Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

There's a Persistent Hum in Windsor, Ontario, and No One Knows Why

nytimes.com

Post reply on HN
Print view View original

171–180 of 304 posts

Re: There's a Persistent Hum in Windsor, Ontario, and No One Knows Why

#171

Post by vl »

eeZah7Ux wrote: post #154
kawfey wrote: post #70

Earlier quoted context omitted.

With laughable accuracy: http://fox61.com/2013/05/22/fox-ct-investigation-is-costly-g... Part of the problem is multipath due to reflections caused by buildings, hills, trees, etc. Anytime you listen to thunder or fireworks the rumble persists due to reflections off of such things. It's incredibly difficult to algorithmically remove multipath from terrestrial sources.

Correct. At 30 Hz directionality is a pipe dream.

It's relatively trivial to find direction of the 30 Hz sound source, given 1 million budget - you just need to place microphones 11 meters apart and raise them above buildings until you get direct line of sight to the main source.

Re: There's a Persistent Hum in Windsor, Ontario, and No One Knows Why

#172

Post by robertelder »

wl wrote: post #143
rocqua wrote: post #133

Earlier quoted context omitted.

Some googling yields this: http://earthworksaudio.com/microphones/m-series/m50/ which should be sensitive enough to pick it up. 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 de…

I wouldn't recommend the Earthworks M50 for this application. Earthworks' design approach for these microphones is to maximize time domain performance by having excessive bandwidth, minimal phase distortion, and flat frequency response. In order to achieve this, they have to use a tiny condenser element, which has relatively low sensitivity and thus relatively high noise. If you're looking to measure things near or b…

Since you seem fairly knowledgeable about this subject, perhaps you could answer a related question I've been wondering: Would an effective low-cost way of measuring low frequencies (let's say ~20hz) be to use a subwoofer speaker (used as a microphone) hooked up to something that would amplify and recording of the signal? My reasoning is that they're naturally designed to work with low frequencies to begin with (more so than a typical microphone anyway). I would also reason that you could also do a frequency response test over a range of known frequencies and power levels for the specific subwoofer to begin with, and then write a specific software filter to normalize whatever you record from it to get the 'true' sound. Does that make sense?

Edit: Also, note that I mean doing hardware amplification of the electrical signal in the wire coming directly from the motion of the magnet of the speaker.

Re: There's a Persistent Hum in Windsor, Ontario, and No One Knows Why

#173

Post by danans »

As a kid I remember going past the area around Zug Island on a boat.

I have a distinct memory of the huge stacks billowing yellow smoke, and the twists of ductwork forming structures that look like hellish versions of the buildings from a Dr Seuss story [1][2]. It was simultaneously amazing and terrifying, and I couldn't take my eyes off it until it passed out of view.

Years later I'd learn about how poorer neighborhoods were in the shadows of and downwind of such places.

I don't know if this place is uniquely terrible or this is the invariable cost of steel production. But I imagine this sort of thing is common in the industrializing world today, where a lot of steel is produced. Is there an example of a "better" way to make steel?

[1] https://www.flickr.com/photos/gsgeorge/3705474769

[2] http://rebelmetropolis.org/a-hellscape-among-the-ruins-zug-i...

Re: There's a Persistent Hum in Windsor, Ontario, and No One Knows Why

#174

Post by ClassyJacket »

vortico wrote: post #59

Garbage, sensationalist title with mentions of "unknown origin". Even the article says the likely source is Zug island, but of course this wouldn't get as many clicks. According to the mentioned University of Windsor report ( http://www.international.gc.ca/department-ministere/windsor_... ) "A previous study confirmed the existence of the low frequency excitation and estimated the source to be in the vicinity of Zug…

> If all of the above is impossible for whatever reason, why doesn't the article mention the reasons

I'd say you didn't read the article. They're pretty clear that it's because Zug Island is in the USA while the sound problem affects a city in Canada.

Re: There's a Persistent Hum in Windsor, Ontario, and No One Knows Why

#175

Post by dingo_bat »

throwaway613834 wrote: post #131
bowmessage wrote: post #127

Earlier quoted context omitted.

The audio on the video was probably added in post...

Could you elaborate on why that is necessarily a problem? Couldn't they have done it losslessly?

Because it could have been synthesized.

Re: There's a Persistent Hum in Windsor, Ontario, and No One Knows Why

#176

Post by monk_e_boy »

blunte wrote: post #101

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…

If I open the front window and back window in my car then drive at a specific speed I get a very weird woop-woop-woop and it feels like the air is pushing me back and forth in my seat. It pulses my head.

Wonder if it is something similar.

Re: There's a Persistent Hum in Windsor, Ontario, and No One Knows Why

#177

Post by monk_e_boy »

sneak wrote: post #129
bufferoverflow wrote: post #90

Earlier quoted context omitted.

Just install the debugging microphones all over, collect the data, find the source (if it's real).

Why install anything? Fly a drone around to take 5s recordings at points on a grid.

Wouldn't the sound of the drone be louder than the hum?

Re: There's a Persistent Hum in Windsor, Ontario, and No One Knows Why

#178

Post by nradov »

Cookiesaurusbex wrote: post #53
ocdtrekkie wrote: post #32

Earlier quoted context omitted.

"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…

Jamming equipment is heavy, bulky, expensive, maintenance intensive, and especially power hungry. Plus due to the vagaries of signal propagation the effects are somewhat unpredictable. Installing jammers on civilian helicopters would be totally impractical.

Re: There's a Persistent Hum in Windsor, Ontario, and No One Knows Why

#180

Post by davesque »

phlakaton wrote: post #169
blunte wrote: post #101

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…

I'm confused. The attached NY Times video clip has a very audible and noticeable hum and throb – it can't be just infrasound. Is that the actual hum people are hearing/not hearing? Or is it an attempt to reproduce it, perhaps?

Yeah. I also wondered about this.
Post reply on HN