Go to this link
and if you have speakers put your mouse on the file and a countdown starts from 22 to 11 (22khz to 11khz).
When you start hearing a high pitched noise the number on which you hear it reflects how good your hearing is.For instance,if you are younger than 25 you should hear up to between 17-19khz , under 20s may hear higher.
When your ears ring its a frequency dying in your ears. So when you get ringing it means that there are certain frequencies that you will never hear again.
I was 16,which i think could be average for a 29 year old.Basically the higher number you hear the noise the better your hearing is.