PDA

View Full Version : 18000 Hz


NOFX
06-01-2006, 06:08 AM
Pupils perform 'alarming' feat
Wednesday, May 24, 2006 (http://www.metro.co.uk/weird/article.html?in_article_id=14031&in_page_id=2)

A high-pitched alarm which cannot be heard by adults has been hijacked by schoolchildren to create ringtones so they can get away with using phones in class.

Techno-savvy pupils have adapted the Mosquito alarm, used to drive teenage gangs away from shopping centres.

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.

A secondary school teacher in Cardiff said: 'All the kids were laughing about something, but I didn't know what. They know phones must be turned off during school. They could all hear somebody's phone ringing but I couldn't hear a thing.

'One of the other children told me all about it later. I couldn't be too cross, because it shows resourcefulness.'

The Mosquito technology is said to play on a medical phenomenon called presbycusis, or age-related hearing loss.

It is thought to begin at 20 and first affect the highest frequencies – 18 to 20kHz.

The device was developed by Merthyr Tydfil-based Compound Security.

Boss Howard Stapleton said: 'I think it is a giggle. A teacher would be able to hear the sound only from 1m away. Teenagers could hear it from much further away.'





Here's the tone in case anyone wants to see if they can hear it.
http://lm2005.googlepages.com/highfreq1.mp3
http://files.redvsblue.com/TeenBuzz.mp3
http://www.savefile.com/files.php?fid=6469525
http://www.megaupload.com/?d=0XJENM4F
http://www.wikiupload.com/download_page.php?id=3849

The website for the company that produces the Mosquito: http://www.compoundsecurity.co.uk/

I can hear it a bit on the first link but not the second. Weird too... I hear the high pitched white noise from nearly everything electronic in the room.

Also, it's been pointed out that at least some cell phones aren't capable of putting out frequencies this high. I've seen some people say some phones can or if you mess with the phone you can play higher frequency sounds. Also, it seems at least some people are saying you can't hear it or can't hear it well on the computer, but if you put the tone on a phone they can hear it.

SiGSR
06-01-2006, 06:18 AM
Is this a joke? I can hear the first one as well, but not that second one. If I turn up the volume a can hear a long noise, but I can't hear it on a normal level. What's it suppose to sound like anyways?

NOFX
06-01-2006, 06:20 AM
It's not a joke. It's just a high pitched tone. You should be able to see it in some media players that have video displays to go with the music.

Some people can't hear it, some can. It doesn't really seem to matter much how old you are though it's more likely you'll be able to hear it if you're younger.

SiGSR
06-01-2006, 06:28 AM
It's not a joke. It's just a high pitched tone. You should be able to see it in some media players that have video displays to go with the music.

Some people can't hear it, some can. It doesn't really seem to matter much how old you are though it's more likely you'll be able to hear it if you're younger.

Oh, if it's just a tone, I can hear it if I just turn up the volume on the headphones.

Do you experience more hearing loss from extreme low freq, or high freq?

tienr
06-01-2006, 08:36 AM
wtf, i can't hear the first one, but i can hear the second one clear as a whistle

LowNotSlow
06-01-2006, 09:38 AM
holy shit that is a grating sound. I can hear them all.

rei
06-01-2006, 12:49 PM
hmm I heard them.. but yeah like you said, I hear stuff like that coming from electronics all the time..

Arcane Hayter
06-01-2006, 02:17 PM
Yeah, its really wierd when you turn the lights off in a room and you hear that certain whine of electricity still flowing through something you thought was turned off. I notice it with my monitor, my DVD player and my DirectTV receiver the most.

Killa_CiViC
06-01-2006, 02:24 PM
I'm 25... I couldn't hear it.... I turned up the volume on my computer a lot so I could try to hear it, and my girl (who is quite a bit younger than me) came in asking "Wft is that noise?" :lol:

So it works...

96 DX Hatch
06-01-2006, 02:25 PM
I hear a lot of burrrrr shit, but i can also hear the pitch. Weird :lol:

vandynamics
06-01-2006, 03:09 PM
i can hear them all. my dog was like WTF

T!mmy
06-01-2006, 03:43 PM
mom and dad (mid 40s) couldn't hear a damn thing ever

me (18) can hear it across rooms no problem
younger brother (13) hears it perfect as well haha

NOFX
06-01-2006, 04:43 PM
I can only hear the first one if I turn up the volume really loud and then I can also hear the sound of the speakers which is annoying by itsself. I can't hear the second one. I didn't try the other ones yet since Jason was sleeping when I poested this last night. I had to use headphones.

My head kind of hurts when I hear the first one at normal volume, but I still can't hear it then.

That's okay though. I have a really sensitive sense of smell. Seriously... it blows though. I can get sick from the smell of food cooking. Food I like even. :???:

I just thought this was pretty cool though.

I don't hear the sounds but for example, Jason leaves his DVD player on all night and it keeps me up sometimes so I have to turn it off.

Wolfy
06-01-2006, 10:39 PM
I can hear all of em... but not surprising since the military said I had clinically perfect hearing. :lol:

slammedSI
06-02-2006, 01:05 AM
FUCK it hurts my ears, i herd them all and im 21, i listend to them about 5 mins ago and my ears are still ringing for some reason.

radarblips
06-02-2006, 01:12 AM
FUCK it hurts my ears, i herd them all and im 21, i listend to them about 5 mins ago and my ears are still ringing for some reason.
:werd:
I turned 20 this year in march
I can hear them..
this fucking whine in my ears is annoying