This is officially the sound that only people under 30 can hear. Try it! 
[youtube]http://www.youtube.com/watch?v=U_GrIzcxClM[/youtube]
I’ve already tested it on my parents.
Great success.
Drats. Nevermind.
I guess I had the volume too low because now they can hear it…
There are people in the comments saying they can’t hear it though.
They fit that shit in alarms around shops and houses to deter kids from hanging around. I’m sure my neighbour had it too, the most annoying fucking thing ever. And we live at the bottom of a cul-de-sac!
What sound?
I’m 32 yet I can hear it.
No Saully you’re just getting delusional with age. You don’t hear a thing! Now go back to your lounge chair, the price is right is on.
Ok ok, actually all this proves is that you still have good hearing, because I saw some 13 and 14 year olds complaining that they couldn’t pick up on it and 50 year olds who could.
Maybe its if you can hear it, you’re too young.
Yeah, the title seems to be a bit off. On purpose?
What title?
Hilarious.
Played this sitting next to my best friend’s daughter, Annaleise, who is 11, while my best friend (who is 32) was 5 feet away from us in the kitchen. When Annaleise said, “What is that noise?!” and the dogs started barking, Bitchface (aka Heidi, aka my best friend) said, “What is what noise?”
hehehehehe 
Now I get to make fun of her. Thanks, Echo 
…was it that kinda squeaky squeal? I heard it, I heard it 
It hurt my ears. Never again.
I’m 31 and I can hear it and I’ve had sinus surgery and clogged up tubes in my ears and have been shooting guns and riding motorcycles and playing the electric guitar since I was a kid. I’m practically deaf in my left ear and I totally heard it.
[+1]
I can’t hear it. Therefore it doesn’t make a sound.