Supersonic Ringtones

Well, not quite. It's pretty well-known, I suppose, that people generally lose the ability to hear higher frequencies as they get older. Seems like some grade-school kids are taking advantage of this. Kinda smart, I think. I can here the "mosquito" sound perfectly well, but I'm not sure if I can hear the 18kHz tone. Acutally yes, I can hear it, but not very well. If I jack the volume of my speakers most of the way up, I can hear it very well, but I'm not sure if that's just distortion caused by the amplification (then again, it's a hardware amplifier, so I'd think not). Probably the tone is very close to the edge of my audible range.

Kinda neat, and amusing.