Music spans nine time scales from infinite to infinitesimal

Curtis Roads distinguishes nine nested time scales of music: Infinite (all sounds), Supra (beyond a single composition), Macro (the whole piece), Meso (sections and phrases), Sound Object (individual notes/events), Micro (grains and transients, 1 microsecond to ~100ms), Sample (the individual digital sample), Subsample (interpolation phenomena), and Infinitesimal (the mathematical point). The micro scale is the primary subject of granular synthesis. The framework clarifies how compositional operations at one level generate perceptual effects at others: grain density changes on the micro scale produce texture changes at the meso scale. Understanding these boundaries prevents category errors when applying time-domain processing.

Examples

A 40ms grain lives on the micro scale. A cloud of grains over 3 seconds lives on the sound-object/meso boundary. An FFT window of 23ms operates on the micro scale.

Assessment

Place these events at the correct time scale: single sample (44100 Hz), 50ms grain, 4-bar phrase, entire album. Then explain which time scale granular synthesis primarily operates on and why.