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

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

#171

Post by divbzero »

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…

> the main tone is at 440 Hz

The largest tuning fork in the world! [1]

[1]: https://en.wikipedia.org/wiki/A440_(pitch_standard)

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

#172

Post by peterkos »

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…

every musician ever: A440 PROVEN BY THE BRIDGE

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

#173

Post by gibsonf1 »

I rode across the bridge in high winds last week and I thought that the bridge might be failing somehow - the sound was almost unbearable - I thought a serious safety issue was potentially occurring because of a structural frequency effect. I guess the good news is that there is no emergency - bad news is maybe ear plugs on bike rides on windy days.

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

#174

Post by aportnoy »

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…

In Python, you can use sounddevice + scipy.fft + matplotlib to implement this functionality yourself.

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

#175

Post by Drdrdrq »

alias_neo wrote: post #165
Drdrdrq wrote: post #135

Earlier quoted context omitted.

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.

I forgot about the part where you would have a phone and can call for help! Why is the landing part hard, is it about maneuvering and slowing?

In the marinas you have limited maneuvering space and with sails you are limited in which directions you can go - directly against the wind is not possible, you need to zig-zag. Slowing is also a bit more difficult. To add to trouble, marines are often built in places with less wind (of course) and wind might change direction during landing. Note that it's still quite possible, just more challenging, risky too I guess, and also forbidden in many marines. But it's a good exercise, it makes one respect ancient mariners even more.

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

#176

Post by gpm »

Animats wrote: post #158
gpm wrote: post #150

Earlier quoted context omitted.

Sound travels, what, 30 centimeters a ms? Bluetooth/wifi is good for at least a few meters, and should have latency of around a ms. Should be pretty easy to synchronize via that.

You need to maintain millisecond sync while the devices are widely separated, possibly for hours. Cell phone clocks are not millisecond-accurate over hours. The idea is that a group of people all download the app and walk or drive around the area of interest collecting time-stamped audio and sending it to a server. Amusingly, data collection would be easier with analog technology. Get some VHS walkie-talkies, and, at…

For sounds transmitted through the air, ms precision is really necessary at distances of more than a few meters. Network time should be close enough at 10s or even 100 ms (roughly speaking I guess this is complicated by the fact that the speed of sound through the ground is ~6km/s. Rather faster than the speed of sound through the air. Multiplying those errors by 20... but 200 meters of error isn't that bad. A powerful local network with no latency would then be enough to isolate further.

Anyways, turns out that you can get gps time on androids, so this should be solvable with much better latency https://stackoverflow.com/questions/7017069/gps-time-in-andr...

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

#177

Post by konschubert »

narrator wrote: post #164

The second law of thermodynamics says that the energy of reducing the wind's speed has to go somewhere. It's either going to push the bridge around, make noise by generating vibration, generate electricity as in a wind turbine, or some combination of the three.

Well, I guess the goal may have been to let the wind pass through.

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

#178

Post by krisoft »

CamperBob2 wrote: post #151
01100011 wrote: post #80

Earlier quoted context omitted.

I was going insane at my old house because of 'the hum'. It started when I installed double pane windows. I think they dropped the ambient noise to the point where the hum was obvious. Any idea what you'd use to track down very low frequency noise sources(i.e. 15-60Hz)? I don't think a lot of sensors do well in that range.

Get an audio spectrum analyzer app for your phone, and enable its log-X scale. Very useful for this sort of thing. The FFT will reveal sounds you don't hear yourself.

They are indeed cool, but no math magic can help you if your microphone is not picking up the signal. I don’t have datasheets for mobile phone microphones but lets look at some professional ones. The Senheiser MD 46 goes down to 40hz. The Behringer MC8000 goes down to 15hz. These are just two random samples I looked at to illustrate that its not obvious that a microphone will even have a good response down to 10hz.

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

#179

Post by jedberg »

mdbauman wrote: post #82

I hope somebody has a chance to make high-quality samples/recordings before it's fixed. I doubt we'll get the chance to hear an instrument like this again, accidental or not.

> before it's fixed

Given that it was intentional, what makes you think it'll be "fixed"?

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

#180

Post by pengaru »

Maybe they should find a way to generate electricity from the bridge, it sees plenty of wind practically every single day for the same reason the SF bay is great for sailing.

https://patents.google.com/patent/US9444372B2/en

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

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