Schoolchildren have recorded the sound, which they named Teen Buzz, and spread it from phone to phone via text messages and Bluetooth technology.
A secondary school teacher in Cardiff said: 'All the kids were laughing about something, but I didn't know what. They know phones must be turned off during school. They could all hear somebody's phone ringing but I couldn't hear a thing.I'm somewhat skeptical about this. Wouldn't the MP3 format's psychoacoustic compression algorithms wreak havoc with subtleties such as ultrasonic tones?
Anyway, I wonder how long until the Teen Buzz sound is heard in grime records, making the first form of teenage music that's actually (partly) inaudible to elders.