111–120 of 145 posts
Totally speculative territory, but I’ve had headaches when going to a shopping center since I was a kid. It’s infallible, one to two hours and my head is exploding. I’ve always attributed it to the noise, crowds and sensory overload but it never happens elsewhere. Could it be?
Very interesting. I can remember being able to hear a high pitched tone when I was 4-6 shopping with my mother in department stores that seemed to get louder when we approached flush mounted speakers in the ceiling. This article measures the frequencies and explains it's a normally operating feature of the systems.
I dont know much about analog audio but if I am remembering correctly, the device could inject a 1Khz tone that was only heard on speakers with impedance problems.
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Or the idea that the humans are just blissfully unaware while their 'hyper' cat/dog is stuck inside a home with some device screaming 24/7, LED lights flashing, etc.
That’s … a horrible thought. How does one get a 19khz microphone to check I guess?
Edit: https://play.google.com/store/apps/details?id=org.intoorbit.... this is the app I use most. Phyphox (https://f-droid.org/en/packages/de.rwth_aachen.phyphox/) seems to only go until 6 kHz but has a lot of other tools. For those wanting to avoid GPlay, this F-Droid app seems to go slightly above 20 kHz but I don't like the interface as much as spectroid: https://f-droid.org/en/packages/org.woheller69.audio_analyze...
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The unfiltered pilot tone was a problem when recording FM radio onto tape, beating against the bias tone and confusing Dolby NR into thinking there was constant sound. High-end cassette decks had an "MPX Filter" which was a sharp 19kHz filter before the recording system.
You betcha! And FM broadcasts have a high-frequency pre-emphasis, which adds something like 10dB of boost to audio high frequencies. This is to reduce high frequency noise that occurs in analog FM systems. Radio receivers have a matching de-emphasis high-frequency cut. Indeed, both vinyl phonographs and audio tape systems employ similar pre-emphasis and de-emphasis. It's the RIAA curve for phonographs. Not sure what…
FM Radio transmitters broadcast a continuous 19 KHz pilot tone to indicate that it's a stereo broadcast. If it's present, then there's also a 38 KHz AM modulated carrier, which has the stereo information. The main FM modulation is (Left + Right) audio channels - the baseband. The 38 KHz subcarrier is (Left - Right). Notice that the stereo information is likely to be higher noise, being AM and without a lot of power.…
The unfiltered pilot tone was a problem when recording FM radio onto tape, beating against the bias tone and confusing Dolby NR into thinking there was constant sound. High-end cassette decks had an "MPX Filter" which was a sharp 19kHz filter before the recording system.
Accidental DRM even before the "D" came to be.
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I wonder how much of this sound pollution disproportionately affects autistic people. We need to make our soundscapes accessible.
Or the idea that the humans are just blissfully unaware while their 'hyper' cat/dog is stuck inside a home with some device screaming 24/7, LED lights flashing, etc.
I 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.
https://www.theguardian.com/uk/2007/mar/17/society.humanrigh...
Earlier quoted context omitted.
I wonder how much of this sound pollution disproportionately affects autistic people. We need to make our soundscapes accessible.
Or the idea that the humans are just blissfully unaware while their 'hyper' cat/dog is stuck inside a home with some device screaming 24/7, LED lights flashing, etc.
Earlier quoted context omitted.
Or the idea that the humans are just blissfully unaware while their 'hyper' cat/dog is stuck inside a home with some device screaming 24/7, LED lights flashing, etc.
My ex got a device to discourage ants. Then forgot where she placed them. Then found out that it was in my daughter's hearing range. Finding the last one was a nightmare. Here is the device. https://www.amazon.com/Ultrasonic-Repeller-Electronic-Repell... It was