It's a tone that middle aged and older people supposedly can't hear so youngsters are using it as their ringtones in class!
Warning: If you can hear this, it's highly irritating.
Via Huffington Post.
I can hear it and am looking at my 60th birthday in a few months -- How old do you have to be to NOT hear it?
I do remember not hearing the "silent" alarm when I taught middle school. The kids all covered their ears in pain as I merrily taught on, assuming they were engaging in an act of collective subterfuge.
nice. it's like a test to see if your hearing is shot or not! i still got it baby!
aged 53 heard absolutely nothing