Mine is a deep sinus tone around 50-60 Hz. The amplitude varies between the days/sometimes between the hours. Pretty annoying, even though it's most prominent in quiet environments, and I can imagine having a loud high pitched tinnitus would perhaps be worse.
And on the main topic, i occasionally have ringing ears, and about 90% of the time i know why (usually a loud engine that i wasn't wearing protection near), but 10% of the time, like during a quiet weekend at home - it appears out of nowhere. I am not sure what my frequency is, but it's well over 1khz.
