If you'd take a photo of a vinyl record, what would the resolution of the photo need to be for you to be able to extract the audio from it?
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This would be such a cool side-project 👀
aug 30, 2025, 5:43 pm • 2 0 • view
the inner edge of a vinyl LP has about a 5 cm radius. assume the LP turns at 33 1/3 rotations per minute. that means at the end of the LP, 31 cm of groove will pass in, let's say, 1.5 seconds, or 20 cm per second.
aug 30, 2025, 5:53 pm • 3 0 • view
Assuming you want a fidelity of 20kHz, you'll want a resolution of 1/100 of a mm. I probably messed up some part of this calculation btw
aug 30, 2025, 5:53 pm • 3 0 • view
Interesting. Well, let's say there are 200 grooves per inch and 3⅜ total inches = 675 grooves, and let's say you want to be able to resolve the shape of the groove to 8-bit resolution, so you'd need 256 pixels per groove width, or 172,800 pixels each way... about 30,000 MEGApixels. So not easy.
aug 30, 2025, 6:34 pm • 1 0 • view
You might be able to cut that down by as much as a factor of ten and still have it listenable. I think the real trick would be setting up the right illumination to light up the whole disk in such a way that all the groove excursions were clearly delineated.
aug 30, 2025, 6:34 pm • 1 0 • view
The first sound "recordings" were made by a "phonautograph," a vibrating stylus scraping away lampblack from glass disk. Years after they were made, someone used photoetching to engrave it into a metal place and it then, for the first time, could be played back.
aug 30, 2025, 6:34 pm • 1 0 • view
I seem to remember a site where you could upload images of records and getting a sound file back, but I can't find it now...
aug 30, 2025, 5:46 pm • 2 0 • view
At any rate, it has been done, see IRENE at the botton of 'Laser turntable', en.wikipedia.org/wiki/Laser_t...
aug 30, 2025, 5:42 pm • 7 0 • view
en.wikipedia.org/wiki/Laser_t...
aug 30, 2025, 10:54 pm • 0 0 • view