Envelope

The shape of a sound's amplitude in time. Graphical representation of the envelope of a sound object may show distinctive features in its attack or onset transients, stationary state, internal dynamics and decay.

Envelope generators are used in electronic music and sound synthesizers.

The envelope of a sounds is its macro-level amplitude behaviour in time, whereas its micro-level pattern of sound pressure variation is its waveform.

Compare diagrams under compression, drone, stationary sound.

For spectral envelope see frequency response and spectrum.

Generalized sound envelope showing distinctive features.

Graphic level pattern of recorded sounds made with a level recorder, showing characteristic envelopes which include environmental reverberation during the decay portion.