I like the idea but I think it can work better. since we can't hear, we can use some visual elements to represent the beat, say when you buy some instruments, they will show around you, and they( and you ) will animate based on the beat. I think that would add some flavor to the game.
I think some bmg is still necessary, even some noise. or sometimes you can hear a clip of the music.
anyway I like the idea, keep going!