Most humans are born with the ability to hear frequencies from about 20 Hz (low) up to 20,000 Hz (high) but that range shrinks as we get older.
Linked is a 20,000hz sound file (http://download.npr.org/anon.npr-mp3...c_teenbuzz.mp3). Make sure your speakers are on and your sound is unmuted. When you play this file, listen carefully for a high-pitched sound. If you can't hear it, you have some hearing loss!