I seem to have the same thing. When I listen to static noise (white/purple/pink) there is a high-pitched zinging on top. It usually goes down when the static noise stops. Sound level does not matter, it is always on top. Also background noise triggers it, wheel/engine noise when I drive my car, wind, fans, fridge motors, etc.
Even tried notched white noise, notched at 10khz where my baseline T is. Still makes that zinging on top of it.
When I have good days the reactive zinging is very low. Sometimes I don't hear it, and I only hear my now very tolerable baseline T and hissing. I could live with that. But then that reactive shit comes up again, and sometimes can stay high for days for no apparent reason.
At night it is mostly low or non-present. I therefore normally sleep well now. It usually starts in the morning, gets progressively worse during the day, and goes down again before or at bedtime.
I think there are two things, my baseline T, and this reactive thing. During the first month I had several T tones, that gradually faded to a hissing and a 10khz T, that some days is quite low.
I am frustrated and baffled by this; still trying to figure out a pattern after five months. I find it very hard to habituate to these fluctuations. I have no control over it; no matter what I do or don't do, eat or don't eat, whether I'm stressed or calm, have slept well or not, supplements, ACV, chiropractor, accupuncture, nothing stabilizes this reactiveness. Grrrr
sorry for the rant. I am mostly able to maintain a positive attitude now, but sometimes have to get it out of the system.