Music recommendations algorithms are a fools errand. If you look at Spotify, they do a good job initially but it gets really boring after a while. All algorithms or AI tries and usually fails to guess how you are feeling at that moment, maybe there was a trigger for me to hear a specific type of music, or maybe I suddenly feel nostalgic and want to hear 90s music instead of my favourite modern electronic which I skipped a whole tone if it comes up.
You could still use collaborative filtering, except with users giving different ratings to the same songs depending on their mood. This approach was used in a movie recommendation engine (I forget which one).
