I knew about this a while ago, but it wasn't until I happened upon DavidOrr's blog and read this blogpost that I was reminded of the Mosquito Ringtone. And now I want to bring it to you and make you aware of it too.
What is this Mosquito Ringtone? Back in 2005, Howard Stapleton created a device that emitted a extremely high pitched sound. The sound was played at 17.4 kHz. The device was set up outside of a grocery store. The result? Teenage loitering dropped dramatically in the area.
So how does it work? The human hearing range goes from 20 Hz to 20 kHz. As people age, their ears experience damage over time and the hearing range drops. The frequencies to drop out of the range are the higher frequencies as the ear gets less sensitive. By the time most adults are in their 40's, the highest they can hear has dropped down to 14 kHz. Most people under 25 can hear frequencies up to 17.4 khz. So what happens if it's out of your range? You just can't hear it. All the time, birds chirp in ultrasonic frequencies to communicate, yet we are unable to hear them. A dog whistle works in the same manner.
This fact was utilized in creating the Mosquito Ringtone. The device, marketed as the Mosquito, is designed to help deter teenage loitering in public areas in curfew hours. Namely gang loitering that would disturb business. By using the device, the high frequency sound at 17.4 kHz and at a very loud 85 dB is heard by almost everyone of ages under 25, and not at all by those over that age. This was proven many times to deter people of the target age from congregating in the places where the Mosquito was located.
Being marketed worldwide, it has met with opposition though. Some say that it infringes on the rights of people. Others cite the harmful effects of ultrasonic sounds. Namely, ultrasonic sounds disturb the equilibrium mechanism in our ears and can cause disorientation, dizziness, and headache. Also, adults who can't hear the frequencies wouldn't be able to protect their young children and infants who can hear the frequencies. Some cities have banned the use of the device.
Of course, any thing like this can be turned around. Recently teens have figured out that with a sound that adults can hear, they could use it as a ringtone to bypass school disciplinary action. Being marketed as the Teen Buzz, it is a high pitched ringtone designed for teens to hear only. Sounds like fun to me. :3
More information can be read about the Mosquito Ringtone here.
You can tell your ear's "age" by the frequency that you can hear at. So come one come all and test your hearing!! :D Below are the listed frequencies and their corresponding "ages" and a video to test you out. Have fun, and post your hearing age! :D
If the highest you can hear is....
22 kHz - Superhuman. :D
20 kHz - Your ears are as fresh as a baby's.
18 kHz - You've got the ears of my grade school brother! *gasp*
17.4 kHz - You're younger than 25. Majority of NG falls here. :P
14 kHz - You're in your forties. Want to buy a Mosquito for your teenage kids? :3
11 kHz - You're in your fifties. Retirement's around the corner. Might I suggest the Oldies section?
8 kHz - Well.... your ears.... work. That's about it.
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Have fun everybody!
-HFX ^_^
P.S. I can hear up to 19.8 kHz! :D My hearing's nearly a newborn's hearing! :D