Um... What did you say?

Someone I know has a IPhone app that annoys teenagers. I think that might even be the name. What the app does is it plays a high pitched noise only people 18 and younger can typically hear. In the room of 6 adults 3 could hear it.

I couldn't.

He changed the pitch. One person couldn't hear it but she was aware of something bothering her. 2 others could still hear it.

I couldn't.

He tried another few settings. Only when it got to a certain level was I able to hear the tone. What have I learned? 200 + rock concerts have fucked up my hearing. I worked these things with earplugs in my ears. I thought I had good hearing, but I seem to be missing the high range sounds. I still hear most sounds annoyingly well. But I am missing some of my hearing. I really had no idea.

So if you want to do something without me hearing, do it in a range only teenagers can hear...