As far as I know, "is it your music" is international English, not proper speech. At least it's not American. I would always ask, "is this your music" or "is that your music"
The distinction between > Is "this" your music?< and >Is "it" your music?< is not really clarified by the word "это" alone. The meaning could be either. Google Translate indicates that "это" means "this" and "it" in Russian is "это". "What other Russian word would you use to specifically mean "this" if it isn't "это"?
I think tgat would be эта but i am just judging from what duo has taught me.
Different question: When I played in an international orchestra "music" was equivalent to musical score. Is the Russian sentence equally ambiguous?