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Ultrasonic investigations in shopping centres

windytan.com

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Re: Ultrasonic investigations in shopping centres

#71

Post by metabagel »

skmurphy wrote: post #46
raverbashing wrote: post #45

Earlier quoted context omitted.

I'm not sure I ever managed to hear a 19kHz tone, but I'd say it might have been possible (or the tone was a lower frequency one). But yes the old CRT whine I could definitely hear

I was young. My mother could not hear it and thought I was just being annoying. This is several decades ago, now I can barely hear my turn signal blinker and am preparing to emulate my father's practice of driving a few miles with his blinker on after signalling a lane change.

One thing that can help is pressing the turn signal lever with less force than is needed to latch it. This should cause the indicator to flash three times and then stop. It’s an operating mode I wasn’t aware of for decades.

Re: Ultrasonic investigations in shopping centres

#72

Post by Nition »

ryandrake wrote: post #40
spondylosaurus wrote: post #5

Have you ever listened to a badly mixed song with a persistent high-pitched whine undercutting part (or all) of it? Certainly that's not on purpose either, but I doubt anystudio equipment is giving off an intentional "test" whine either, so I've always wondered how that ends up happening.

Whenever my daughter puts on recent pop music, I can tell instantly. Every pop song singer seems to have their voices artificially boosted into one or two higher harmonics. It's hard to describe in words but instead of the singer singing a single note, it's as if she (and it's very evident with female singers) has some very, very high pitched harmony automatically added, which lasts the whole song. It's not like a si…

The other comment is right that autotune is almost always present in recent pop vocals - even when the singer is excellent, a little bit is now commonly added to give it that certain sound.

Having said that, I think what you might be hearing is actually another modern trend - which is just boosting the high frequencies in the vocal a lot. Pop vocals right now are mixed very 'bright', sometimes almost painfully so.

Also common to actually have multiple vocal tracks. Sometimes just a double singing the same thing, but sometimes it can be pitched up or down an octave, and I've also seen "whisper" tracks where a whispered vocal is layered with the main one to give it even more of that bright breathy sound.

Re: Ultrasonic investigations in shopping centres

#73

Post by s1mon »

I searched the article for "occupancy" and nothing. These ultrasonic tones are most likely ultrasonic occupancy sensors used for lighting and/or security. Typically they're 25kHz or 40 kHz (i.e. out of normal human hearing range), but it's possible that they are measuring some subharmonics of the sensors. I've certainly encountered ones that have mechanical issues and will spit out frequencies that I can hear too well.

Re: Ultrasonic investigations in shopping centres

#74

Post by xphilter »

pavel_lishin wrote: post #20
hehdhdjehehegwv wrote: post #11

It’s been used for ads for years.

How so?

I brought some class actions years ago alleging the unlawful use of this tech for essentially ads purposes: https://topclassactions.com/lawsuit-settlements/lawsuit-news...

and https://www.freeadvice.com/legal/lisnr-responds-to-lawsuit-t...

Re: Ultrasonic investigations in shopping centres

#75

Post by alamortsubite »

leviathant wrote: post #37
spondylosaurus wrote: post #5

Have you ever listened to a badly mixed song with a persistent high-pitched whine undercutting part (or all) of it? Certainly that's not on purpose either, but I doubt anystudio equipment is giving off an intentional "test" whine either, so I've always wondered how that ends up happening.

Sometimes it's old ears, sometimes it's the people in the room being oblivious to it from hearing it too much. I tell the story a lot about kind of the inverse of this - I was mixing my band's (terrible) recording, and during a weekend of mixing, I heard the squeak from my cheap kick pedal, like an icepick to the brain, piercing through the mix. I did my darnedest to EQ it out, and felt pretty good about it in the en…

Thanks for not telling us the track! I probably love that song, whichever it is, and wish to remain ignorant.

Re: Ultrasonic investigations in shopping centres

#80

Post by antod »

Nition wrote: post #63
gocartStatue wrote: post #53

Earlier quoted context omitted.

Wait, people regularly just don’t hear it?

You'll usually stop hearing the CRT whine in your 20s, 30s if you're lucky. It's at nearly 16KHz and the highest frequency you can hear always drops as you age. Of course, these days people also regularly don't hear it since CRTs are nearly all gone.

Even back in my youth and early adulthood, there was a wide variation on how loud CRTs were between models and individual units. There were some that were close to silent for me, while others were very noticeable.
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