ADSR envelopes: setting attack, decay, sustain and release with intent
Four sliders, three times and one level: the ADSR envelope shapes the life of every note. How it works, and starting settings for the most common sounds.
An oscillator produces a continuous tone. What turns that tone into a note, with a beginning, a body and an end, is the envelope. The most common one is named after its four controls: ADSR, for Attack, Decay, Sustain and Release.
Three times and one level
Here is what trips most people up: the four sliders do not measure the same thing.
- Attack: how long the envelope takes to rise from zero to its peak once a key is pressed.
- Decay: how long it takes to fall from the peak to the sustain level.
- Sustain: a level, not a time. The envelope sits there for as long as the key is held.
- Release: how long it takes to return to zero once the key is let go.
It follows that with sustain at maximum, decay has no audible effect, because there is nothing to fall to. With sustain at zero, the note dies away by itself at the end of the decay, even while you keep the key down.
One envelope for volume, another for the filter
Most subtractive synths use one envelope for the amplifier (the loudness of each note) and another to modulate the filter or pitch. Korg’s minilogue xd is a good example: its amp envelope has full ADSR controls, while the second envelope offers attack and decay only, with an intensity control and three destinations (pitch, oscillator 2 pitch or filter cutoff). The minilogue xd specifications list every parameter.
Pair a short filter envelope with a longer amp envelope and you get the classic pluck: a bright attack that darkens straight away.
Starting points
| Target sound | Attack | Decay | Sustain | Release |
|---|---|---|---|---|
| Pad | slow | medium | high | long |
| Bass | instant | short to medium | medium to high | short |
| Pluck, percussion | instant | short | zero | short |
| Organ | instant | no effect | full | very short |
Treat these as starting points rather than recipes: a “slow” attack on one instrument is not the same length on another, since curves and ranges vary from maker to maker.
Envelopes and voice count
On a polysynth, each voice has its own envelopes, so each note in a chord lives its own life. On a paraphonic synth, notes often share one envelope, which changes how chords behave; our guide to polyphony and paraphony goes into the details. The principle is the same on a Eurorack system, where the envelope becomes a module you can patch anywhere, and on a software synth.
Korg’s own introduction to the minilogue xd shows its envelopes in action:
My take
Envelopes are the most underrated part of a patch. Hours go into oscillators and filters, yet a badly placed decay is enough to make a sound stiff or limp. Try this: take a preset you like, zero both envelopes and rebuild them by ear. Ten minutes of that teaches more about the sound than any spec sheet.