"apply a resonator to the ear, most of the tones produced in the surrounding air will be considerably damped; but if the proper tone of the resonator is sounded
Marquardt, Ch.; Leuchs, G. Quantum Light from a Whispering-Gallery-Mode Disk Resonator. Physical Review Letters. 2011-03-15, 106 (11): 113901. Bibcode:2011PhRvL