Do you hear that? That high-pitched, tinny tone? I don’t, but then I’m not supposed too. The sound is coming from my daughter’s cell phone, and she can hear it quite clearly. Her phone lets her know that she has an incoming text message, but the ringtone is at a frequency that adults simply can’t hear. That’s because the ringtone is emitted at an ultra-high frequency. These ringtones, known as ‘Mosquito ringtones’, ‘teen buzz’, or ‘adult-proof ringtones’ are clear as a bell to kids in classrooms, but well outside of the hearing range of their teachers.
Most people have an audible range of frequencies from 20 Hz on the low end, to 20,000 Hz (20 kHz) at the high end of the spectrum. There is significant variation from one person to another, especially at the high frequency end, where a gradual decline with age is considered normal. There is, however, one constant: young people overall can hear much higher pitches than adults. Young children can typically hear up to 22 kHz. By age 30, most of us can’t hear anything above 15 kHz, and by 60 anything higher than 10 kHz is virtually undetectable. Websites like Free Mosquito Ringtones offer hearing tests and ringtone downloads, while forcing inquisitive parents to confront the reality that hearing loss is an inescapable side effect of aging.
The hearing range of dogs varies depending on it breed and age. However, their range of hearing is up to 60,000 Hz, which is much greater than that of humans. Mice also hear higher frequencies than humans; their frequency range extends up to 90 kHz. Mice cannot hear the lower frequencies that we can. Instead, they frequently communicate using high frequency noises that are out of the hearing range of humans. The distress call of a young mouse can be produced at 40 kHz. Mice have learned to use their ability to produce and hear sounds out of their predators’ frequency ranges. This way, they can alert other mice of potential dangers without also alerting predators to their presence.
This is essentially the same way that kids are taking advantage of their teachers’ limited range when text messages and emails are brought to their attention through one of these high-pitched ringers, which teachers can’t hear. It’s the equivalent of passing notes in class, with a technological edge. Something of a new-age modern warfare approach to spreading rumors and gossip in the classroom.
This is exactly the kind of thinking that has recently spawned a new application for these high-frequency nuisances. Shops throughout the United States and Europe have long been plagued by teenage vandals who loiter around the entrance and the parking lot, forcing some of the more timid customers to shop elsewhere. Law enforcement can do little to prevent young hoodlums from ‘peaceably assembling’ in public, and ‘no loitering’ signs are all but ignored.
This may explain why over 3,000 have been sold in the UK alone, and the U.S. is not far behind. Many of the aptly named Mosquito™ devices have been placed outside shops, fast-food outlets and transport hubs – all places where owners and store managers feel groups of ‘unwanted youths’ are gathering and hurting business.
Manufacturers of the Mosquito™ claim that it has no adverse effects on children or adults, and that while dogs can hear it, they won’t be bothered by it. They say that field trials have shown that teenagers usually move away from the area within 5 – 20 minutes, and that after several uses, the teenagers tend not to loiter in the areas covered by the Mosquito, even when it is not turned on.
In the UK, civil liberty campaigners have had some success in thwarting the use of these devices, but in the U.S. there is no valid claim for an infringement of First Amendment rights unless and until there is some kind of state action. If the police employed mosquito devices for crowd control, or if public schools used them to disperse students after class, the ACLU would no doubt be salivating at the thought of another high profile lawsuit. No such luck, however, when the only ones buying and using these devices are shopkeepers looking to stay in business in a tough economic climate.
In the end, it’s the store owners who use mosquito devices at their own risk. If blasting the area with annoying high frequency sounds ends up hurting business, then they’ll surely unplug them. Until then, the masses of bored teenagers in search a cool new hangout spot will just have to keep on searching. But for parents whose teenage children turn a deaf ear to repeated requests to turn the music down, karma is a sweet, sweet revenge.