Polyphonic overlapping grains form a grain cloud — granular synthesis's characteristic dense texture

A single stream of grains (one grain at a time) is essentially a stuttering sample playback. The distinctive granular cloud texture emerges only when multiple grains overlap simultaneously — hundreds to thousands in a dense cloud. Each additional simultaneous voice adds density, warmth, and complexity. In Max/MSP, poly~ replicates the grain generator subpatch across N voices, each triggered independently with its own parameters. The cloud’s character is controlled by grain density (how many trigger per second), overlap (average number simultaneously sounding), and parameter spread. This is where granular synthesis truly diverges from conventional synthesis: the composite sound is an emergent texture, not a single controlled waveform.

Examples

A grain cloud at 20 grains/second with 100ms duration = 2 grains overlapping on average (light shimmer). At 200 grains/second with 100ms = 20 overlapping grains (dense, lush cloud).

Assessment

Explain why a single-voice grain generator does not produce the characteristic granular sound. What two variables jointly determine the average number of simultaneously overlapping grains in a cloud?