I have had a look at sound therapy. I've gone as far as checking out one of those online noise generators. My ring seems to be tuned to about 9 kHz. A disappointing side note is that my high-end hearing doesn't go a *lot* higher (I guess I should probably be able to save money I might be spending on better gear). The idea, as I understand it, is that if you feed your ears a pitched noise at the same frequency, your brain and/or ears will *stop* creating the ring, which it supposedly does as compensation.
I tried it at work the other day. I share an office with a coworker. So I was using the noise generator through some very nice isolating headphones my employer provides to me. I tweaked things till I found what seemed to be the right frequency and turned it down to be barely audible. It did seem to have interesting effects on the ring. But then my (younger) office-mate wags his hand in front of my face to get my attention.
He says, "What is that you're listening to?!".
"You can hear that?", I ask.
"Oh, yeah, it's really loud!".
"You hear it through my headphones?"
"Yeah, I can step out of the office and hear it out in the hallway".
"You hear it right now?"
"Definitely"
I heard nothing.
Then I turned if off.
"How 'bout now?"
"Nope"
"Well, now *I* do"
Hmm.