[orls]

That sounds more like coil whine, which is “normal” sound (i.e. moving air) from components vibrating rapidly. That’s not what this paper covers (= more like people’s brains “imagining” sound due to RF triggers)

The reason you remember adults not hearing it is because there is a well-documented loss of high-frequency hearing as people age.

(Which has even been “weaponised” before; there were stories some years ago about stores blasting high-frequency noise outside to deter loitering teenagers without affecting desirable adult shoppers)

[alex3305]

> Which has even been “weaponised” before; there were stories some years ago about stores blasting high-frequency noise outside to deter loitering teenagers without affecting desirable adult shopper

Yeah, they should only work for teenagers. Except for when you are visually impaired like me. I'm almost 35 now and still hear those high frequency noise. It is extremely annoying and even borderline painful. Last year I even got the cops involved when a parked car in front of my apartment constantly emitted a high frequency noise for deterring stone marten and I didn't know who the car belonged to. It was a pretty funny interaction in the end because none of the parties involved (except for me) could even hear the noise. But the car owner admitted they had such a device installed. Resulting in them just moving their car.

[NoMoreNicksLeft]

I've heard these sounds all my life, as recently as a few years ago. I'll be 50 next year.

[JohnFen]

The ability to perceive high frequency sounds decreases statistically with age -- but that certainly doesn't mean that all people lose the ability to hear them when they're older (and it also doesn't mean that all people can hear them when they're younger).

It's a distribution. Probably a normal distribution, but I don't know that for certain.