Presbycusis & The Mosquito Ring Tone

My son came up to me and said: “Hey Dad, listen to my new ring tone.” He opened his phone, pushed a button, and held it up for me to listen. I was expecting another piece of music, maybe something loud, or something with a pulsing rhythm. I waited. But there was nothing. “Isn’t that annoying?” he said. I shrugged, wondering when he was going to play it. But he had played it, he said. It was a ring tone that only teenagers can hear. I thought he was joking. He told me to listen and he played it again. “Don’t you hear the buzz?” he said. I shook my head. It’s called presbycusis. The “presby” suffix comes from the greek work for old. It appears that I have old ears. A clever brit named Howard Stapleton (winner of this year’s Ig Nobel peace prize) discovered that a simple sine wave at 17 khz is audible only to teenagers.

As we age, the range of audible sounds decreases. Stapleton used this fact to keep teenagers from loitering. For example, owners of convenience stores can blast this buzz continuously. The teenagers leave after a couple of minutes while the grownups do their shopping undisturbed. But teenagers have found an alternate application—they can text message one another during class without getting caught. What began as an obstacle has reinvented itself as an opportunity—with the help, no doubt, of some marketing savvy. Listen to the ring tone here.

I can’t hear it. Can you? As an experiment, I downloaded a tone generator to test just how much my hearing has deteriorated. I can hear up to 13454 Hz which, according to the chart, is not bad for someone my age. My wife can hear up to 12699 Hz which is a semi–tone lower than me. Given that she’s older than me, it only stands to reason that her hearing would be worse. (OK, so she’s only 6 weeks older than me.) Note, however, that this measures pitch—not volume. I still can’t get away with muttering nasty things under my breath, unless I mutter them in a high–pitched squeaky voice. I’ll have to wait another 20 or 30 years for that benefit of aging.

With this discovery, and the recent purchase of a pair of reading glasses, and the head shaving to hide the male pattern baldness, I’m beginning to detect the first hints of a midlife crisis coming on. If I’m not careful, I might find myself frequenting Porsche dealerships! Realistically, though, this is less an occasion for a midlife crisis than for an epistemological crisis. How do I know that I’m not missing things? Not just trivial blips of sound, but important things too, like screeching tires approaching from behind. And how do I know that my kids aren’t doing all sorts of things right under my nose? After all, I wouldn’t have known a thing about the mosquito ring tone if my son hadn’t told me about it. Then again, if he’s telling me about it, I doubt I have to worry.