this is crazy! I could hear everything above 17.4khz - 24 & younger. Not bad for a 40 year old! My 6 1/2 year old son could hear all but the 22khz. He said it made his throat tickle though. Max my 4 1/2 year old could hear them all and giggled.
i could just make out the 17khz but nothing below, but i don't think i'd hear it unless i was listening out for it ... i blame the edge in coventry for my dodgy hearing