The Teenage Audio Test plays a tone that is generally only heard by people under the age of 25. The high frequency sound has been used keep trouble-making teenagers away from the malls and disturbing shoppers like me with requests for cigarettes or money for “school books”.
Take the Teenage Audio Test. If you heard the sound and are over 25 years old, then pat yourself on the back for you have the hearing acuity of an ass-hole teenager ;)