Status: Undetermined
I've received quite a few emails about this. A British paper,
metro.co.uk, reports that resourceful teenagers have devised a way to make the ringing of their cellphones inaudible to adults. The trick is that they've recorded the sound of the Mosquito, which is a device that emits ultrasonic tones inaudible to most people over the age of twenty-five, but quite audible, and rather annoying, to people under the age of 25:
Techno-savvy pupils have adapted the Mosquito alarm, used to drive teenage gangs away from shopping centres. They can receive calls and texts during lessons without teachers having the faintest idea what is going on. The alarm, which has been praised by police, is highly effective because its ultra-high sound can be heard only by youths but not by most people over 20. Schoolchildren have recorded the sound, which they named Teen Buzz, and spread it from phone to phone via text messages and Bluetooth technology. Now they can receive calls and texts during lessons without teachers having the faintest idea what is going on.
Can this be real? Well, the Mosquito is real enough (I posted about it back in
November 2005), and it is true that young people can usually hear higher frequencies than older people because we lose the ability to hear high frequencies as we age. The question is whether cellphone speakers can generate these ultrasonic frequencies.
Boing Boing posts a comment from one of their readers who swears that cellphone speakers would not be able to do this. However, another reader links to an
article that contains an
mp3 recording of the Mosquito sound. (When I listen to it I can't hear any high-pitched noise, just a bunch of street noise.) So if computer speakers can generate these frequencies, perhaps some high-end cellphone speakers also can. Seems plausible. In other words, I'm not yet willing to label this story as a hoax or false rumor, even though it does seem to be a bit far-fetched.
Comments
Regarding a cell phone's capability to render a tone outside most people's audible gamut, I honestly doubt it, as per JS's comment on Boing Boing. Mind you, I'm not saying you can't encode that into an MP3, I'm only saying I doubt the phone could play it.
I reckon that there is truth behind this.
If I was trapped in a room full of cellphones making that noise, people would die.
And yes, I also needed to turn up the volume. But I realized I only needed to turn up the volume as to make the street noise sound "natural" -- that MP3's level is lower than your average sound file's.
I'm slightly over twenty and i can even hear the lowest frequencies of a bat (not the actual hunting frequency, but the 'powering-up' sound), although it gets less clear every year.
(It is really annoying when you're doing a lab experiment about frequenties: 20.000Hz, loud enough for a frequency analiser, hurts a lot when you can hear it clearly)
Being able to hear such high frequencies is also a bit genetic, I think. My father could hear the frequency of television tubes (16.000Hz) up to his mid-fourties. While a younger friend of mine can't even hear it now.
About the speakers, some high-end ones go up to 48.000Hz, but thats not the actual reading, but it has something to do with richness of sound or something. (Should ask an audio-specialist or so)
Also, I could only hear it in my right ear....so facing the speakers, I hear it fine, turning to the left so that my right ear faces the speaker, once again I hear it however, turn to the right so my left ear is facing the speakers and the sound magically disappears.
To me it sounds like the worlds most annoying cricket. (much higher pitched than a crickets "chirp" but thats the closest comparison I can come up with).
Also, MP3's are compressed by removing frequencies beyond the hearing range of most humans, whether or not the frequency "The Mosquito" uses is one of those, I don't know.
This is a spectrogram of the tone in it.
I am 36 and hear it without trouble when I somewhat turn up the speaker volume. A very high-pitched, somewhat chirping tone.
This worries me that people like me who have full time jobs and never hang in gangs and work for a living will be chased away from places that we have a right to be in.
At any rate, since some phones have sound system intended to play back mp3's then there is no reason whatsoever why it cannot be used as a ringtone.
Of course since some teachers are around my age, those using it in this manner are likely to be caught, sooner or later.
Sounds just like my old cheapy TV set.
Even now after I've turned off the MP3 my ears are still ringing.
not that i don't believe you all, but probably my speakers just couldn't handle it. they are crap.
I'm 18 and i've got some seriously good hearing, regardless of the fact that i blast my music-etc.
I'd have to say though, if someone played that tone in a confined space and i couldn't switch it off, i'd go insane pretty darn quick. It's so darn hi-pitched!
I need to clean up the audio file a bit but i'm thinking about using this to deter yobs from my local stores whenever i go to pick up the paper or something. It'd be good to use if i had some headphones or earplugs to block the sound out with.
Methinks it's time for a little mayhem! :D
It hurts my ears - little stabby pains. He says he feels it more than hears it and it seems to sorta resonate through his sinuses. We agree it's quite annoying.
It's quite possible that the sound as heard in an mp3 differs substantially from the original. In any case, I find the product concept distasteful and wish adults would quit trying to drive teens away from public spaces whilst providing no alternatives for entertainment or socializing.
Is it the same sound that comes from general electronics? I go crazy hearing that.
http://syslog.eu/index.php/2006/05/29/ucitele_neslysi_vyzvaneni_mobilu
I am able to hear 15 kHz.
On the assumption they weren't hoaxed, it's possbile. The phone speakers just have to be up to the job.
i do have to turn up the sound to hear it. its more of a sensation than a sound. i used to get this a lot with tv sets and monitors.
i haven't tried this on a phone, whether it works there is another story. however, the sound is very undirectional and would easily be muffled by pockets.