The ears are capable of generating sound. See: https://en.wikipedia.org/wiki/Otoacoustic_emission https://en.wikipedia.org/wiki/Otoacoustic_emission The main

The ears are capable of generating sound. See: https://en.wikipedia.org/wiki/Otoacoustic_emission https://en.wikipedia.org/wiki/Otoacoustic_emission The main function of this system is to protect the ear from loud sounds—noise canceling and/or modulate sensitivity as a function of spectrum.