Pitch of Complex Tones

The question of whether the pitch of complex tones is based either on the frequency of the fundamental or on the periodicity of the sound as a whole was studied. Fifteen naïve subjects compared the stimuli A = ∑ n=112 an cos(2πnft) and B = ∑ n=1m an cos[2πn(0.9f)t]+ ∑ n=m+112 an cos[2πn(1.1f)t] and had to decide which of the two stimuli, presented successively during 200-msec intervals, was higher in pitch. The results showed that for m = 1 (fundamental of B was 10% lower in frequency than that of A, and all other harmonics were 10% higher in frequency than A) the pitch changed according to the harmonics for f < 1400 Hz and according to the fundamental for f> 1400 Hz. For m = 2, 3, and 4, the corresponding transition frequency was about 700, 350, and <125 Hz, respectively. This holds for both an = 1 and an = 1/n. The experiments support the view that the pitch of complex tones is based on periodicity rather than on frequency. The description of the experiments is preceded by a historical review.