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Microscopic footage of a needle moving across the grooves of a record
- nate_meurer 11y agoWow! I never knew the needle move side-to-side! I always assumed phonograph needles moved up and down. Edit: Ben explains this in the video; there are actually two axes of movement, sort of diagonal to the plane of the disk, each of which encodes one channel of a two-channel stereo recording. I'm sure many LP fans already know this, but it's a revelation to me. BTW, Ben Krasnow is a heck of a guy. A true polymath and a generous teacher.
- arjn 11y agoYeah, I love his channel. Many hours of fun, interesting information and techniques.
- mturmon 11y agoPoking around on wikipedia (https://en.wikipedia.org/wiki/Compatible_Discrete_4 https://en.wikipedia.org/wiki/Compatible_Discrete_4), I learned that true four-channel quadraphonic sound, for LPs, was obtained by further recording two more signal streams in the same groove. These other channels were recorded with FM (frequency modulation) on top of a 30 kHz carrier. The 30 kHz carrier was just high enough to isolate the quad channels from the 0-15 kHz ordinary left/right stereo channels. And then, the FM portion, centered around 30 kHz, was added to the regular baseband audio signal (0-15 kHz), and all encoded into the diagonal displacements you mention in your comment.
- RegW 11y agoBrilliant - so that's how the my copy of Mike Oldfield "Boxed" (https://en.wikipedia.org/wiki/Boxed_%28Mike_Oldfield_album%29 https://en.wikipedia.org/wiki/Boxed_%28Mike_Oldfield_album%2...) was supposed to work. As I didn't have the cash to buy a quad player I never got to hear it in "Glorious quadrophonic sound", I had to use an "old tin box". It always baffled me that it also worked on an ordinary stereo - and I sometimes wondered if I had been had. We now have the tech to encode many channels in one MP4 stream, but don't we don't bother and just stick to 2 for sound. What does that tell us about the future of 3D TV and 360 degree video? Perhaps more of us will stick to the old tin boxes. http://www.discogs.com/Mike-Oldfield-Tubular-Bells/release/6284089 http://www.discogs.com/Mike-Oldfield-Tubular-Bells/release/6...
- dsr_ 11y agoNetflix sent me 6 channels for Daredevil, and the sound production was amazing. If you've only heard it via stereo, you missed out on all sorts of excitement. Good multi-channel sound immerses you in an experience, and is worth a significantly smaller screen as a trade-off, if you have to make it.
- cc438 11y agoThat's the perfect movie for demonstrating the potential of multi-channel audio. The only problem is that you're also relying on the viewer to have proper speaker placement, sound levels and speaker calibration. Autocalibration (YPAO) is simple and easy but hardly anyone knows to use it when installing their $300 home-theater-in-a-box.
- ghaff 11y agoMaster and Commander is another film with great surround sound. A number of years ago now, Dolby Labs used the sound from that movie as a showpiece in their SOMA theatre.
- chinpokomon 11y agoBrave? It was the first Atmos movie, so I've just assumed that the downmix to 7.1 and 5.1 is equally as good.
- wrigby 11y agoThere are some really interesting mastering techniques that are needed because of this, too - for instance, bass content (< 200ish Hz) on vinyl usually gets summed to mono to prevent a loud bass note on one of the stereo channels from making the needle jump out of the groove. With the loud bass content in mono, the needle jumps vertically and stays in the correct groove.
- deleted 11y ago[deleted]
- noilly 11y agoI've always liked this layman's animated FAQ: http://www.vinylrecorder.com/faq.html http://www.vinylrecorder.com/faq.html
- enf 11y agoLateral recording was a patent workaround. Thomas Edison had patented vertical recording and was not interested in licensing it to anyone else, so Berliner used the noisier, but available, lateral technique.
- coldpie 11y agoFuck patents.
- vinkelhake 11y agoThis is just blogspam. Link to directly to the video instead. There are a lot of videos worth watching on Ben's channel.
- cpach 11y agoHaving a written summary/introduction is quite nice IMHO.
- stilldavid 11y agoLike, say, the video description? "I describe how I made a stop motion animation of a phonograph needle in an LP groove using an electron microscope. I also show electron micrographs of other recording media."
- amelius 11y ago> You would think that if you have an electron microscope and a record player, you’re most of the way there to being able to record close-up footage of a needle traversing the grooves of a long-player record. Actually if you would have only an electron microscope, you could play the track without even needing the record player.
- xhrpost 11y agoThis has sort of been done with a flatbed scanner: http://www.cs.huji.ac.il/~springer/DigitalNeedle/index.html http://www.cs.huji.ac.il/~springer/DigitalNeedle/index.html
- exhilaration 11y agoIt's also available commercially in the form of laser turntables: https://en.wikipedia.org/wiki/Laser_turntable https://en.wikipedia.org/wiki/Laser_turntable and http://www.laserturntable.com http://www.laserturntable.com
- mturmon 11y agoAnd don't miss the part about the IRENE system, at the bottom of your wikipedia page: http://irene.lbl.gov http://irene.lbl.gov It uses microphotography of the disk surface, somewhat similar to that in the OP. They have recordings as early as 1860!
- udev 11y agoThe guy's diction is flawless.
- relik 11y agonoticed this as well.
- Panoramix 11y agoThis guy is a real jedi. Did he build his own Ag evaporator?
- eco 11y agoYes. That's not even though most impressive thing. He built his own scanning electron microscope (though that's not the one he used to produce these images). His channel is a lot of fun. https://www.youtube.com/user/bkraz333 https://www.youtube.com/user/bkraz333 I find it interesting that he worked at Valve until recently when he moved to Google X. He doesn't really talk about his jobs in his videos though.
- dzhiurgis 11y agoMy favorite is 'I've got this oscilloscope and wanted to test it, so why not do this in style and connect it to my DeLorean.'
- McElroy 11y ago>His channel is a lot of fun. Checked it out and I agree. I have to wonder, though, if his money shrinking experiment is such a good idea. Isn't that sort of treatment of currency prohibited by law?
- jonknee 11y agoIt's along the lines of the machines at tourist attractions that stretch out and stamp a penny.
- xigency 11y agoThe only thing is, the needle isn't moving here. This is an animation of what a needle would look like moving across a record, but taken in stop-motion style. I wonder if the use of an electron microscope is really needed? The grooves in a record are hardly small enough to escape visible light...
- PhantomGremlin 11y agothe needle isn't moving here That was my big problem with the video. I'd like to see real-time dynamic behavior of a needle and record. A static image every 10 seconds is not the same thing. Edit: here's[1] an example of what I mean. It's a slow-motion video of a topfuel dragster. Just positioning that dragster statically down a dragstrip and taking a picture every few feet won't show you the essence of what's happening. Look at the tires. Look at the vibration. Look at the flames. I dunno. Maybe my unease is not as relevant with something simpler such as a needle and record. [1] https://youtu.be/Lt6iltuxD48?t=120 https://youtu.be/Lt6iltuxD48?t=120
- beloch 11y agoAs the fellow states in his video, he was limited by the capabilities of the microscope. The quality of images he took required 10 seconds per frame. The microscope was capable of producing something much blurrier at 60 fps. You would need to record several thousand frames per second to produce something other than a blur when looking at a record producing audio in real-time. Human hearing extends up above 20 KHz and vinyl records are designed to handle this. Recording a normal object at tens of thousands of frames per second would require a very expensive camera and intense lighting. Doing this through an optical microscope would be substantially more difficult, and a current world class electron microscope would probably be incapable of such frame rates. The scale of a vinyl record groove and needle suggests that a good optical microscope would be sufficient. However, this appears to be a case of a fun project chosen to test out a tool, rather than a tool chosen specifically for the project.
- ealloc 11y agoMaybe you could use a strobe effect: Have an audio sample that loops every 1/100th of a second, and then put a "fan" spinning at the same rate in front of the electron source, which blocks the electrons except for 1/60th or less of the 1/100th of a second. As you vary the phase of the fan, you capture the needle at different positions in the loop.
- ianphughes 11y agoAm I the only one who could listen to him narrate just about anything for hours at length?
- moron4hire 11y agoBeen watching his videos for years now. He's great.
- deleted 11y ago[deleted]
- InclinedPlane 11y agoThe "root post" is just the youtube video itself.
- bluedino 11y agoNext up - laser hitting a compact disc.
- agumonkey 11y agoFirst time I get to see one of this legendary video vinyl ... Thanks.
- jokr004 11y agoI highly recommend everyone check out other videos on Ben Krasnow's youtube channel [0]. I've been following him for about a year now, really awesome stuff! [0] https://www.youtube.com/user/bkraz333 https://www.youtube.com/user/bkraz333
- JabavuAdams 11y agoFunny, I was just watching this last night. I'm in awe of the Applied Science guy, and am really grateful for the information he's shared. Having said that, I was shocked to see his thermite BBQ video. I don't know whether the people in that video realize how close they came to being maimed.
- bkraz 11y agoI am stoked to see my work on the front page of HN! Let me know if you have any questions. I've lurked on this forum for a long time, but rarely post.
- panic 11y agoIn the slow-motion video, there's a dark area to the top right that disappears partway through. What's happening to cause this effect?
- bkraz 11y agoI suspect the dark area was a piece of lightweight dirt (a tiny lint ball, or sawdust) that began accumulating charge as it was imaged by the electron beam. After 20 minutes or so (20 frames in realtime), the dirt developed enough repulsion force to be launched off the surface of the record. It's sort of like a charged comb or other object repelling styrofoam particles.
- Cantremeber 11y agoWould you consider selling posters of that needle shot as a way to support you? I'd love to get a poster of that to hang and I'd love to be able to fund you doing more cool stuff (your channel is great).
- ianphughes 11y agoThat's a great idea. He certainly would get my money.
- bkraz 11y agoThanks! I really appreciate it. My source image is 1000x1500, which redbubble.com says is not large enough for a poster. I admit, even at 150dpi, it wouldn't be much of a poster. As I upgrade my SEM image acquisition hardware, I'll be able to make higher res images. If you'd like the raw PNG, check out my blog: http://benkrasnow.blogspot.com/ http://benkrasnow.blogspot.com/
- daniel-levin 11y agoThe YouTube channel [1] where this video comes from is a treasure trove for the intellectually curious, and it's one of my favourite things on the internet. The guy behind it, Ben Krasnow, is an engineer at Google. From explaining and demonstrating (reverse) spherification to encoding information in fucking fire and picking it up with his oscilloscope, this channel will interest and delight most folks who enjoy HN for hours. [1] https://www.youtube.com/channel/UCivA7_KLKWo43tFcCkFvydw https://www.youtube.com/channel/UCivA7_KLKWo43tFcCkFvydw
- kitd 11y agoA bit OT, but this reminds me of an inspirational mathematics teacher I had, who loved to present the subject as a series of applied problem-solving exercises, rather than the usual learn-by-rote. One of his problems was: if a 33 1/3 rpm record is 12 inches in diameter and plays for 25 minutes, how wide is the groove? I had a clear visualisation in my head of the problem, including the groove cut into the vinyl. Watching this is like listening to my teacher speaking to me again.
- afandian 11y agoWhy was an electron microscope necessary? Surely at this scale a conventional light microscope would have done the job, wouldn't have needed all these workarounds, and could have recorded live footage of a needle actually playing a record?
- bkraz 11y agoIt's true that a SEM wasn't strictly necessary, but there are a few interesting features that make SEM images visually different, and perhaps more appealing, than light microscope images. The electron signal emitted by the surface of the objects in the chamber doesn't behave like light bouncing off an object's surface. Normally shadows are cast by photons traveling in straight lines, and our minds have become accustomed to this behavior. The electrons in the SEM can travel in curved paths, so the illumination in the SEM image can effectively go around corners, leading to surreal shadows and highlights. The aperture size in the SEM is much smaller than that used in a camera or microscope, leading to much higher depth of field for a given geometry and working distance. A camera might be f/16, while this SEM is effectively f/200 The brightness of objects in the image is partially influenced by the material properties and local geometry, so an exposed protrusion or edge will tend to be very bright -- something that doesn't happen with macro photography. Hey, it's fun to play with scanning electron microscopes.