Interviewer: Really! Is that right?
Mark: Yes. And to test this out, actually played the tone for my family last night. My wife and I heard absolutely nothing at all, but our teenage daughters could hear it, and in fact they complained that it was an irritating sound that was quite painful to hear.
Interviewer: Oh no! Well, at the risk of irritating some of our younger listeners' ears, why don't we play the tone briefly now?
Mark: OK, here goes. I'm playing the tone in 3, 2, I...
Interviewer: Have you played the tone yet?
Mark: I just did. Or, at least, I think I did.
Interviewer: Well, I suppose that just confirms that neither of us are under 25!