Last night was the first meeting of a math-music seminar I am attending. It's a joint effort between the music and math departments, and is meant to highlight some of the places where the two subjects intersect.

This first talk dealt with music that is produced from some sort of random process. If you haven't heard this stuff, it is basically a random (in the mathematical and not the Friends sense) sequence of notes or chords of random duration. The scores are produced by some sort of method. One guy (John Cage) placed a blank music sheet over a star chart, and used the stars underneath to plot where the notes would be. Then he flipped coins to determine things like volume and duration. He would generate a bunch and keep the ones that sounded pleasing. This was considered to be his gift; while anyone could generate music this way, he picked out the trials that were best suited to the source they came from, and probably according to some musical theories of which I am not familiar.

The speaker had prepared some music of his own. His method was to determine the chord placement, where the rests go, and pitch using a system with random numbers generated from the "random" decimal representation of the square root of two. Any irrational number could have been used, and the way it was designed, one could theoretically reconstruct the number from the sounds (of course that would involve listening for an infinte amount of time), since each irrational number has a unique digit sequence. So when you listened to the end product, you were in some sense listening to a translation of the square root of two into audio form. I would say that listening to an audio representation of the square root of two ranks right up there with any geeky experience I've had.