After trekking to Petsmart this evening to get a Furminator, I sat down to try my hand at visualizing music. With a mix of Processing.org + Minim + some minor post in AE, this is a snippet of the result!
What’s going on: Each particle has a random mass. As the music plays, an FFT breaks down the sound. A spike in volume in the low frequencies energizes high-mass particles, and a spike in volume on higher frequencies energizes the low mass particles. If the energy of a particle reaches a predefined threshold, it spawns children (visible at the end). There are some other forces at play as well in order to get just the right result, but this is the gist.