I am always so surprised and appalled that these things are still legal. Can you imagine the reaction if they were designed to only hurt pretty much any other demographic other than young people?
It’s fundamentally an attack on public space and should be illegal. I’m sitting in a small public parkette right now within earshot of an establishment that has one of these things running 24/7. I don’t even know which one as I can’t locate the precise source of the sound. It emits a high pitched whining noise for about 5 seconds, at which point the frequency rapidly increases until it ends in a zap, followed by about 2 seconds of silence. This differential makes it impossible to ignore. It even permeates headphones. I like eating lunch here, as it’s close to my office and a nice space, but I often leave irrationally angry after being unable to relax in the midst of this omnipresent noise.
Sadly there doesn’t seem to be anything I can do about it.
They are easy to locate. The sound can't pass through your hand and doesn't diffract much, so move your hand around at arms length till you can't hear it anymore in one ear, and that's the direction it's in.
Normally they're metal boxes with a grille on the front mounted above head height (because otherwise some teen would put gum in the grille to stop the sound getting out)
I keep hearing similar high pitched sounds in Tokyo in front of some stores as well, so the statement that only people up to 25 years old can hear it sounds incorrect.
Ultrasonic jewelry cleaning baths, these sonic youth deterrents, and a few other super high pitched sounds give me instant splitting headaches and I'm 28. Strangely I have terrible hearing otherwise and have to ask people to repeat themselves a lot.
As part of the affected age group, it sounds a lot like the high-frequency sound of a CRT monitor / old arcade machine (that older people cannot hear apparently), which is very much not pleasing. I can't imagine having to deal with that all night long.
When I was younger, I thought for sure I had a sixth sense for detecting when the TV was on. Strangely, it didn't really seem like a sound to me. More like something inside your head.
Unfortunately, my super power didn't pan out to be all that unique ... or useful.
These have been around for quite some time. I remember encountering them in Japan about 13 years ago. It was in a fancy store in Tokyo, next to the Palace. As soon as I entered, my 30 year old ears alerted me that they hadn’t died off at 25 as planned. The one clerk in the store couldn’t turn it off and apologized profusely. I decided to have fun, and in my broken Japanese, accused her of having a device to ward off gaijin. She denied it profusely as I walked out, laughing... on to the next store.
Part of the reason they installed these devices is in part to reduce vandalism, but I can’t imagine any better motivation for vandalism than an extremely annoying sound coupled with moral justification provided by clear discrimination. They’re just asking for these devices to be destroyed.
I can understand the motivation, legality aside, but the implementation seems irresponsible to me.
A device like that will very likely annoy, if not anger, dogs at distance.
My old cats could hear two rooms away a 40 KHz signal played by a piezo transducer directly connected to a function generator with no amplification in between. An old ultrasound TV remote had the same effect. And cats hearing although better than ours is less sensitive than dogs'. I can't imagine what level of discomfort that device could put on cats, dogs, bats and other animals.
I seem to remember this effect being co-opted by teens to turn the tables. Use it as a text notification sound on your phone and you can text back and forth in class without alerting the teacher.
I'd settle for blasting something loud directly at people who came up with, approved, and implemented the idea. "but one that only teenagers and young adults can hear" is a lie of averages. High pitched sounds in my mid-30s are more annoying than any teenagers.
You joke but many of these sonic weapons in the UK have been replaced by speakers playing musak versions of opera. Bad classical music deters young people more effectively.
First they came for the mosquito... but I was not a mosquito... then they came for the rats... but then i was not a rat... then they came for the teens... but i was too old to be a teen...
Reminds me of how Zoom Rooms play ultrasound to automagically pair your computer to the room [1].
For a while I thought I was going crazy hearing this incredibly high-pitched, faint chirping in meeting rooms when no one else could (I have weirdly good high-frequency hearing). There's probably a solid limit to how far into inaudible ultrasound Zoom can push this sound, though, considering that computer microphones are designed to pick up things that people can hear.
I fully intend to break these devices if I ever hear them. I'm over the age of 30, and can hear them quite clearly; it violates my right to be in public spaces. Even if the device is installed in privately owned property, it's not like the sound waves magically stop at the end of that property. Regardless of the law, the use of these devices within hearing of public space is against the public good, and they should be destroyed if heard.
One of the joys of aging to me is being immune to these noises while still enjoying music to the fullest. When I was young it was often agony going into stores that had alarm systems employing these high-pitched hums. Neither of my girlfriend nor her family, with whom we spent a great deal of time, could hear them. They were patient but bemused at my reaction.
When I was a kid the local 7-Eleven installed outside lights that made your skin have a slight greenish hue and which made acne stand out. Great way to get rid of loitering teens without any harm.
