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Too High A Hearing Range

02/12/08

  08:31:02 pm, by Nimble   , 328 words  
Categories: Distractions, Thoughts, Common Sense

Too High A Hearing Range

Adam was wondering about my 17.4 kHz comment...

What it relates to is that there's a device in Britain which uses high frequencies to annoy teenagers away from the premises:

A controversial weapon in the war against antisocial behaviour should be banned, the children's commissioner will warn this week in a move that threatens a new Whitehall battle over 'hoodies' rights'.

The row centres on the so-called Mosquito, a £500 device that emits a high-pitched whine loud enough to drive away teenagers in the vicinity. Marketed as the 'ultrasonic teenage deterrent', it is increasingly being adopted by shopkeepers, local councils and even private homeowners to disperse gangs of young people because it operates on a frequency that can be detected only by under-25s, whose hearing is more acute.

If you want to check out your hearing, you can check out the Mosquito Ringtones site. It's particularly amusing that someone pointed this out, because this relies on the same hearing differences, in this case, to be able to sneak things by adults.

I found through this that I can hear up to 17.4 kHz (I'm fairly sure my headphones are reproducing the even-higher pitches), which is a good 13 years or so out of my age range. 17.0 kHz and below is particularly annoying. This might put me in the range of the Mosquito's output, since it sends out a modulated frequency between 17.5 and 18.5 kHz.

That may explain one of the more annoying episodes I had once upon a time at work, where they put a server in my room that ended up squealing at a particularly high frequency and driving me mad, and I begged and pleaded for the server to be placed elsewhere. Clearly, though, people thought I was crazy, for they heard nothing.

We'll see how this British thing pans out. It's supposed to not be painful, just annoying, and takes a little while to become annoying, etc. etc. but I'll leave such judgment for my first encounter with one.

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