she's every poor boy's dream

I'd read this story a while back about a UK invention called the "teenager repellent," or more properly the "Mosquito Sonic Deterrent Device." It plays extremely high frequency noise to keep kids from hanging out wherever it happens to be placed. This only works because it uses frequencies that older adults cannot hear because their ears have aged. When I first heard about this I was fascinated (it helps that I'm an acoustics engineer).

In a curiously peter pannish turn of events, teenagers flipped this back on the adults by downloading and using ringtones that use the same frequencies. So, the kids can hear the phones ring, can text each other in class, etc. but the teachers and other adults can't hear a thing. When I think about it I get these children of the corn freaky images of the kids taking over, aided by their silent communication.

ear damage. note the arrows showing where the hair cells ain't

for some mildly depressing ageism for the weekend, check out this website where you can download so-called ultrasonic ringtones (I guess ultrasonic is relative to the state of your ears?). They also have a series of high frequency sounds that you can play so you can hear they rate the age of your ears. Optimal human hearing goes up to 20 kilohertz (kHz). Sadly, that number is only valid for young children. Years of mowing lawns and punk rock concerts drop that number dramatically. My secret pride was that I could still hear the 16.7 kilohertz sound, which rated me around 20 years old (apparently I both look and hear younger since I shaved the goatee). Give it a try--how old are your ears?

incidentally, I'm bringing my earplugs to the sonic youth/flaming lips concert tonight.