do you ever hear non-existent music in the sounds of a fan or motor?
I've been running a desk fan at night while I sleep, and often I'll wake up in the night & hear very clearly what sounds like a song playing faintly outside. it isn't real though, and as far as I know they aren't actual songs. I imagine it's my brain picking up repetitions in the complex noise of the fan & filtering it selectively & somewhat imaginatively. I can hear it slightly better if I focus on it, but only up to a point.