I've noticed that tinnitus researchers often talk about the frequency of tinnitus being at a dip in the audiogram (in some people). It's then said that tinnitus, therefore, occurs at the frequency of a hearing loss. Even if I could be said to have an area of expertise, tinnitus research wouldn't be it, but it's certainly an area of interest for me and I am someone with tinnitus who has done several audiograms. On my audiogram there is a dip around the frequency of my tinnitus, but I suspect this dip is due to masking of the tone or warble used rather than necessarily being indicative of a hearing loss. I'd be very interested to know how people make the distinction between masking by tinnitus and a hearing loss.