Mathematics itself is music. See [Mathematics, the Music of Reason][1].
The point I am making here is that to "define (aspects of) music" is *not* a mathematician's goal. That is perhaps the task of someone who is more interested in music and has no interest in mathematics, or perhaps a *lost* mathematician who needs to find credibility by resorting to popular culture, in order to *show* others that mathematics is useful and can *even* define aspects of music.   

  [1]: http://www.amazon.com/Mathematics-Music-Reason-Jean-Dieudonne/dp/3642080987/ref=sr_1_1?ie=UTF8&qid=1341535160&sr=8-1&keywords=Mathematics+the+music+of+reason