Teenagers have a new ring tone that adults cannot hear, because the frequency is too high: 17 kHz.
Test it with Audacity:
File / New
Generate / Tone… Frequency: 17000
Play it.
I cannot hear it. But I can hear a 14 kHz tone.
The ring tones are appearing on the net: here and here.
Analyzing the first one with Audacity (Analyze / Plot Spectrum) reveals a peak at 15 kHz.
Keep this in mind when testing:
- your hardware (sound card, speakers, …) must be able to handle the frequency (20 kHz is a common limit)
- when exporting as mp3, select the right sampling frequencies (Nyquist)
Didier Stevens 
I suppose at the ripe old age of 31 I am a certified geezer. I read your post at a client’s site just before one of the other programmers tried to play the tone for me. If it wasn’t for your article I would still think he was trying to trick me. (You have to watch out for those wiley 26-year-old whipper snappers!)
Congratulations on starting your blog! You know I am a subscriber š
Comment by Craig Shoemaker — Thursday 15 June 2006 @ 14:39