Riddle Me This Batman; Low Frequency Hum: SOLVED

many years ago I heard of people with certain types of fillings in their teeth would have radio stations and music in their heads. Not sure if that is the same with you or not. And when I was in the Navy my ship had a fathomator and I was the only one who could hear it ping and answer no less. one night out of a deep sleep the ping increased, don't know if a sub or a whale went under the ship. sorry but at least I knew what caused the noise in my head.