Trigger mode lets a drum envelope complete its decay regardless of note-off timing

Standard ADSR envelopes listen for note-off: releasing a key interrupts sustain and starts the release phase. For drum sounds this is undesirable — a kick drum’s decay should be determined by the patch, not by how long the performer holds the MIDI note. Trigger mode (sometimes called ‘freerun’ or ‘one-shot’) ignores the note-off message entirely: the moment a note-on arrives the envelope runs its attack-decay-sustain-release curve to completion on its own schedule. This makes the drum repeatable and velocity-dependant only through attack or initial level parameters, not through hold time.

Examples

Ableton Operator envelope: set Loop mode to ‘Trigger’. A 300 ms decay now always takes 300 ms regardless of MIDI note length, so quantized or humanised gate lengths do not change drum character.

Assessment

Record a kick drum note held for 2 beats vs. tapped quickly in standard ADSR mode and compare waveforms. Then switch to trigger mode and explain what changes and why.