Perceived pitch extends continuously down to a few hertz as pulse counting

Evidence

A wooden yardstick pressed firmly on a tabletop with a few centimeters protruding off the edge vibrates at say 60 Hz and so has a pitch of 60 Hz when “plucked.” Let more of the stick protrude, and the vibration frequency slows to 10 Hz. The large number of harmonics of 10 Hz make the repetitious tapping sound quite audible in spite of the 0.1 s period. We can almost count the number of periods per second; at 5 Hz, we can count them. The 60 Hz frequency has become 10 Hz or 5 Hz. The sound is still audible as we slide from 60 to 5 Hz. At what point does it stop having a pitch? … The point is, it doesn’t stop having a pitch. The pitch is 5 Hz. Once digested, this simple example shows that the residue pitch effect is a necessity, not an illusion. Our hearing must grade from tone into counting continuously with no abrupt changes. The residue pitch becomes the counting frequency, which is also necessarily the “pitch.” — Eric J. Heller, Why You Hear What You Hear- An…, 2185

Categorization

• DEFINE: This reframes what pitch means — the residue pitch equals the counting frequency, unifying tone and rhythm perception.
• CANDY: A great kitchen-demo fact: a plucked yardstick’s pitch is literally its vibration frequency, countable down to 5 Hz.