Ultrasonic investigations in shopping centres
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Ultrasonic investigations in shopping centres
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Re: Ultrasonic investigations in shopping centres
#2I live in Japan, Tokyo, and sometimes I come across these annoying/distracting high-pitched noises even in residential areas. They are a nuisance for bypassers too, if you've got ears young enough. But the residential areas don't have any problem with loitering youngsters, so I keep wondering if the noise is targeted against pests or wild animals. This article made me think if I should seriously start measuring the volumes and frequencies objectively. What kind of equipment would you need to get some data to get started with?
Re: Ultrasonic investigations in shopping centres
#3I live in Japan, Tokyo, and sometimes I come across these annoying/distracting high-pitched noises even in residential areas. They are a nuisance for bypassers too, if you've got ears young enough. But the residential areas don't have any problem with loitering youngsters, so I keep wondering if the noise is targeted against pests or wild animals. This article made me think if I should seriously start measuring the v…
> what kind of equipment
Any microphone hooked up to a laptop with a microphone input. Or a phone running some audio spectrogram app.
Getting started is very easy, but then you'll be constantly tempted by better sensors, more sensors, more channels, more analysis...
Re: Ultrasonic investigations in shopping centres
#4I live in Japan, Tokyo, and sometimes I come across these annoying/distracting high-pitched noises even in residential areas. They are a nuisance for bypassers too, if you've got ears young enough. But the residential areas don't have any problem with loitering youngsters, so I keep wondering if the noise is targeted against pests or wild animals. This article made me think if I should seriously start measuring the v…
I came across some of these in Tokyo recently as well. Super annoying, and I'm 40. I thought I'd be immune by now. I assumed they were intended to drive away cats or rats or mosquitos.
Re: Ultrasonic investigations in shopping centres
#5Have 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.
Re: Ultrasonic investigations in shopping centres
#6I live in Japan, Tokyo, and sometimes I come across these annoying/distracting high-pitched noises even in residential areas. They are a nuisance for bypassers too, if you've got ears young enough. But the residential areas don't have any problem with loitering youngsters, so I keep wondering if the noise is targeted against pests or wild animals. This article made me think if I should seriously start measuring the v…
> what kind of equipment Any microphone hooked up to a laptop with a microphone input. Or a phone running some audio spectrogram app. Getting started is very easy, but then you'll be constantly tempted by better sensors, more sensors, more channels, more analysis...
And you might accidentally get into field recording and manipulating sound with a portable modular synth... Oops
Re: Ultrasonic investigations in shopping centres
#7No mention of how bad this must be for dogs and other animals that can hear better than humans.
Re: Ultrasonic investigations in shopping centres
#8No mention of how bad this must be for dogs and other animals that can hear better than humans.
I always wondered the same about ultrasonic parking/proximity sensors on cars.
Re: Ultrasonic investigations in shopping centres
#9I live in Japan, Tokyo, and sometimes I come across these annoying/distracting high-pitched noises even in residential areas. They are a nuisance for bypassers too, if you've got ears young enough. But the residential areas don't have any problem with loitering youngsters, so I keep wondering if the noise is targeted against pests or wild animals. This article made me think if I should seriously start measuring the v…
> what kind of equipment Any microphone hooked up to a laptop with a microphone input. Or a phone running some audio spectrogram app. Getting started is very easy, but then you'll be constantly tempted by better sensors, more sensors, more channels, more analysis...
Normal computer recording only goes up to 48kHz (24kHz Nyquist rate, with analog filters lower than that to prevent aliasing) but high-quality equipment might support 96kHz or even 192kHz.
Re: Ultrasonic investigations in shopping centres
#10Have 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.
I've got an example of this: Some Blackpink songs (cannot remember which ones, possibly Playing With Fire or DDU-DDU-DDU) were mastered and released on Spotify/iTunes [unsure if has been removed now] with a 18-19kHz carrier tone (iirc it was actually a number of tones) modulated. The signal was very loud. I first noticed this in a friend's car and assumed it was because the song was ripped from YouTube, but later realized that all of the versions have this.
The reason for this is because at concerts, you can buy a piece of merch called a lightstick. Essentially, it is a STM32 and a mems microphone that is demodulating the carrier signal, so it can flash in time with the music. The tone has to be I assume the theory goes that anyone who has been to enough concerts to have a lightstick is no longer capable of hearing the noise.