A sine generator is used in conjunction with a powered loudspeaker to generate tones at frequencies that challenge the limits of human hearing.

A0, speaker on cart near workbench or J1

Connect function generator to speaker (preferably with an integrated amplifier). Set tone frequency between 20 and 20000 Hz (the sonic range). Below 20 Hz, too low a frequency; above 20kHz, too high to be heard. The older the effective age of the ear, the lower the higher limit is (students might be in the 16 to 20 kHz range, staff and faculty in the 13-16kHz range or lower). Annoy people: set frequency to 30-40 kHz. After a few minutes people will start to feel uneasy even though they cannot hear anything.

PIRA DCS 3C20.10