centered around zero at the Sustain level, so the sustained note applies no offset.

Things to know #

• Decay runs while the gate is still high; Release begins only when the gate becomes low.
• With the gate pre-cord enabled, the patched Gate In is combined with the device note gate. Disable the pre-cord when the cable should have exclusive control.
• Analog, Relative, and Digital are different envelope engines, not merely three curve presets; their timing and VCA response can differ at the same visible settings.
• Bias Out subtracts the current Sustain value from the envelope, making the signal zero at the sustain plateau.
• Affect Voice Lifetime is relevant in polyphonic Grid patches and can keep processing active until the envelope falls below its internal end threshold.

Technical details #

A high-confidence Nitro implementation candidate supports the technical summary, but the visible-module mapping remains inferred.

The confirmed envelope/grid_adsr wrapper assigns Model 0 to Relative, 1 to Analog, and 2 to Digital. It dispatches respectively to adsr.proc, adsr.grandmother, or adsr.digital, linearly upsamples the returned state to the Grid output, uses a separate grandmotherVCA transfer in Analog mode, and calculates Bias Out = envelope - sustain. The gate threshold is 0.5; with the pre-cord active it tests the maximum of device gate and patched gate. A companion Relative ADSR body advances each stage by a time-normalized increment multiplied by M(c,x) = ((1+0.8c)-1.6c*x)^2 * (1+2.4|c|), which bends the rate across the current stage. The imported Analog and Digital inner equations remain unavailable.

Nitro port	Type
gateIn	InputAudioPortType
useDeviceGateIn	InputValuePortType
deviceGateIn	InputAudioPortType
attack	InputAudioPortType
decay	InputAudioPortType
sustain	InputAudioPortType
release	InputAudioPortType
attackCurve	InputAudioPortType
decayCurve	InputAudioPortType
releaseCurve	InputAudioPortType
affectVoiceLifetime	InputValuePortType
character	InputValuePortType
out	OutputAudioPortType
outGateScalar	OutputAudioPortType
outScalar	OutputAudioPortType
outVCA	OutputAudioPortType
outBiased	OutputAudioPortType

Open questions #

• Measure stage duration and curve shape for all three Models, including retriggering from every stage and parameter changes while running.
• Measure the Analog VCA transfer separately from its envelope signal and verify Bias Out during moving Sustain automation.
• Confirm gate pre-cord combination, four-sample gate downsampling, voice-lifetime threshold, stereo lanes, and zero-time settings.

Version and sources #

Checked against Bitwig Studio 6.0.6. This page combines Bitwig's module metadata, the existing Grid course and guides, and Nitro analysis where the mapping is strong enough to support a technical statement.

Related material #

• Grid Modules course reference

Return to Bitwig Grid Modules or the Grid Modules course lesson.