I've had a general high-pitched sound with me for as long as I can remember. I don't know if I was born with tinnitus or if it's just the sound of my nervous system.
John Cage loved to tell his anecdote of stepping into an anechoic chamber in an attempt to hear actual silence. He told the technician that he could still hear two sounds, one very highly pitched and the other very low. The tech told him that the high sound was his nervous system while the low was his circulation.
Cage had a similar story at his last DC appearance in 1991. At a different concert of his music where the sound was amplified, some patrons complained about the high volume. Cage checked it out for himself, putting each ear against the speakers "like a toaster" (IIRC). His ears rang for several days. On his way to the doctor the ringing stopped. I wish I could remember when he said this took place (he was 78 in '91).
