I want to see this graphed...
Eric Hertz wrote 04/23/2015 at 16:35 • 0 pointshttps://www.facebook.com/RYOT/videos/1050462568300707/
The third string down in the still-image, how it seems to spike, I propose the actual string is in fact vibrating sinusoidally and would appear as a sine-function if limited to the vertical-plane... but instead it's vibrating in two dimensions, one vertical in the image, and the other in the plane formed between the camera and the string itself.
Would those two sinusoids be of the same frequency, or is one harmonic shown on each axis...? in phase?
e.g. y=sin(t); x=cos(t) or...?
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Online 3D parametric-curve grapher...
http://www.math.uri.edu/~bkaskosz/flashmo/parcur/
not quite the curves I was expecting from merely x=sin(t), z=cos(t), y=t
I guess you're right about the multiple wavelengths, where it was plucked, etc...
And, I suppose, there's really no way to know exactly what (3D) waveform was playing...
The graph of x=cos(t), y=t, z=sin(t/2) looks a bit like I was envisioning when rotated.
So the "plane" I was envisioning between the camera and the string would be along the bottom "plane" of the graph above (viewed on edge).
Anyhow, my (plausibly horrendously-under-informed) thought-process was something along the lines of: a string as tight as a guitar's probably wouldn't resonate with such apparent "spikes" and "flats" for very long, thus maybe they could be explained via simple sinusoids and viewing-angle.
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hooray for the internet, I love how you can do almost anything online now :)
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if you know what you're looking for... and then know how to word it in such a way that Google will know what you're looking for... and then know how to word it in such a way that Google won't assume that you made a mistake and really meant to look for something so many others generally look for which is usually entirely different...
... ;)
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But I have the feeling that google is much better in understanding me and the words I am typing then 5 years ago - may be it got to know me (this is probably a real thing).
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Heh, it very much is a real thing! I betcha if you and I did the exact same search we'd get different results, even if we searched from the same (.com vs .de) engine...
Which is all well-and-good, but makes things difficult when trying to interact with others... "just Google it, dumbass!" The new "RTFM" in an era wherein "TFM" changes based on *who* reads it.
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Hm, I think the rolling shutter definitely plays a role Here.
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right... "aliasing"... but assuming that "shutter" rolls at a constant rate, rather than, say slowing between the visible peaks on the string's vibration...
Note, also, the orientation of the camera is vertical... I bet we'd see a *very* different effect if it was horizontal.Had a buddy back in the day did something like this with a TV, stretching a string vertically across a white screen... was interesting, but I don't remember seeing "spikes" like these...
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I got stuck on all the real vs. fake stuff, made me yell "real because shutter" at my tablet at 4am ... sorry :D physics of guitar strings, I should know this stuff better, but I think the waveform does also change depending on where you pick the string and it's composed of multiple wavelengths, so the spikes are looking right. Here's a guy with an oscilloscope (==camera/shutter?) and a guitar.
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Hah, I disregarded "fake" right off the bat ;)
I see a very similar waveform in this video, but also am considering the pick-up isn't showing 3D motion of the string itself, but showing a 2D plot of the magnetic waveforms it's detecting... And, that's probably not even a 2D-projection of the 3D image :)
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it's like standing in a cloud of flies, clap all around you and look at your arms afterwards to check distance vs. fly density - you'll never be able to tell where the fly was in 3D, only in 2D. That's one of my weirdest comparisons and I'm so proud of it. Folding 3D space into "2D" with your arms. Almost like crafting. :D I need food and coffee.
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I dig the visual.
I can *almost* wrap my mind around this one right now... I too need food and coffee.
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