Pitch can be derived from harmonic spacing even without the fundamental present.

Evidence

The spectral representation contains information about the fundamental frequency in two different ways. The first is that the fundamental frequency is represented as the lowest frequency component in the spectrum. We see this in Figure 6–1 as a harmonic at the 261-Hz frequency. It is extremely common for natural sounds to contain a spectral peak that corresponds exactly to the f0. However, the fundamental frequency is also represented by the relationship between the various harmonics. Note that the spectral peaks occur at multiples of the fundamental frequency (e.g., 261, 522, 783, and 1044 Hz), and as a result they all have a common frequency of 261 Hz. More generally, an easy way to determine the f0 of any sound from its spectrum is to calculate the greatest common frequency (GCF) from the harmonics. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1190

Categorization

• DEFINE: Introduces the two spectral routes to f0 and the GCF concept, foundational to later ‘missing fundamental’ material.
• QUESTION: This sets up the classic question of whether the missing fundamental is still perceived — worth verifying how the audiogram relates.