The complex nature of hearing has me baffled, so I’m clutching at straws here a bit. I agree that it would seem, that to cut out a very narrow frequency band would be analogous to zapping a small area of the retina with a laser, leaving almost all the field/range unaffected. I have a feeling that the loss to hearing would be a little more holistic in nature than a small glitch in a digital circuit.
Firstly, the eye, however miraculous, has a massive cluster of nerves leading to vast processing areas. Hearing however, seems to function more simply...until its true functionality is assessed. In short, it seems to perform its own miracles, but with less kit. One of the times that this is displayed, is when a person who has been blind from birth, and has only one functioning ear, can construct three dimensional models from this seemingly limited input.
At a more simple level, I am astonished by the improvement that I get by cupping my hand behind my ear when listening to hi-fi...it sounds a good as I can ever remember. What process is taking place I do not know; it isn’t just forcing more pressure waves into tunnel, that’s for sure.
I have a gut feeling that the only way forward–at least to good recovery from the tinnitus, will be to revive the compromised hairs/cells that are still recoverable. Anything else will be a compromise, and not just a gap in the hearing range, but a difficult to assess degrading of the whole holistic image that the brain constructs.