What's that Buzzing?

The so-called mosquito ringtone is a Welsh security company's invention. It is a high-frequency sound that older adults can't hear because of presbycusis. Originally designed for shopkeepers to discourage teen loiterers, the sound was appropriated (allegedly by some enterprising students) and turned into a cell phone ringtone that adults can't hear - a useful feature in setting such as classrooms, where sending and receiving calls and text messages by cell phone is banned.

The ability to hear sounds above 8 kilohertz (kHz) diminishes with age, typically starting in your 40s. The mosquito ringtone is available at ranges between 16.7 and 22.4 kHz, which usually only people younger than age 24 can hear.


from Hearing Health Magazine, Summer 2011