Can humans perceive the fundamental pitch of a harmonic series if the fundamental frequency is missing?

• A. Yes
• B. No
• C. Only with training
• D. Only at high frequencies

Answer: (A)

When a harmonic series is present but the fundamental frequency is missing, you still hear the pitch of the fundamental because the auditory system groups the remaining harmonics by their regular spacing. The harmonics lie at integer multiples of the fundamental, so the distance between adjacent frequencies equals the missing fundamental frequency. The ear and brain extract that periodic rhythm from the waveform—through temporal coding in the auditory nerve and pattern recognition in the auditory pathways—and interpret it as the presence of the fundamental pitch even though no energy sits at that frequency. This phenomenon, often called the missing fundamental, shows that pitch can be determined by the spacing of harmonics, not only by the actual spectral peak at the fundamental. For example, harmonics at 400 Hz, 600 Hz, and 800 Hz imply a fundamental of 200 Hz, which is perceived even though 200 Hz is not present as a component.