131–140 of 304 posts
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On the YouTube video it definitely does sound like something strong going on underground... but that's probably a very poor method of assessment.
The audio on the video was probably added in post...
A few years ago they drilled for gas a few kilometers outside the city (about 3 km from my house) — this caused a faint humming noise that seemed to come from everywhere but nowhere in particular. Stand still in a room, hear the noise. Lie down, cover your ears, hear the noise. Put earplugs in, hear the noise. Hugely annoying if you're the kind of person that doesn't sleep well with such nuisances. Boy was I happy wh…
How does one eliminate the noise? One of those sensory deprivation chambers? Audio insulation?
As one who can hear these sounds, I can attest to how maddening it is. It's even worse when (most of) the people around you can't hear it, and they don't believe you. Earplugs only make it worse, because they filter out ambient noise that otherwise helps distract you from the incessant hum. Daytime is not as bad as night because of the natural activity sounds of a city. I have read that waves and underwater currents…
Next step would probably to get a few of these, see if you can record the hum on a few of them, and then start experimenting.
The theory behind triangulation is simple. But in practice, it's probably really hard to make sure all microphones have the same sensitivity. The standard approach depends on sounds being quieter when they are far away, but if one mic is naturally quieter (deeper inside the house, or more absorbant material, or just more obstacles in the way) that no longer works.
The best approach would be using a phase difference to measure. Exploiting the delay due to the speed of sound. That means you need some way to synchronize the recordings. Presuming a 20hz signal, you'd need your synchronization to be better than 0.05 seconds. This also requires the hum waveform to be easy to match. That is, you'd need to be able to tell the phase offset by matching parts of the sound.
You could also try a 'big data' approach, just cataloging all reported cases and looking for patterns. That requires dealing with very noisy data though, as reported cases will be inconsistent. This is due to people not always being home, not everyone hearing it, and no verification of reports.
edit: Interesing idea: use the 'bit data' approach together with wind speed and direction. The sound should be easier to hear when the wind blows it towards you. With enough data and corresponding wind data, you might have something. Does require compensating for correlation between time of day and the wind. If wind is west in the night, and less people hear things when the wind is west, that might just be because they are sleeping.
Some acoustic expert and hospitality expert should team up to create a hotel and/or spa that can dampen or eliminate the hum in some significant way in order to provide an oasis of relief for those severely affected... either through inverse cancellation waves (as suggested in a comment) or by air/water buffers around the property.
I'm listening to this right now [1] and (for those of you who don't have a chance to hear it right now) it definitely isn't what I would call a "hum"... that's way too gentle and not bass enough to describe this sound. I'd call it more like low-frequency rumbling (though that's probably not a perfect word for it either). [1] https://www.youtube.com/watch?v=tPDILKQjJW8
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"Since reports of it surfaced in 2011, the hum has been studied by the Canadian government, the University of Western Ontario and the University of Windsor." Do you really think that between the Canadian government and two universities, over the past seven years, that you are the first person to suggest this "obvious first step"?
I went to school and worked for a while studying spectrum management. It boggles my mind to this day that drones get in the way of fire fighting and emergency services because an obvious first step world be to allow emergency vehicles & helicopters to jam the frequencies of drones. There are plenty of other vehicles with this ability (military, secret service, etc) so it's not like the technology to solve the problem…
Sigh. I've coded too much this week. My brain just immediately went to: comment out half the city at a time and binary search the source. Guess you can't really do that. I wonder if the hum persists during a power outage.
A few samples of amplitude should be able to triangulate it no?
Consider:
* The amount of walls between a mic and the outside.
* The absorbance/reflection of nearby materials, including their shape (flat surface will reflect sounds amplifying certain directions).
* The clutter between the source and receiver. Sound carries over water, not over cities or forests.
* Similarly, elevation of the receiver. Higher means less effect of clutter, and obviously, a hill in between will be an issue.
* Wind direction. Wind will blow the sound away.
It might still work with enough measurements with the same microphone, but that is not a given. A decent backup plan would be measuring the phase difference. This is still frustrated by wind, but doesn't depend on the senstivity of the microphones. It does require synchronization of the recordings, which might also be difficult.
As one who can hear these sounds, I can attest to how maddening it is. It's even worse when (most of) the people around you can't hear it, and they don't believe you. Earplugs only make it worse, because they filter out ambient noise that otherwise helps distract you from the incessant hum. Daytime is not as bad as night because of the natural activity sounds of a city. I have read that waves and underwater currents…
https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_vortex_street
This has been cited as a possible explanation for strange noises in the mountains at various locations and also as a possible cause of the infamous Dyatlov Pass incident.
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... fascinating. There's no way that's easier than replacing the battery or even the detector itself. Why suffer through something so trivially fixable?
> Why suffer through something so trivially fixable? Because, in all likelyhood, they're not suffering at all. People vary greatly in what causes them discomfort. I imagine the population that doesn't attend to chirping smoke detectors has a strong selection bias for not suffering due to it. I don't mind carrying reasonably heavy things for miles on foot. I remember one weekend where I had some time to spare and need…