As we age, we lose the ability to hear high frequencies. So if you don't want teenagers loitering around your establishment, blast them with high pitched sounds and they'll go away. Meanwhile your adult customers can't hear the sound and aren't bothered by it. Students figured out that you can use a high frequency sound as your ringtone and teachers in school won't be able to hear it. So much for banning cell phones in class.
Adults can't hear this high frequency ringtone but kids can. Students use the high pitch mosquito ringtone to receive text messages in school so their teachers can't hear their cell phones ring. Clever, huh?Go here to read the whole story and download your own super secret ringtone (assuming you can even hear it). After the jump, you'll be able to hear the ringtone for yourself. I couldn't hear a thing.