On 09/03/2015 20:49, Trevor Wilson wrote:


MORAL: With sufficient intensity, human hearing can extend way past
20kHz.


I wouldn't exactly call the sensation of a high level 20 kHz tone
'hearing' more like 'detection'. My normal hearing barely extends to
9-10 kHz these days but I was aware of an odd clicking sensation (best
way I can describe it) in an a relatives garden. Turned out to be a cat
repellent gadget. Sensation vanished when it was switched off.

I've also been aware of a vaguely uncomfortable feeling standing close
to a shop window that had some sort of 'anti-teen' sound device
installed. Couldn't hear anything at all...just an awareness of
something unpleasant. And I'm no teen.