I mostly only hear sounds like that if im listening to music. Or if im paranoid, ill think that I hear my friends talking about me. There was this one time when i was trippin like mad off shrooms and I thought I heard every sound of everything falling at the same time. It was freaking the fuck outta me too. I didnt know if i was hallucinating it or not, like everything else I heard. But then again that was shrooms and they do that.