Have you heard 'the hum'? Mystery of Earth's low droning noise solved? | Hacker News Reader

Have you heard 'the hum'? Mystery of Earth's low droning noise solved?

independent.co.uk

84 pointschippy38 comments

I have heard 'the hum'. In my house in western Connecticut, at night when nothing else is on, everything is quiet. I'm far from the ocean. There is no industry near by. No trucks. Nothing. There is a hum... maybe about 40 - 70Hz. It's creepy the first time you hear it. It seemed to be coming from the ground, and the walls. I moved to the bedroom it was there too. It's very quiet. You can't hear it if anything else is on.

If you say this to people they think you are crazy. I've had my ears checked for other reasons and they are fine. I'm not on any medications, or anything like that. The hum is not ocean wave vibration forces. The hum is constant and consistent. It sounds of mechanical precision. I have little doubt the sound is from a man made object.

From Wikipedia: "The Hum" History

There has been little mainstream attention. Only a handful of articles have been published in scientific literature, including: Leventhall, 2004,[15] 2003;[8] Cowan, 2003;[16] Mullins & Kelly, 1998, 1995;[4] Broner, 1978;[17] Vasudevan & Gordon, 1977.[18] Others publications include: Frosch, 2013,[19] Deming, 2004;[20] Fox, 1989;[21] Wilson, 1979;[5] Hanlon, 1973.[22]

The Hum has been repo rted worldwide.[12] The World Hum Database and Mapping Project was launched in December 2012, in order to build detailed mappings of hum locations and to provide a database of Hum-related data for professional and independent researchers.[23]

http://en.wikipedia.org/wiki/The_Hum

> There is a hum... maybe about 40 - 70Hz.

I've always assumed it was coming from the power grid – it's the same frequency range, and gods know what metallic stuff in the walls could vibrate in resonance to it.

I hear the hum as well sometimes, in different locations (my home office, separate from the house - here I can hear it during the day) or in the house, at night. When heard, if I move my head a little bit, the sounds goes away and usually comes back a second later. I thought this was a nearby engine/motor (there are a lot of houses with installed heat pumps in the neighborhood), but as I've read the Wikipedia article, my money is now on tinnitus.

I've been running a FFY analyzer when I hear it and it's never been able to pick anything up actually airborne, nor any vibration through anything solid that would be picked up by a microphone.

But it doesn't explain why I can't hear it in just as quite places in different locations. If it was tinnitus wouldn't I here it in other places as well?

Any decent size transformer (or AC motor) in or near your house would hum at 60Hz (plus a bunch of harmonics). The big one on that utility pole down the street seems like a perfect candidate.

The problem I have with "the hum" is that it is framed as if there is one hum, where I see no reason to presume there couldn't be thousands of different causes for thousands of different low frequency hums.

The only constant I would expect to find is that some people are more sensitive to low-frequency noises than others.

It's not clear from the article, and I'm curious as to why it took them so long to figure out? Seismographs (which, as I understand, are able to "hear" the hum as well) are not a new technology.

The newspaper article (not the journal one) got essentially everything wrong...the journal article does not talk about this hum people claim to hear at all.

The paper describes a model for seismic noise generated at periods between 3 and 300 seconds (not Hz!) and I strongly doubt any human can hear that (frequency AND amplitude wise).

Seismometers did indeed record the noise for quite a while but it was mostly considered an annoyance. Now in the last decade or so we learned that we can extract useful information from the noise and this caused all kinds of new studies, some (like this one here) focused on determining the regions and mechanisms of the origin of the noise in the seismic wavefield.

There was a house I lived in at the edge of town, and late at night on the balcony (midnight, 1 am, etc) when it was very quiet I could hear really quiet booming sounds. It was quiet enough that if a car drove by on the nearest road it would drown out the sound. It was not a steady hum—more like a distant explosion or bass drum. It was frequent but not regular enough to be music. I would guess it was the 20 to 30hz range. I could never quite figure out what it was.

During a cross country bicycle trip my partner and I were camping just outside a tiny town in the middle of Colorado. I had trouble sleeping and kept getting out of the tent to look around due to what sounded like a large flag blowing in the wind, or a rabbit thumping its foot against the ground. Low, faint, slightly irregular. But there was nothing around. Lasted all night and morning. It was driving me nuts!

Exact same story here. I wonder if it was this.

Maybe something like this? https://en.wikipedia.org/wiki/Acoustic_shadow#Long_distance_...

Does someone know it's usual frequency? When it's quiet in my house there's a hum at around 50hz, but its very constant - no 13 to 300 seconds, it's always there. I first assumed it was someone in the neighborhood running a motor, or maybe the water plant a couple miles away, but when it was particularly noticeable during a widespread blackout here (in part, due to the quiet - and eliminating the likelihood of an electric power effect), my next ideas were a resonance from traffic on the interstate a couple miles away, or maybe someone even further doing some drilling (there's been discussion of fracking starting soon a dozen miles away or so, but it's not supposed to be happening yet, and I first noticed several years ago).

50 Hz is very characteristic for a power line close by but as you already ruled that out I have no clue. Nonetheless much to high for any seismic noise.

He's in the US, which rules out 50Hz at any precision. He needs to take measurements.

On the other hand, without measurements, 60 Hz may be close enough to 50 Hz to include it in "around 50 Hz", depending on the OP's ability to estimate sound frequencies.

But yes, measurements are the way to go.

On a piano, it's closest to the C three octaves below middle C, so around 33Hz. I regret my lack of perfect pitch.

Keep in mind the black out wouldn't rule out any electric device that had batteries or capacitors as part of it. I had a smoke detector that made a slight humming, took me forever to figure out where it was coming from, and replace that smoke detector.

Battery-powered smoke detectors will likely be running on DC so coil hum seems unlikely.

Unless it has a switching converter or regulator. Even when running at high frequencies they'll often generate harmonics in the audible range. It can take a heck of a lot of effort to keep a circuit quiet and nonmicrophonic.

Such as land line phones which still have power even in a blackout it's separate from power lines.

The phone line power must be AC I can't see such long runs being DC.

Actually, it's 48 volts DC (http://en.wikibooks.org/wiki/Communication_Systems/Telephone...). A few years ago I got to tour a central office for a small telephone/cable company in a suburb of Houston and the phone lines were actually powered directly by massive banks of lead-acid batteries which were then constantly kept floating by the mains supply.

Also there is radio waves interacting with passive objects.

I have been working with radio for the last few years and while my theory isn't that strong a colleague of mine was pretty clear that AM signals from planes (or control towers) had been observed to make detectable sound levels in nearby houses.

Not sure how it would work during a blackout, but it sounds like you're listening to a mains hum. http://en.wikipedia.org/wiki/Mains_hum

Depending on the blackout cause there could still be live powerlines nearby. If a local transformer blew then the lines feeding it would likely still be live until they shut them off to replace the transformer.

I hear that too, mainly at night, a constant droning that seems to come from very far away outside and from no specific direction, but bothersome enough to keep me awake.

I've been hearing it, at varying volumes from time to time. I also describe it as someone leaving a car running a few houses way. Going outside with the sound of the wind, and faraway cars makes it harder to detect. Once I walked a miles radius at 5am in the summer trying to find where it is from.

I assumed it was an all night nightclub. The hum was beat like, like the bass line from some fast dance music. But I've also heard it during the afternoon at home. Sometimes I thought I could hear higher pitched drum beat instead of a hum. I've heard this in two locations. Usually indoors is where it seems the loudest. I like the idea about sea waves, but I think it could be more mechanical in nature. Perhaps radio waves interacting with quartz crystals in bricks, cement or (around here) limestone blocks.

Note, I think this "hum" could be different or the same as the Hummadruz which has been recorded for centuries and is like bees humming. See http://www.northernearth.co.uk/permhum.htm for some more info.

"In 1878 R.E.Bibby, a local musician and composer, recalled from his 1820s childhood a low drone or humming noise heard in suburbs to the south and east of Manchester, especially Gorton, Rusholme and Longsight. It was heard on calm, clear days, usually in the early morning or at dusk. "

Quote that explains their finding:

"Researchers claim that microseismic activity from long ocean waves impacting the sea bed is what makes our planet vibrate and produces the droning sound.

The pressure of the waves on the seafloor generates seismic waves that cause the Earth to oscillate. [...]

The continuous waves produce sounds lasting from 13 to 300 seconds. They can be heard by a relatively small proportion of people – who are sensitive to the hums – and also by seismic instruments."

I'm pretty sure this is what it's always been thought to have been, assuming it exists?

This was the theory from forever ago.

Unless it's been conclusively proven or the wave type is different.

More newspaper science I guess.

My main takeaway from this is that when there's very strange unexplainable sounds on the Earth, the most likely culprit may be the Earth itself. Also see: https://en.wikipedia.org/wiki/Bloop

Nope. There is no evidence that people are actually hearing the hum described in the paper. In fact it's highly unlikely. Is there any evidence at all that the human ear can detect 0.1Hz?

I don't think it would come in thru your ear. Maybe resonating inside your body cavity?

I probably just don't know enough about acoustics, but could vibrations with a subsonic period travelling through the earth cause resonations in smaller air-filled cavities (e.g. underground air pockets/caves; the insides of buildings; bodies of water) that would then result in audible vibrations?

Yes, there have been instances of subsonic standing waves/resonance in hallways that have caused feelings of fear and reports of "ghost" sightings.

That's really just speculation, and it wouldn't likely sound like a "hum". Tinnitus and/or mains hum seems a much more likely explanation.

This hum terrorized me for months in Kirkland, WA. I falsely accused my neighbors over it -- they were completely innocent. Ended up moving a few miles away and haven't heard it since.

It's no fair, I have none of "the hum" here so I have to play my own drone on my speakers and I'm running out of bands.

Either way I'm pretty sure the entire phenomenon is just SunnO))) recording albums.

Actually it's probably Fraa Jad or some other Millenarian signing.

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