If you love to hear music really loud and when you sleep nothing can wake you up. I suggest you to take this little test to see how good or bad your hearing sense is.
Just click the play button.
Did you hear it?
If you did, congratulations!! Specially if you are over 25 years old because supposedly only people younger than this age can hear it. This tone has been used in shopping malls and stores as a deterrent device to keep teenagers from loitering, as it seems, the longer you listen to it, the more annoying it gets.
Note: I’ve applied this test to my mom (she’s 53 years old) and she didn’t hear it, I also tried it on one of my sisters (19 years old) and she did hear it. So far the hypothesis is true.