In Search of the Missing Fundamental: by Richard K. Jones
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Pitch Perception Duplicity

If the sound spectra of timpani contains only a handful of partials which are near-harmonic at best, how does the human auditory system interpret this information so that we perceive its sound as having a pitch with harmonicity, especially if the spectrum does not include the fundamental?

Human pitch perception is a complicated sensory phenomenon involving numerous sciences such as physics, psychology, psycho-physics, physiology, and neurological science. Beginning with the spirited debate between physicists August Seebeck and Georg Ohm in the middle of the 19th century, the scientific community has been somewhat divided in their views regarding how humans (mammals in general) perceive pitch. Attempts have been made to create a unified theory of how we perceive pitch by searching for that single parameter of sound and the mechanism that can account for the both the pitch of single sine tones and that of complex waveforms. To this day, that search has yielded volumes of information and numerous theories, but no one unified theory has been proven that can explain how humans perceive pitch.

Over the years, pairs of competing theories (and variations thereof) have prevailed in attempting to explain what human pitch is, what the process the human ear uses in coding the information it collects and what part(s) of the auditory cortex the brain uses for processing the information. No one theory can completely explain these processes and there is much speculation that perhaps at least two processes functioning simultaneously.

Is our concept of pitch based on a fixed spectrum similar to a Fourier series or is it completely subjective? How is the pitch coded once it reaches the inner ear? Once it has reached the auditory cortex of the brain, which parts of the brain are used for interpreting this information? It would seem that with two working theories for each step in the process, maybe nature has given us the benefit of the doubt.

The saga begins with a debate about the pitch of a complex tone between two scientists, August Seebeck (1805-1849) and Georg Simon Ohm (1789-1854).

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