Audible Young'S Experiment - Group Listening
To demonstrate interference of sound with two coherent sound sources.
Loudspeakers on rotating boom permanently mounted on oscillator-amplifier.
The oscillator-amplifier is set to approximately 3000 Hz, with identical signals being applied to both loudspeakers. Rotating the loudspeakers past the listeners allows them to observe the interference pattern by hearing the alternating maxima and minima in the intensity pattern.
Ralph Baierlein and Vacek Miglus, Illustrating double-slit interference: Yet another way, AJP 59, 857 (1991).