Granulation segments an existing sound into grains and reassembles them in new time order

Granulation (as a transformation technique) segments a sampled source sound into grains and then reassembles those grains in a new time order and microrhythm. Unlike synthesis from scratch, granulation processes existing material. The granulation algorithm extracts grains from the source file at specified points (random, sequential, or statistically evolving) and schedules them at new times. This enables time-stretching (cloning grains), time-shrinking (deleting grains), scrambling (random reordering), and various textural transformations. Granulation is the basis for harmonizers, pitch-time changers, and time-stretching in professional audio software.

Examples

To time-stretch a recording by 2x: segment it into 20ms grains in left-to-right order, clone each grain, reassemble at original positions times 2. Duration doubles, pitch is unchanged.

Assessment

Define granulation as a transformation of an existing sound. Describe how cloning versus deleting grains during reassembly changes the duration of the source, and why the grain envelope is needed to avoid clicks at the reassembly boundaries.