Figure 10.

(Color online) The five kinds of timbre percepts in orchestral instrument tones are associated with distinct acoustic features, as depicted in the MPS, and as interpreted semantically (legend color labels). The first perceptual dimension (MDS D1) involves power fluctuations in frequency (“spectral modulations”) associated with amplitude changes in the natural harmonic structure (horizontal purple bands). D2 (overlaid in green) involves 6 Hz amplitude changes (“temporal modulations”) in spectral balance characteristic of vibrato (vertical bands). D3 (orange) overlaid on D4 (red) centers similarly on spectral prominence of alternating harmonics (half the spectral modulation in D1). D5 (blue, the top layer) involves particularly 2 Hz changes (vertical bands). The right side y-axis labels give spectral modulations in units of the period of the pitch fundamental (1/311 s).