Speakers from every computer I've owned or used regularly, each playing a square-wave at the frequency of their processor's internal clock, scaled between the average resting human heart-rate and A440. The speakers are hung at average ear level and 7" apart (average distance between a human's ears).

An audio recording of the piece
A detail of the speakers from a Toshiba Tecra 8000 laptop, an Apple Power Macintosh G3, and a Mac PowerBook G4 laptop

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