Another example of the "order" of music comes in the scale of notes employed. The basic 12-note chromatic scale used in the West has its notes separated by twelfth-root of two (binary logarithmic) intervals. Even more to the point, the diatonic scales (the seven note groupings within the chromatic scale) which define the various keys, are based on an approximation to the "overtone series
" sequences, in which note frequencies are related as integral multiples of each other. This symmetry seems to, we might say, strike a chord with people.
All the symmetries, the patterns of order within music, the note relationships, the rhythms, the repetitions, etc. seem to be very pleasing to us. During the Twentieth Century, many within the "academe" decided that it was time to broaden the definition of what music is, and loosen the reins of symmetry. (Probably a way of ensuring employment for musicologists.) After nearly a hundred years it still doesn't seem to have caught on with the people at large.