How do teenagers receive calls in class and text messages with teachers never having an idea of whats going on? Humans have the ability to hear better before the age of 20. This pretty bizarre phenomenon is called ”presbycusis”. We lose our ability to hear higher frequencies as we get older, in average after 20 but it ranges. The high pitch 18 to 20kHz ”special” sound was used by police to move teenage gangs away from shopping centers. Teens started recording that sound on their cell phones and shared it with others via bluetooth or infrared transfers to use them as ring tones. Now when a teenager’s phone is ringing only the young ones can hear it, NOT adults/teachers.
Im glad that teens have used that resource to annoy adults because it does not seem right to play them a high pitch sound just to draw them away from shopping centers. It just makes them look like animals, they are not dogs to react to our whistles. Seems fair now that they use it against adults.