Limit of audibility: Set of rods that ring at different frequencies.

This is a set of 10 solid metal cylinders suspended on strings to resonate from 4084 Hz to 32,768 Hz. A small wooden hammer is used to strike the bars. The audible range for humans is about 20 Hz to 20,000 Hz. With age, the high frequency limit may shrink to 10,000 hz or less. Ref.:Physics For Scientists and Engineers by Giancoli, 2nd ed., p. 383 PERCEPTION.
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