I don't care what the music is. I don't want to be in a stall trying to take a shit, and having to listen to the guy in the stall next to me making weird bowel noises.
I think some form of sound or music can drown those fart and poop sounds out. I think this is a pretty simple solution to a huge problem.
Of course, there are logistics involved in getting music in the bathrooms. It's probably not possible for ALL public restrooms to get music, but I'm sure an office building or something can afford it.