New slats make the Golden Gate Bridge sound like a David Lynch movie • Hacker News Board

Re: New slats make the Golden Gate Bridge sound like a David Lynch movie

#131

Post by zw123456 » Sat, Jun 06, 2020, 7:31 PM UTC

japhyr wrote: post #47

zw123456 wrote: post #18

Does anyone know if they are planning on removing the slats? Maybe if they randomly changed the spacing of the slats if it would alleviate the problem ?

What's resonating? If the slats themselves are resonating, spacing them differently won't help much. Then again, if it is the slats would a horizontal brace running along the middle of the slats dampen or eliminate the resonance? | | | ------------- | | |

Good point, it could be that they are vibrating like reeds. Bracing could help in that case. or could they attach weights to each one to change the resonant behavior ? It would be interesting to get a high speed video of one to see.

Re: New slats make the Golden Gate Bridge sound like a David Lynch movie

#132

Post by clairity » Sat, Jun 06, 2020, 7:34 PM UTC

systemvoltage wrote: post #12

metalliqaz wrote: post #10

Earlier quoted context omitted.

Every engineer, not just the ones building bridges. I was required to take an Engineering Ethics course that covered Tacoma Narrows as well as other incidents, such as the famous Hyatt Regency walkway.

I second that. As a mechanical engineer, we needed to learn about public works and prior disasters that has happened when there is lack of rigor or otherwise oversight, including Tacoma bridge and Hyatt Regency walkway.

i covered them twice even. once as a mechE undergrad, and again in business school. the former primarily focused on the engineering dynamics and ethics, and the latter primarily on the organizational behavior and decision-making failures.

Re: New slats make the Golden Gate Bridge sound like a David Lynch movie

#133

Post by johnghanks » Sat, Jun 06, 2020, 7:35 PM UTC

tobinfricke wrote: post #125

I tried making a spectrogram: https://twitter.com/nibot/status/1269347206445756416 I tried using baudline[1] (a 20-year-old program!) but it didn't work out-of-the-box on my current Linux installation. Instead I found something called Sonic Visualizer[2], which, while not real-time, worked out of the box. Using Pulse Audio 'pavucontrol' it was easy to configure Sonic Visualizer to use as its input the 'monitor' chann…

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Re: New slats make the Golden Gate Bridge sound like a David Lynch movie

#134

Post by empthought » Sat, Jun 06, 2020, 7:36 PM UTC

nyanpasu64 wrote: post #76

Balgair wrote: post #72

Another 'cool' mega-instrument is the Earth Harp. Instead of transverse waves (plucking) the strings, you use compression waves (pushing) in the strings to make the vibrations. Due to some physics here, you then need a very large resonator to hear the sounds. Essentially the Earth itself. Here's a good video from the Burn at an Earth Harp performance: https://www.youtube.com/watch?v=c66w_pPnO-s

How do they get audible sounds from strings hundreds of meters long? Massive tensions?

https://en.wikipedia.org/wiki/Overtone

Re: New slats make the Golden Gate Bridge sound like a David Lynch movie

#135

Post by Drdrdrq » Sat, Jun 06, 2020, 7:38 PM UTC

alias_neo wrote: post #90

forgotmyp77 wrote: post #67

Earlier quoted context omitted.

how did you get out of that one?

Use the sails and lift the anchor manually? (I'm guessing, don't have a yacht).

You would have trouble landing without the engine though. Better not to risk it if there's no problem with being anchored there, and just waiting for the fix.

Re: New slats make the Golden Gate Bridge sound like a David Lynch movie

#136

Post by stn8188 » Sat, Jun 06, 2020, 7:40 PM UTC

closeparen wrote: post #93

johnfn wrote: post #59

Earlier quoted context omitted.

Pretty interesting hypothesis! I don't think so, though. It was a fairly electronic sounding boop, almost like a low sine wave. A fog horn sound has more acoustic qualities to it. Also, if it was a fog horn, I don't know why it would only be audible in Nob Hill and no where else I've been in SF.

The Bay foghorns are electronic tones; they don’t sound like classic/cartoon foghorns at all.

If it's anything like the most common fog horn that the USCG uses across the country, it's a 273Hz tone (though I don't recall the waveform, most likely sinusoidal).

As of 8 years ago, they were using the FA-232 model fog horn, the circuitry was designed in the '70s and uses discrete BJTs on the boards to generate the tone and drive the "speaker".

Re: New slats make the Golden Gate Bridge sound like a David Lynch movie

#137

Post by jrockway » Sat, Jun 06, 2020, 7:41 PM UTC

hbarka wrote: post #25

Reminds me of Google’s old Crittenden Lane buildings. The buildings have exterior metal vertical slats over windows for shade control. They sing when it’s windy.

I never knew that. I am surprised there wasn't more chatter about how the sound attracted or repelled mountain lions.

Re: New slats make the Golden Gate Bridge sound like a David Lynch movie

#138

Post by yread » Sat, Jun 06, 2020, 7:50 PM UTC

Drdrdrq wrote: post #135

alias_neo wrote: post #90

Earlier quoted context omitted.

Use the sails and lift the anchor manually? (I'm guessing, don't have a yacht).

You would have trouble landing without the engine though. Better not to risk it if there's no problem with being anchored there, and just waiting for the fix.

It's possible - I did the RYA training which describes the theory of it and we even involuntarily attempted it in practicals (gearbox broke and it wouldn't go forward). But it's definitely not easy. In the end we hit a spot in the marina with absolutely no wind and had to swallow our seamanship pride and back up there

Re: New slats make the Golden Gate Bridge sound like a David Lynch movie

#139

Post by jonas21 » Sat, Jun 06, 2020, 7:51 PM UTC

Godel_unicode wrote: post #119

spike021 wrote: post #106

Earlier quoted context omitted.

When I visited Japan last year, I drove a mountain road one day with these guard rails/posts that were specifically made so that as cars pass by they emit a tone of a simplistic song (if I'm remembering correctly it was "Itsy Bitsy Spider"). Thought that was super interesting and a cool experience; a literally cool experience, since it was snowing and my friend told me so I made sure to have my windows completely ope…

Reminds me of the Honda commercial a few years back with the musical road: https://m.youtube.com/watch?v=YR5Cejq2uyc

Unfortunately, there was a miscalculation in the distance between grooves that meant the musical road didn't play the right notes:

http://davidsd.org/2008/12/honda-needs-a-tune-up/

Re: New slats make the Golden Gate Bridge sound like a David Lynch movie

#140

Post by pierrec » Sat, Jun 06, 2020, 7:55 PM UTC

_bxg1 wrote: post #28

I honestly think this is awesome and beautiful, though I might feel differently if I lived nearby just because of how relentless it is. I remember years ago I had the idea that if you could design construction equipment to rotate/oscillate/whatever at frequencies that were harmonic with each other, construction noise would become musical, almost like a very loud set of wind chimes.

There's a scene like that in the 2003 version of Zatoichi. But it's with manual construction equipment, so the musicality is rhythmic rather than harmonic.

https://www.youtube.com/watch?v=hk4oGCPGXz4