Saturday Night Randomry

Some background:

In the late 1940s John Cage visited the anechoic chamber at Harvard University. An anechoic chamber is a room designed in such a way that the walls, ceiling and floor will absorb all sounds made in the room, rather than bouncing them back as echoes. They are also generally extremely soundproof. Anechoic chambers are widely used for measuring the acoustic properties of instruments and microphones, and for performing psychoacoustic experiments.

Cage entered the chamber expecting to hear silence, but as he wrote later, he "heard two sounds, one high and one low. When I described them to the engineer in charge, he informed me that the high one was my nervous system in operation, the low one my blood in circulation."

I don't know if this explanation is accurate, but this experience is often described as the inspiration behind the famous Cage composition 4' 33".