Gregory's Server
 131 comments
 @Bit_form CDs read from the inside out, so yes, theoretically that works as long as there is no data in the part that has the grooves.  @slyka cool project! Might be something for @zeno4ever with Hackfest @hackfestnl?   Yeah, that was what I was thinking: A side for digial, B side for analog. I mean, aside from the whole diameter thing, of course. Flip-side (heh): haven't they also come up with optical readers for vinyl? Expensive af, iirc, but it's a thing? I thought the aluminum coating was *inside* the plastic shell? Maybe it's the double-sided ones I'm thinking of. (It may be apparent that I've never looked closely at CDs.) @cavyherd for a CD the coating is on top, covered by a thin layer of lacquer. For DVD's it's sandwiched between two thin plastic disks Oh. Dust. Right. Which tend to, uh, alter the vinyl, ahem. Interesting. I would expect some degree of algorithmic correction could address that? Probably too late in the game/too low volume to be worth it, but I'm a little surpised no one's come up with non-static vinyl.  @mdione my favourite! real talk though, the whole inspiration behind the machine is to make small runs of bioplastic based records that don't involve the general nastyness of traditional PVC based records    Awesome, would be really useful to re-use CDs as dubplates.  @revk CDs play from the inside out, so yeah, as long as there isn't any data in the area with the grooves   @slyka @miunau CD players were always promised to be able to ignore scratches, I wonder if they are able to read through this intentional scratch. @leeloo but… that's exactly what I did in the video? Wether or not the it's a CD-R or a normal CD makes no difference in the layer stackup :blobfoxconfused: @leeloo I don't have anything to read CDs with anymore, but I doubt it. Even though there is some amount of error correction in CDs this basically completely covers a continuous section of the surface in relatively deep scratches @leeloo it's still an interface between two materials with different refractive indexes, which due to the grooves ends up at pretty steep angles. That's gonna refract the light all over the place wether it's focused on the interface or not. I'd love to be proven wrong but I don't really see that working too well     The material for analogue records is made from #vinyl for a reason. The addition of conductive carbon makes this material less prone to static noise caused by the needle running in the groove. However there are new developments like PET, but these are still expensive in the making. I still use a liquid with alcohol in a Lenco brush. Results in low noise playback and longer life of the precious diamonds.  @PaulNickson @slyka @miunau It would be cool if the analogue groove was cut on top of the original CD track (yes, from the inside out at CV) — but I think the original CD track would be too narrow.   @doragasu oh believe me, there was a lot of fucking swearing sometimes you gotta suffer for your freedom, or something  @slyka I first thought it's going to be some contraption that optically records an analog audio signal onto a CD the same way video is recorded on LaserDiscs @slyka Thank you for that detailed video description, I had no idea the platters on record cutters were thicker and made of concrete. Also wow you can really clearly hear the audio being cut. @pitermach well, they're not all made of concrete, but mine is. It's just the easiest and cheapest way to make something big and heavy in a custom shape. The old Neumann lathes had huge cast iron platters but that's kinda hard to DIY…  @slyka @miunau does the difference in material hardness make a significant difference? Edit even before tooting: 🤯 looking up material hardness brought me to a fascinating read on styli where I learned that at the high end they're made *with the direction of the crystal structure of the diamond factored in*. https://thevinylpress.com/the-finish-line-for-your-phonograph-stylus/ @fencepost difference between what? PVC and PC? Idunno… PC is softer, but really tough. It does flow under high pressure, which is why it makes for good blanks for this specific process where instead of cutting a grove it's just embossed into the disk  Since CDs write center to outer edge, and records edge to center, you can mix-mode these. @teajaygrey you mean the lathe I used to make the parts? Or the model of the record lathe? I designed and built that myself from scratch  @lutzray are they? unless I read the specs wrong the right channel is cut on the top-left to bottom-right axis and the left channel is cut on the top-right to bottom-left axis @slyka sorry, it was tongue in cheek 😏 ... In your (cool!) video, the letter R was on the left and the letter L was on the right.  @th LaserDiscs/DiscoVision are already analogue*. ;) *if you ignore how mid 1980s and later LaserDiscs had digital PCM audio and even encode AC3 and other surround sound digital audio e.g. DTS (typically in the left channel analogue audio track which would sound like static if you, like I, had the misfortune to own a LaserDisc player so old, it didn't support any of the digital audio standards). Might be a useful way to repurpose LDs which suffered from laserot?  @keirFox thanks! This has been the last three years of my life more or less and it's incredible to finally see it come together  @slyka @miunau @amiserabilist Surprised it works because polycarbonate is so hard and brittle compared to vinyl.  @magnetic_tape The whole thing is gonna be open source once I'm done enough with it. CAD, software, firmware, PCBs, etc     Great work! It sort of reminds of one of the first scenes of the Russian movie Стиляги (2008) that shows how they made bootleg copies of records...using X-Ray film base: https://www.youtube.com/watch?v=UavmKtLIV3Y&t=126s https://en.wikipedia.org/wiki/Stilyagi_(film)#Historical_context  |
@slyka @miunau wha?