I couldn't hear it at the normal volume that I can hear my other computer noises. I had to turn it all the way up. I initially answered "What noise?" because of that.
A lot of kids have made noises in this spectrum their ringtone for their phones at school because most of their teachers can't hear it.
This one is a little better test. I can hear 11 and 12 very clearly at low volume. I can't hear any of the others.
http://journal.plasticmind.com/ears/...ure-a-youngun/