Here is what I hear 24/7/365...
http://www.youtube.com/watch?v=1u_8Qg1npAM
It is loud enuff to drown out baying dogs less than 100 yards into the woods...
It drowns out, nearly completely, the ceiling fan with a wobble and noise I used to rely on to help me fall asleep... Now I have to have the TV on for at least 1.5 hours as I am also insomniac that I may need that much time to finally fall asleep deeply enuff that the ringing don't wake me when the timer cuts off the tv...
Never tried to protect my ears from gunfire, explosives, un-muffled engine noise etc...
Once you damage them... it is too late...
Brent