"Mosquito" ringtone, can you hear it?

[Rock&Roll Ninja]

Some company or another creates a 17KHz tone which is supposed to repel teenagers (so they stop hanging-out in front of the 7-11). Older people don't hear as well so, suposedly, most people over 20 can't hear it.

Annoying teenagers then take said tone and use it for a cellphone ringtone, so parents, teachers, and adults in general can't hear it.

Heres the tone played twice: http://www.jamster.co.uk/storage/view/325/1/ma/Magic_Sound_16.mp3

I'm 27 and I can only hear it if my computer speakers are ALL the way up, and I'm within 3 feet of the speakers. I guess CDs 20,000Hz ceiling limit would be lost on me, eh? (saying nothing of SACD's 40KHz limit).

PS: Its really annoying if you can hear it.

 

[racquetman]

They had a segment on this on the morning radio show I listen to. They had said that students were using it in the classroom because they could hear it and their teachers couldn't. I don't know why you need a stealth frequency when you can just put the thing on vibrate - not to mention why the heck students need cell phones in the classroom anyway.

Whether you hear the sound or not is also going to depend on your speakers, as many of the poor computer speakers out there probably aren't going to output that frequency very well. I heard the "noise" easily over the radio, but when I listened to the podcast of the same segment on my computer speakers, I couldn't hear it.

 

[pbarach1]

Depends on the speakers

I'm 27 and I can only hear it if my computer speakers are ALL the way up, and I'm within 3 feet of the speakers. I guess CDs 20,000Hz ceiling limit would be lost on me, eh? (saying nothing of SACD's 40KHz limit).

I can barely hear it on my computer speakers, but I hear it quite clearly my home theater system. How come the speakers in cell phones have enough high frequency range to play 17kHz??

 

[10010011]

If you can hear the horizontal oscillator in your TV then you can probably hear the ring tone too.

TV horizontal oscillator = 17750Hz (if memory serves me correctly)

I can barely hear it on my computer speakers, but I hear it quite clearly my home theater system. How come the speakers in cell phones have enough high frequency range to play 17kHz??

Because they are teeny tiny little piezo devices that reproduce high frequencies with ease.

 

[Audioholics]

I don't know why you need a stealth frequency when you can just put the thing on vibrate

Vibrate actually makes noise.

 

[annunaki]

I can easily hear that tone, and, it physically hurts if you are close to the source.

 

[Rock&Roll Ninja]

Found a different site with samples from 10K upto 25K.

This time I kept the volume steady (the same I use for casual music listening) and used my Sennheiser headphones. I could hear 16K, but 17K gave me a headache (even though I couldn't process the "sound").

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

 

[CaliHwyPatrol]

I heard up to the 24,000hz, but I didn't hear the 25,000.

And that is a cool fact about the tv ocillator frequency. I've always wondered why I can hear the hum from tvs when some people can't. I can tell when a tv is on even if there is nothing on the screen, and a most other people who I know can't. I guess I'm not an alien afterall!

~Chuck

 

[Mudcat]

I heard up to the 24,000hz, .........I guess I'm not an alien afterall!

~Chuck

Obviously you're not a motorcycle patrol because they cannot hear past 12k.

But, if you can hear a 24k Hz signal, your are an alien.