I've been living with tinnitus for about 5 years now, the result of radiation and surgery to fight cancer. I'm no doctor, but I can tell you for many of us, it does not fade away. I'm also deaf in the same ear, and I never knew (or wanted to know) that you can be both deaf and have tinnitus. Maybe when Beethoven conducted he did hear a song, just not the same one we did.
Everything I've read and been told over the years has said that tinnitus is not something that can be observed or measured. There is no method of diagnosing tinnitus that isn't asking the patient "do you have a ringing in your ears". I don't think there is anything that has stated the cause either.
Living with it, you learn to ignore it. You actually teach yourself to not notice the frequency it's on. Common suggestions for dealing with bad tinnitus are basically calming and relaxing techniques so you can get into a zen state that let's you "program" the mind to ignore it. As you can imagine, this is different for everyone. Some need a quite room and others like me do better with a small about of noise going on like in an office.
Tinnitus also isn't always a constant pitch. Mine will move to match the white noise in a room, or other similar frequency. Running tap water in the kitchen I often stop hearing the sound of the faucet, as my tinnitus matches the pitch after a moment or two. I notice when I stop the tap that I wasn't hearing it because the tinnitus will then shift to something else I do hear.
Once, my PC was overheating so I had it on my desk, right next to my deaf / tinnitus ear. At some point, the case fan started squealing, but I never heard it. It got so bad my brother came in from another room shouting "How do you not hear that!?" I guess it was driving him mad.
I've also done serious damage to my brake rotors on my truck, since I never hear the high pitch squeal they make to indicate stopping is begin done by metal on metal. When they took the rotors off, it looked like a 45 RPM vinyl record.
So, it may be true that fibers in the ear are tuned to frequencies, but I doubt this has nothing to do with tinnitus.