‘I was learning the fugue when suddenly a vacuum cleaner started up beside the piano. Well, the result was that in the louder passages, this luminously diatonic music in which Mozart deliberately imitates the technique of Sebastian Bach became surrounded with a halo of vibrato, rather the effect that you might get if you sang in the bathtub with both ears full of water and shook your head from side to side all at once. And in the softer passages I couldn’t hear any sound that I was making at all. I could feel, of course - I could sense the tactile relation with the keyboard which is replete with its own kind of acoustical associations - and I could imagine what I was doing, but I couldn’t actually hear it. But the strange thing was that all of it suddenly sounded better than it had without the vacuum cleaner, and those parts which I couldn’t actually hear sounded best of all. Well, for years thereafter, and still today, if I am in a great hurry to acquire an imprint of some new score on my mind, I simulate the effect of the vacuum cleaner by placing some totally contrary noises as close to the instrument as I can. It doesn’t matter what noise, really - TV Westerns, Beatles records; anything loud will suffice - because what I managed to learn through the accidental coming together of Mozart and the vacuum cleaner was that the inner ear of the imagination is very much more powerful a stimulant than is any amount of outward observation.’ - Glenn Gould’s account of his experience when studying one of Mozart’s Fantasias. Liner notes written by Michael Stegemann (translated by Gery Bramall), found in The Glenn Gould Edition SONY SMK 52 626.
I read this originally from a post of Lawrence Li's on his excellent blog Global Noise Online. GNO is perhaps the best resource regarding Chinese/Asian sound art, noise, and experimental music around.