I should clarify. By hard to classify, I mean with same tools that common practice period music is analysed with. Genres like modern rock, metal, rap, and lots

I should clarify. By hard to classify, I mean with same tools that common practice period music is analysed with. Genres like modern rock, metal, rap, and lots of electronic genres are hard to study using those same methods. I suspect it's partly because they don't have as much harmonic complexity as CCP music and focus a lot more on timbre, but also because it's just unfamiliar to teachers.