I heard everything at 42 years old. i actually though my hearing was going bad. Probably still is.
Anyway, I did have to raise the volume on the last 2 tones. Is that cheating? lol I have old Dell 2.1 speakers. I raised them at least halfway to max on the last two..
Interesting, I heard 16 clearly, but 15 was barely as noticable. Maybe different frequencies affect us differently? Ot perhaps my speakers or room is causing that? Either way, I went from top to bottom, and when hearing 15, I said to myself, "Oh, this is going to get harder...." but 16 was much clearer. Nice. Thanks for the test.
Maybe that's why I think my HT system is 'bright'. AHA!!!! lol Well, maybe.