Oops! I'm a musician who reads music, and I always have trouble hitting the right 'clicky thing'. So much for the 'brilliant' hypothesis! Sorry...
I just wanted to respond to GUEST above that yes, other species on earth do have their own 'species-specific' music, most of which I enjoy very much. But we ARE the only species that creates and plays instruments, or who has evolved a system of writing our music down, recording it etc. Why would we have this ability, or be inclined to use it so extensively if we don't need it?
I think that music is indeed 'necessary for human survival", just as bird songs (mating calls) are necessary for their survival, as a species. We just don't understand how or why. Yet.