these folks are talking about ghost and scared of it,
the fact these guys are not understanding is that we are ourselves ghosts(spirits) in bodies.

Regarding those noises or voices, there is one entire valley full of people hearing these noises, guess what it's electromagnetic surveillance.(check the video below)
http://www.youtube.com/watch?v=JmE4oTXYmf4&feature=share
It was on the news last month, and they're calling it electronic harrassment.