Mine just sounds like an old t.v. is coming on. It's real low in volume, but real high in pitch. it only last for a second and tops out at the end of the key. It definitely sounds like a frequency or electronic kind of sound. It's not from hearing damage as I have had this come and go for 25 years. (I am 29)When I was a kid I used to think it meant someone was turning a t.v. on somewhere. lol