[maw]

Interesting question. I think there are some. Does N hz "sound like" N*2 hz and N/2 hz across cultures? I expect the answer is yes, but I don't really know.

Have a look at http://www.youtube.com/watch?v=A13_QGMtlRE. I think Bobby McFerrin would say that there indeed are music universals.

[emillon]

It does. You can view any 2*N Hz signal as a N Hz signal with a doubled period. So two such signals will keep "in phase", and when you mix them it can compose a new coherent sound.

[jtheory]

The "counter-proofs" to music universals is often just presenting an example of music from somewhere that doesn't match the universal in question.

Counter-example don't disprove trends, though, and there are certainly trends (I think "universals" is just not quite the right word).