I can hear up to about 16k according to some online hearing test, but I question the accuracy of it. I think it's actually probably lower from another site where you chart out your whole frequency curve that seemed more reliable.
I'm recently going through a bout of tinnitus and hyperacusis, which has not been fun. A few weeks ago I got a new dac that it turns out can't be controlled with hardware volume mixer, so when I was first hooking it up I thought the volume was 0%. Turns out it was actually 100% (because the mixer does nothing), so when I switched interconnects it made all this loud cracking square wave kind of sound and felt like it nearly blasted my eardrums out. After that my right ear started ringing fairly loud I estimated at about 7k. I also have TMJ and chronic eustachian tube dysfunction on that side especially from sinus/allergy issues, etc.
After doing a lot of reading, it seems that even with cochlear damage tinnitus is probably largely a neurological disorder. I was reading some really good website by some legitimate experts (the name of which escapes me at the moment), describing how there are "fear" loops created with the limbic system -- a kind of natural anxiety response first to the initial loud noise, but then perpetuated by the constant "checking" of the tinnitus -- that keeps it all going. So with some mental judo I decided to totally "accept" the tinnitus as a welcome thing, to kind of let it in instead of resisting it (which largely comes from the fear of permanent damage, it seems) and amazingly the next day the ringing was literally like 80% lower volume, and the hyperacusis was much improved also, and continued to improve over the next few days.
I still have some feeling of fullness if I focus my attention there, but the ringing is nowhere near what it was and the hyperacusis is still reduced, also. I plan to see an ENT in a few weeks to find out if there actually is any hearing damage and to get a full workup, but I was really amazed at the results of applying the habituation theory ideas in so little time. The mind is a powerful thing when it comes to hearing, it seems, with all the various placebo (or not) effects, psychoacoustics, etc. I'll try to find that website and post a link to it.
>website: Turns out it was pretty easy --
Tinnitus Retraining Therapy (TRT). The definitive site for. Great info there, I encourage anyone with tinnitus to check it out.