4′ 33”

Although often described as a silent piece, 4’33″ isn’t silent at all. While the performer makes as little sound as possible, Cage breaks traditional boundaries by shifting attention from the stage to the audience and even beyond the concert hall. You soon become aware of a huge amount of sound, ranging from the mundane to the profound, from the expected to the surprising, from the intimate to the cosmic –shifting in seats, riffling programs to see what in the world is going on, breathing, the air conditioning, a creaking door, passing traffic, an airplane, ringing in your ears, a recaptured memory. This is a deeply personal music, which each witness creates to his/her own reactions to life. Concerts and records standardize our responses, but no two people will ever hear 4’33″ the same way. It’s the ultimate sing-along: the audience (and the world) becomes the performer.

http://www.classicalnotes.net/columns/silence.html