An article in "Dutch", can't find the English yet, about a German research into the treatment of Tinnitus by:
Playing (listening) to music with the specific frequency of the individuals tinnitus filtered OUT (from plus 1 to minus 1 octave from center freq.). Listening in this manner causes stimulation of the neurological functions in the brain around those frequencies which should be, but are not there. This in turn helps with the patients tinnitus.
There was supposedly an article in the "Proceedings of the National Academy of Sciences" but haven't found it yet. Meanwhile, here's the link to the Dutch Article:
Dutch language newspaper article