Decay

Decay picks up where attack leaves off. Once the sound reaches its peak, the decay stage determines how fast it drops to the sustain level that is held for the rest of the note. On sounds with no sustain — like a plucked string or a struck bell — decay effectively controls the entire tail length, since the sound falls from its peak toward silence. A short decay produces snappy, percussive results, while a long decay creates a slow, gradual settling. Decay is especially powerful on filter envelopes, where it shapes how quickly the initial brightness collapses, giving you the classic filtered pluck and the punchy opening of many bass and lead sounds.