Symmetry and asymmetry as a physical and perceptual feature of the complementary pair of beating sinusoids

摘要

Beating sinusoids are an interesting case of a simultaneous change of intensity and fre- quency achieved without the need of a modulator. Studies of the perception of beats provide numerous data concerning also the sound pitch perception. Hitherto, the following conclu- sions have been made from those studies: I) if the amplitude of one tone is much larger than the amplitude of the other one, of the two-tone complex, the pitch shifts towards the frequency of the larger amplitude tone; ii) if the amplitudes of the two tones are the same, the pitch is localized precisely at the arithmetic average of the two tone frequencies.