http://www.npr.org/templates/story/story.php?storyId=5483203&sourceCode=gaw

"On the front page of yesterday's New York Times, "A Ring Tone Meant to Fall on Deaf Ears." It's about an invention from Britain called the Mosquito Teen Repeller, a device that sends out a high-pitched tone that most adults can't hear (audio). The intention was to disperse groups of teenagers with the annoying noise, but youngsters quickly figured out how to use the high frequency signal as a ringtone for incoming cell phone text messages. Kids in classrooms could hear the tones, but the older teachers couldn't."


I downloaded the ringer for my phone and it is hilarious. I can hear it crystal clear (and extremely loud), but adults i've showed it to cannot hear it or can barely hear it.

Brilliant!

Hmm... I could hear it. I do not know how loud it would be on a phone though. I do not know if it was me, but it seems the frequency increases throughout.

I'm 21... does that count as being young enough to hear?

I think they got the idea from TVs doing it sometimes. I remember in high school our English teacher would sometimes leave the TV on before playing a video clip. A handful of students (maybe 20% of the class, myself included) could hear this high pitched sound (almost like this ringtone) that the teacher couldn't hear even if she put her ear up to the TV... and 80% of the class just thought we were crazy.

Hmm... I could hear it. I do not know how loud it would be on a phone though. I do not know if it was me, but it seems the frequency increases throughout.

I'm 21... does that count as being young enough to hear?


On my phone it is super loud.

I'm not sure about the frequency increasing --to me it stays pretty constant.


21...old? God i'd hope not. If someone is 21 and can't hear it, it must mean that they've attended too many concerts or listen to music that is WAY to loud.

I'm listen to music pretty loud and abuse my eyes with video games... I am suprised those two senses still work.

27, I can hear it.

Audiophile. :D

- N

What frequency is it at? I would assume it is around 20,000 Hz.

That's a nifty idea. It would be particularly effective against the older teachers, of which there are many.

What frequency is it at? I would assume it is around 20,000 Hz. It doesn't even need to be that high. Hell, I can't even hear a 20KHz sound. Only about half the people I know can hear the 17.5Khz horizontal oscillator on a TV.

It's a clever idea though.

http://www.bbc.co.uk/wiltshire/content/articles/2006/04/04/mosquito_sound_wave_feature.shtml
http://www.ochenk.com/entry.php?id=63

Downloading test files from the internet won't give you an accurate representation of your hearing range because of the wide variation in speaker quality, soundcard quality and sound formats used. To get an accurate result you need to get your hearing tested using professional audio equipment.

yea, the same tv sound, just easier to hear, I think it's because of my 5.1 speakers.

both me and my mum can both hear it at 15000

Welll I'm 36 and I could hear it loud and clear too; incredibly screechy pitch (really painful at a high volume); could hear it ringing for some seconds even after it had stopped

So what does that mean?

*tried redarmy 11 other link; I go deaf at 21000; is that good or bad?* :)

that the test does not work because our speakers are crud quality

The bbc one made my head ache... auch

I wonder if this can damage your hearing... That repellant is quite offensive.
Maybe those kids should get a lawyer.

http://www.ochenk.com/entry.php?id=63

Using that site, 20k is my max. I can hear the 19k one, but for the 20k, I can barely tell something is in the background with a soft hum. If other sounds were thrown in, I wouldn't be able to hear it. I couldn't hear anything between 21k-25k, other than the obvious start up and ending pops, heh.

- N