I think your first idea is really nice; its still pretty early in the year, but if you think you'll stick to the idea, you should try and brainstorm these three main ideas, like:
● appropriate methods for primary research and what you think would be best suited for your topic
● including a cross-cultural perspective
● addressing continuity and/or change.
Remember, your topic will also likely change a lot, like you constantly be workshopping it to fit the syllabus and stuff. My advice would be to just find something that really interests you, which obviously relates back to a 'problem' within contemporary society. The music idea, is interesting, but what were you hoping to explore in that, is it a particular subculture? i think that would be very interesting, and you'd definitely have good public and personal knowledge about your topic.
A good idea would also be to look at the year 12 syllabus, and look at the in-depth studies that you do, because you might want to base a topic around that.
I don't know if any of this was useful, but good luck!!