Re: Ear Ringing
Yep, over twenty-five years. Don't think about it much, it never affected the critical range for my class 1, but did reduce the quality of listening to good pianos a little.
I think mine runs at around 6,240 Htz. So gives the effect of a mix between a whistle and compressed air.
As I say, most of the time I don't even think about it, although at first, it was very distressing. It followed a very hard year of training on a noisy turbo-prop–usually followed by night line checking.
During this time however, I had an ear infection and it was treated with Terramycin I think. This was corrected or confirmed on an earlier post...two years ago ish. The point being that this antibiotic has been blamed for causing tinnitus. Or, it might have been the infection...no way of knowing.