Fig. 1.

Schematic illustration of the relationship between acoustic periodicity and perceived pitch for pure and complex tones. A pure tone (Upper, blue) and a harmonic complex tone (Lower, red) are shown, which both produce the same pitch corresponding to the note A above middle C, as illustrated by the musical notation in Right Inset. Left shows the time waveforms with a repetition rate of 440 Hz. Right shows the tones’ spectral representations, including the fact that the complex tone does not have any energy at the fundamental frequency (F0) of 440 Hz.