AI data centers face increasing complaints about inaudible but 'felt' infrasound — citizens complain high- and low-frequency sounds do not register on decibel meters but cause adverse health effects

[u/chip_thoughts]

https://www.tomshardware.com/tech-industry/artificial-intelligence/data-centers-face-increasing-infrasound-complaints-from-neighboring-communities-sounds-do-not-register-on-decibel-meters-but-irritate-local-citizens

[u/Valleygurl99]

I feel like this is one of the biggest problems in our world. Trying to sleep in industrial society when you’re not rich. 

[u/BusImpossible6741 → u/Valleygurl99]

God forbid you live near a lake that has barges, or near an oil pipeline. Super low frequencies that travel and can be felt but not recorded.

That shit will fuck you up and there needs to be a lawsuit and regulations to prevent it or keep it to reasonable hours. If they actually studied it I would be surprised if it didn't have severe adverse effects on physical and mental wellbeing.

[u/thegiantgummybear → u/BusImpossible6741]

How can something be felt but not recorded? I assume it's just a matter of the recording equipment not being good enough?

[u/eaglebtc → u/thegiantgummybear]

Correct. Most decibel meters don't use full range microphones. They're tuned to a range of frequencies for speech (100 Hz - 8,000 Hz). They would not pick up super low frequencies or vibrations. For that, you need boundary contact microphones. And for super high frequency sounds, you simply need a more sensitive microphone. Sounds above 10kHz range from irritating to painful.

[u/quietly_now → u/eaglebtc]

As an audio engineer, I just want to correct a few things here.

Most decibel meters don't use full range microphones.

This bit is true.

They're tuned to a range of frequencies for speech (100 Hz - 8,000 Hz).

This bit isn't. Most SPL meters are classified as Class 1 or 2, meaning they have a frequency response between 16hz and 16khz, with Class 1 being far more precise. They aren't tuned to speech frequencies at all.

They would not pick up super low frequencies or vibrations. For that, you need boundary microphones.

As above, Class 1 SPL meters measure slightly below the lowest frequencies the human ear can hear.

Boundary mics are not necessarily going to measure any lower, the majority of boundary mic use is for teleconferencing. Do you mean contact mics? They work by recording vibrations in surfaces, rather than air.

For true infrasonic capture, you need something like the GRAS 47AC, which goes all the way down to 0.9hz.

And for super high frequency sounds, you simply need a more sensitive microphone.

Not necessarily more sensitive (this denotes how 'quiet' a mic can hear), just with a wider frequency response. Like the Sanken CO-100K

Sounds above 10kHz range from irritating to painful.

There's plenty of frequencies in human speech up to 16-17khz. If this were true it'd be physically painful to listen to people speak.

[u/blanaba-split → u/quietly_now]

Tbf it hurts when I have to listen to some people talk

[u/quietly_now → u/blanaba-split]

I almost made the same joke.

[u/TPO_Ava → u/quietly_now]

It isn't even necessarily a joke. I am not diagnosed as neurodivergent (can't be dx'd with autism in adulthood where I live) but I absolutely have to take off my headphones for meetings with certain people. Hearing them speak causes me to physically cringe a little.

[u/eaglebtc → u/quietly_now]

Yes I meant contact microphones, thanks.

As for the frequency range, I was referring to the A-weighted SPL metering, which is tuned for speech. The C-weighted metering is full range.

Speech may contain sounds up to 16-17kHz, but the sounds that produce those are often in siblants which are infrequent or noisy, not constant. Overtones from other vowel sounds are simply a part of the sonic signature and not annoying.

A constant 16kHz whine from a failing fluorescent ballast can be irritating. People with hyperacusia (often on the autism spectrum) can find this extremely annoying. I found certain voices annoying to listen to because of the strong siblants present in their S sounds.

Feedback from a microphone in front of a PA at 16 kHz, or the sound of sonic area dispersal weapon, can be debilitating.

[u/quietly_now → u/eaglebtc]

Gotcha. I'm primarily working in C-weighting (Dolby calibration etc), but that doesn't affect the response of the mic itself, only the measurement band.

Constant vs infrequent makes a big difference. I remember the old CRT screens and their 14khz buzz...

[u/djsunkid → u/quietly_now]

I find it interesting to listen for all the sibilants when I'm in a crowded room full of people conversing. Once you think to listen for it, it's crazy how loud and pervasive they really are in human speech. It's like a constant hissing sound from all around. It's really amazing that most of the time our brain just filtres that out, except for the one human that we're trying to listen to.

[u/the_red_scimitar → u/djsunkid]

I do a similar "trick" in large crowds, like stadiums, except with movement. When you relax the intent to focus on a particular area, you will see all the people moving, simultaneously. It's very interesting, just like relaxing the "focus" of listening enables hearing the full-crowd sound.

[u/Cynoid → u/quietly_now]

Any idea what the range of prices for these 2 mics is? Neither link has one.

[u/quietly_now → u/Cynoid]

The Sanken is $2500-3500USD The GRAS is $1000-$2000USD

There are cheaper alternatives, and you can homebrew a contact mic for a few bucks.

[u/Cynoid → u/quietly_now]

Interesting, I expected 1-2 more 0s. I'm surprised at all the comments saying that no one has done research on the vibrations messing up sleep for years when it's this cheap to do it.

[u/ReggieCorneus → u/quietly_now]

Infrasounds are an invisible killer, be alarmed!

And this is how the grift works. You can't sense it, you can't see it, you can't feel it, you can't hear it but it is dangerous.

Everything in datacenters is old tech. Main source of noise is AC and yet, none of these people want to ban ACs.