An investigation of different timbral attributes as markers determining metrical structure

Abstract

Timbre attributes such as spectral locus, spectral density, and temporal envelope slope were studied to determine their relative effectiveness as accent markers defining metrical structure. Complex-tone sequences comprising 12 tones were used as stimuli with points of timbre change at positions implying a triple meter, quadruple meter, compound meter (both triple and quadruple), or unaccented sequences with no timbre changes. Tones at accented positions were made to differ from the rest by using different spectral densities (1, 2, 4, or 8 harmonic components), by changing the locus of components, and by changing the slopes of a two-part temporal amplitude envelope. Listeners were asked to report if the sequence had a triple meter, quadruple meter, ambiguous meter, or no meter. Results thus far indicate that each of the timbre markers used is individually capable of bestowing metrical structure on a sequence. However, when competing cues exist to offer alternative interpretations of meter, more dense spectra appear to dominate over less dense, higher centers of gravity over lower, and sharper attack functions over more gradual rise times.