Granular clouds are statistical sound masses at the meso time scale

Granular synthesis produces not just individual grains but statistical clouds of microevents at the meso time scale. Xenakis identified this as a new type of sound mass distinct from traditional orchestral masses: instead of continuous tones in heterophony, a cloud is defined by statistical parameters - density, frequency bandwidth, duration, amplitude envelope - that together shape an emergent texture. The individual grains are insignificant on their own; only the collective statistics of thousands of grains determine the perceived result. Clouds can be sparse (transparent, pointillist) or dense (opaque, continuous), and can evolve over time through controlled parameter variation.

Examples

A cloud might be specified: duration 5s, frequency band 200-800 Hz, grain density 50/sec, grain duration 30ms. The individual grain frequencies are random within the band.

Assessment

What are the key parameters that define a granular cloud? Explain how changing density from 5 to 200 grains/sec changes the perceived character of a cloud.