Infrasound source

[LRJ]

What could be producing this infrasound in my home? (see image - 2 & 4 Hz around 75dB, 7 & 9 Hz about 60dB)

It's a residential neighborhood and there are no industrial or commercial buildings for miles. Location is KC suburbs – no windmills nearby. HVAC not running while this was recorded.

[CaptDon]

How did you record that, with what type of input device? So you are going to have to be a detective here. First, is it centralized to your home or does it effect your neighbors also? It is probably being coupled through the ground. Are there any rock quarries within 5 miles 'that you know of? I know of some mines in central Pennsylvania that include underground tunnels underneath residential neighborhoods!!! You may own your property (until you fail to pay the taxes) but you may not own the mineral rights to the earth under your home!! My parents found that out the hard way!!!

[LRJ]

With a professional grade mic (iTestMic2 - Studio Six Digital product).
I checked with neighbors who are communicative when this began and no one was noticing anything.
No rock quarries that I'm aware of within that range.

Curious about "coupling through the ground". Is this something a problematic neighbor could pull off with the right equipment? One questionable neighbor's sump pump has been running when there has been no precipitation, for example. We can see this because their drain comes out between our two driveways and water being ejected intermittently on a fairly regular basis in recent weeks even when it's dry as a bone.

[moffy]

The mic has a quoted frequency range of 20Hz-20kHz  +/- 3dB, I am not sure what your are measuring but that is in the vibration level, transmitted by mechanical coupling not through the air, perhaps a seismic sensor would be better?

[Alex Eisenhut]

A train, or elephant, crossing.

[LRJ]

Not a train or elephant.

The disturbance has been ongoing and isn't just occurring for a brief period as one would expect with a vehicle, train, or anything similar. We also do not live near a highway or train tracks.

[Gyro]

Wind vortices, air vents etc.?

[CaptDon]

Gyro may be on to something, roof mounted sewer vents can resonate at low frequencies when the wind blows. Same effect like using a bottle for a whistle. Your frequency of interest is so low, most machines have a higher mechanical resonance or very low like 1/2Hz or periods extending into seconds. Do any of your neighbors have a rock tumbler or involved in tumbling steel scuba tanks? Frequencies in the range you describe are close to the natural resonance of a home and become magnified within the home but are undetectable outdoors. Do you have any urbanite neighbors who play rap music at the threshold of pain? They love the bass and the beat never changes for 10 minutes at a time (or more). The rap dimwits play the bass at about 20Db hotter than it was recorded and it couples through the air and ground. I have an inconsiderate neighbor about 5 houses away and I can hear their bass in my house, yet I hear nothing when I go outside unless I stand outside their house.

[coppercone2]

are you sure its not the amplifier. they have 1/f noise. usually measured to 10Hz. I don't see why a commercial product focused in the 20+ Hz range would care to give good performance at 2Hz, 10x lower then the absolute minimum spec (meaning they probobly only care as low as 40Hz).

[Alex Eisenhut]

We had construction nearby here in the metro tunnels, and it would create these tearing-metal sounds and floor movements that seemed to be coming from inside the house.
Also dishwashers. Upstairs got a new dishwasher and the sound from upstairs changed instantly, the woosh-woosh of the spray arm and the vibration of the pump was a pretty low frequency and focused over the kitchen. Like, not loud, but it's noticeable.
Next door is excavating and pile-driving, that's not fun.
Basically if you live in a city it's endless sources of noise. Ever see Dr Discord and Dynne from the Phantom Tollbooth?
https://youtu.be/vvDCnxYIalM
I thought it was fiction when I was a kid...

[coppercone2]

dynamite and demolition charges sound like someone is moving furniture on the floor above or below you (dragging heavy bed and its skipping on like a semi sticky vinyl floor) when far away.

I was certain someone was moving those fucking 1000lb lab tables around some where in the building with like 4 people. Eventually I asked WTF. Like did they hire a fucking interior decorator?. When I checked my email it turns out the construction company was blasting rock a little while away. I heard the same noise too, years before, near a facility that happened to have a seismograph outside their extra high security area.

[sharow]

You can do this.
https://www.youtube.com/watch?v=y7g6dKncO-I?&t=16
Or, if you provide raw sound file(8ksps/MONO is good enough), someone do this for you.

At least you can guess man-made or not.

[Terry Bites]

You may have two higher frequencies beating together.

[S. Petrukhin]

The earth groans from what is happening on it...