try this music and the brain article
courtesy of proven by science -- many of the conclusions come across as things that you and me could've been aware of but its a starter on the topic, and quite a different take on the 'why music matters us' question.
But it also may, in turn, tell us more about how our brains have been rewired over the course of the 20th century. One in which we've discovered new ways with (among other things) timbre . Most of the research up to now has, understably, centred on melody.