It's probably possible, given a good computer to manipulate the sounds with.
Musical hallucinations.. hmm. Do they get distracting? Or is it more like having theme music? Anyway, it's not a problem if they're not distracting and you know the music's being produced by your brain and not your surroundings.
I notice sounds that nobody else notices, but they're not hallucinations; they're just things that other people filter out. For example, the hum of the fan on a CPU, the high-pitched whine of a charging battery, a vacuum being run next door, the builders across the street using hammers, my cats walking across the floor, my own heartbeat.... I have a lot of trouble with that because I live in an apartment, and that means noticing everything the neighbors do. I can tell by the sounds when they're cleaning or letting the dog out (she's not a barker; she just has a unique footstep) or showering or going to work... I just don't filter this stuff out. It really gets annoying sometimes because when I try to concentrate, I hear all those noises and I can't seem to shut them out.