How do vinyl records hold stereo sound? 

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23 Mar 2023



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Comentários : 2 514   
Technology Connections
Technology Connections 2 meses atrás
A CLARIFICATION: My script is missing two important words in describing the stereo groove: "behaves like." When discussing stereo-difference signals, I declared that that's what's on the record - which is arguably true but only when you consider lateral and vertical stylus movements in isolation. The raw L&R channels are still encoded as purely diagonal groove movement, but the phase difference in the the cutting head's actuators ensures that those movements, when combined and equal to one another, only result in lateral motion. The cartridge also has its pickups wired with the same phase arrangement to ensure the L&R channels are in phase with one another when playing a mono record (or the virtual center of a stereo record). Is that a mono signal in the lateral motion with stereo-difference information in vertical motion? Well... you decide!
Zaydan Alfariz
Zaydan Alfariz 2 meses atrás
Nice info, Alec! I'm Indonesian. We might have different taste regarding things. For instance, your video about electric kettle is certainly off-limit, not because of such thing doesn't exist because we have it too. But because 1300w kettle, let alone 3500w Europeans use, is way overpowered. We, like Italians, only have strict limit on electricity. Most of us only have 1.3kw. Yes, 1.3! Others have 2.2-4.5kw. Not bad, but not great either. There are also lots of people using 450 and 900w! If you try to use even the lowest end kettle with both types of electricity, you'll trip the breaker (singular, because most of us only have one) quickly. If you have middle class electricity (which is most likely the viewer of your video), you'll hit the limit quickly, and yes, 1.3kw kettle (assuming you have adapter for it) will instantly trip. Even on 2.2-3.5kw, 3.5kw kettle will trip that range of electricity. You have to be at least 4.5kw to be safe, which coincidentally the government persuade to make the transition to EV successful. For your video about can opener, nope, we don't use that. Instead, we have a thing called coconut grater. And heck, you can buy a f ing coconut grater machine if you want. And yes, it comes with electric variant. For the video about passive house, unfortunately, it doesn't gain traction here, even in SEA generally. We simply have surplus of electricity and we don't do time rate. So, noon power is the same as night power. The heat pump and related parts (water heater etc), and house insulation tho, we have it. For the EV, we do have the exact same Ioniq 5 model as yours, just with 250v. So, we're able to pull 3500w in a single cable. Overkill for most households tho. Same goes to electric stove. Tho again, 3.5kw per stove is simply insane to us. Most of us, if any at all, only have single 1 kW stove, mostly nonembedded (tho embedded/range variant do exist, but we have at max 3 stoves). Rest of us that don't have electric stove obviously use gas, which is the majority of stove even today.
Graham Rule
Graham Rule 2 meses atrás
Thanks. I was wondering about the phases since they didn't look right to me in your paper mode.
f.k. b.
f.k. b. 2 meses atrás
FYI - Your Closed Captions are one of my favorite parts of your videos!
Alexandru Voda
Alexandru Voda 2 meses atrás
Note, the same idea was kinda used for video too. Instead of using RGB for transmitting color video, we used YPbPr to transmit the black and white backwards compatible Luma and the difference Chroma channels for blue and red.
Joe Sterling
Joe Sterling 2 meses atrás
Thank you. I thought, either I have a huge hole in my decades-long audiophile knowledge, or . . . Great presentation regardless, as usual.
Archer 2 meses atrás
When you started discussing stereo difference channels using Audacity, it was very satisfying. I have a fun story about a radio station that did this by accident, causing me to make a curious detour on a job. Back in 06, I was at university, and also working for the university's media department. They wanted to play the campus radio station over the ceiling speakers in the lobby of the student union, so we put a receiver in a closet and connected the signal. Only -- the ceiling speakers weren't in any kind of stereo configuration; the whole array was driven off the same mono signal, so we had to pass the radio station through a little downmixer. At first I didn't have the part with me, so I just shoved one channel through the speakers to test them, and then I went and got the downmixer to install. When I did that, I found the audio almost totally went away. I checked the wiring and I hadn't messed up; everything was connected the right way. The level indicator wasn't zero, though, so I went from the closet into the lobby with the volume turned up and it sounded like I was underwater. The signal was there, but coming out mud. I tried a different source signal, and it came out fine (after I almost blew out the speakers from nearly forgetting to reset the volume levels). That's when I had the thought, "oh crap, the radio station, they're broadcasting their stereo channels 180 degrees out of phase." One of my roommates had a radio show and worked as a technician at the station so I told him about it. To prove what I was saying, I captured a segment of the station's live Internet stream, which I knew from my roommate was driven off the same mixer as the FM broadcast, and the software I used to capture it was Audacity. All I had to do was combine the left and right channels -- without having to invert one -- and play it back. "I think you've got something wired backwards," I said. We went into the station the next morning and fixed it. They were using analog audio equipment, not digital mixers, and at some point the polarity of one channel had been reversed in the feed. That is the first time in my life I got to fix something by reversing the polarity, and it did satisfy a good chunk of the childhood engineering dreams I had since watching ST:TNG at age 3.
Name Surname
Name Surname 2 meses atrás
when one of the channel is inverted (which could also happen when speakers are connected in reverse) the center is removed, so i thought i found a karaoke mode (doesn't work for all songs)
David Walker
David Walker 2 meses atrás
Doctor Who would be proud
Jochen Stacker
Jochen Stacker 2 meses atrás
And you didn't even have to route it through the main deflector dish. 😜
Martin Roe
Martin Roe 2 meses atrás
Something like that happened to me once. i replaced the cartridge on my turntable and and mistakenly reversed the wires to one of the channels. Took out the center channel until I figured it out.
Link Skywalker
Link Skywalker 2 meses atrás
I plugged in the headphones into the headphone jack, enough that sound will be loud and clear, but not all the way. I could be wrong, but when I did that, I think I may have been listening to the stereo difference channel.
wolfgang 2 meses atrás
I'd be super interested in hearing you cover quadraphonic records.
8546Ken 2 meses atrás
I did see a video about quad. Not sure who, You can do a search.
Ramenvas Mês atrás
Matthew B
Matthew B Mês atrás
Jed Kronfeld
Jed Kronfeld Mês atrás
Mike Solo
Mike Solo Mês atrás
came here to say this^^^
rj Mês atrás
i've worked at a record store for 8 years now and the technology behind vinyl still blows my mind thank you for doing this
Dehv Blak
Dehv Blak 14 dias atrás
digital wins!
John Clarke
John Clarke 8 dias atrás
@Dehv Blak Analog is more fun.
Bradley Buyer
Bradley Buyer 2 meses atrás
Vinyl record trivia: Monty Python (back in the day) cut an album that had two sides on one side: Each 'side' was cut in one spiral grove right next to another spiral grove. Depending on how you set the needle down, you'd get one track or the other. They had no mention of this on the album notes, just left it for you to figure out. Of course, each track was half the length of a regular album side. Crazy!
True River
True River 2 meses atrás
I think it was the same album, certainly it was Monty Python, where they recorded into the end loop of the record, at the end of a sketch where a protection racketeer scratches the record. The last few words of the side are "sorry squire, I scratched the record, scratched the record, scratched the record, ... " which repeated ad infinitum until you got bored. The end loop was larger than usual so that the record deck did not realise the record had ended.
Retro Tech
Retro Tech 2 meses atrás
…which would have been another approach to stereo. Emory Cooke tried an outer and inner track for stereo with a forked tonearm with 2 mono pickups. It didn’t work that well and neither that nor concentric spirals like the Monty Python record (nor true vertical / lateral stereo) would have been backward and forward compatible.
3rdalbum Mês atrás
Techmoan did a video about a "horse race" record; it had four different grooves on the one side, each groove containing a different commentary of a horse race with a different winner.
denelson83 Mês atrás
Matt W
Matt W Mês atrás
I remember Tower Records selling a not-as-expensive-as-you'd-think box of CDs of the complete Wagner's Ring of the Nibelung. It came shrinkwrapped with a simple control box with a knob to fade the output from the CD player completely left or right (placed between the CD player and the amp I presume). Instead of the 10 CDs the 15-hour epic opera cycle would normally take up, it only used a paltry 5 discs 😀
Daegan Noel
Daegan Noel 2 meses atrás
I never expected Alec to add papercraft to his list of tools to explain with but I am ALL for it!
Captain Chaos
Captain Chaos 2 meses atrás
This technique is still a thing in digital recordings. In a "joint stereo" MP3 encoding, the sound is encoded as a mono channel and a stereo difference channel. The reason is that it compresses more efficiently and results in smaller files for the same quality.
rfmerrill 2 meses atrás
The most common terms for that are "mid" and "side" channels (and the transform called a "mid-side transform")
5mf1nc 2 meses atrás
not the same quality, that's the point: you sacrifice stereo separation to more detailed "mono" components -- only problem is, the stereo difference is not nearly as musical as the mono part, but the encoding does not use significantly different method to encode it, so you will lose a LOT of stereo details (also, some encoders insist using heavy low-passing, at least below certain bitrate mangling the sound even more)
Joel Hjertén
Joel Hjertén 2 meses atrás
Can you still record two completely different mono track on each R an L channel. Say one song on the left and another in the right and hear them completely separated, like if you isolate and only listen to the L chanel?
Andy Krew
Andy Krew 2 meses atrás
This is how FM radio broadcasts in stereo as well. The baseband signal in order is L+R, pilot tone, L-R, RDS encoding, then supplemental services.
Greybell 2 meses atrás
huh i didn't know that's what joint stereo is. i thought joint stereo turns mono signal into a fully mono sound while still retaining the remaining stereo channels.
Aaron Tuchardt
Aaron Tuchardt 2 meses atrás
Loving the inverted credit music haha! Phase cancellation is essentially what we’re listening to. The difference between the sounds that isn’t cancelled. Love the video!
Stephen S
Stephen S 2 meses atrás
this difference in channels is what hafler used to produce a pseudo quadrophonic sound simply wiring a speaker or two across the positive terminals of the amp output. i have been using this for decades to add depth to the stereo image.
TankMcHavoc Productions
Fun fact about the mono and “stereo difference” signals (better known as mid and side): There is a drum micing technique built around this principle! If you take a cardioid mic, and put a bi-directional mic right next to it, but pointed perpendicular from the sound source, you can get stereo drums that collapse perfectly to mono. Simply add the two signals together in one channel, then subtract the bi-directional signal from the cardioid in the other, and you have stereo drums!
Roxor128 2 meses atrás
You can generalise the technique. Split the cardioid into an omnidirectional and a bidirectional pointed forward and add another bidirectional microphone pointing up. Your resulting set of four signals can represent a full sphere of sound. It's known as first-order Ambisonics. BRvid uses it for the audio component of 360-degree video.
Craig Hamm
Craig Hamm 2 meses atrás
There’s nothing inherent to drums about this. I use mid-side to record piano, and even orchestra. I like it because you can adjust the stereo sound in post.
Alister Carmichael
Alister Carmichael 2 meses atrás
Very common for video and broadcast from the beginning of stereo t.v. to maintain compatibility with mono tellys. Still used in many budget video mics, but the mix matrix is on the mic so you get L&R out rather than M&S. Some are switchable while others are not.
Jonathan Pearce
Jonathan Pearce 2 meses atrás
@Alister Carmichael Still something of a standard for TV and radio broadcasts of orchestral performances. Often with a very very nice Schoeps M/S rig.
denelson83 Mês atrás
Don't get us started on the ORTF stereo technique…
Chris Goosman
Chris Goosman 2 meses atrás
What a great video, Alec! As a mastering engineer and former lacquer cutter, I think you did a fantastic job explaining the process. The construction paper model was a perfect visual aid! Bravo!
striker1553 2 meses atrás
Thelma Houston and Pressure Cooker was the first direct-to-disc record that was done without breaks. In other words, LIVE. The only break the band and singers got was the 30 seconds or so before the next song was supposed to start. Also, the break they took between sides of the LP. Well worth a listen!
Robert Romero
Robert Romero 2 meses atrás
I had direct to disc records. They were considered the best the format had to offer. CD essentially made them obsolete. Doug Sax of Sheffield Labs had a horrible case of sour grapes about this fact.
Dan Petitpas
Dan Petitpas Mês atrás
@Robert Romero Technically, all discs before 1948 were direct to disc, until recording on tape came into the picture.
Robert Romero
Robert Romero Mês atrás
@Dan Petitpas True, but the associated equipment wasn't as good back then.
E 20 dias atrás
Also, check out James Newton Howard and friends ( some of the Toto guys )
Christian G
Christian G Mês atrás
Your closed captions are just A++! Such a small detail that screams attention-to-detail! Love your content!
Randy Dean
Randy Dean 2 meses atrás
BTW, fantastic job on describing the audio in the captions! Many people never seem to get that captions are more than just what words are being said...
name 2 meses atrás
Yeah! The words of the script read aloud are usually pretty good image descriptions too
Marshall Halleck
Marshall Halleck 2 meses atrás
I was literally laughing out loud at them they were so on point and clever.
Bun Bone
Bun Bone 2 meses atrás
Thanks for reminding me, I keep forgetting which channels have the good captions or not.
John Crafton
John Crafton 2 meses atrás
The confusion goes the other way too. I'm always annoyed when caption information finds its way into subtitles.
Nappse 2 meses atrás
Oh noes! This is Primitive Technologies all over again. Me watching all the videos one more time not to miss out. 😂
Lucas Mês atrás
I was actually listening to a record when I realized this is how it worked! The snares on Todd Rundgren’s A Wizard A True Star are intentionally put out of phase, but panned hard left and right. Listening back to the cd, it sounds like normal out of phase, and in mono it disappears. But on the vinyl, it gets a really weird, unique spatial quality to it as the needle fights with that huge Side channel! I love weird Mid-Side tricks like that, and in other music where listening to it in mono will ‘erase’ certain vocal lines
Guest Invitado
Guest Invitado Mês atrás
I grew up with LPs during the 80s. By then, fine audio equipment was available at a reasonable price. Speakers with fifteen inch kickers were very popular. Listening to the left and right audio was an experience. Even to this day, stereo is one of the greatest inventions of all time. Very interesting video, I enjoyed it. Thanks!
Dominic Perez
Dominic Perez 2 meses atrás
My favorite part was the stereo - difference outro. 😁 I love hearing things that you can't normally hear hidden in the stereo - difference channel.
Privatepilot 2 meses atrás
I’ll throw you a curve. Look into quadraphonic vinyl LPs. Played with the infamous “Shibata” stylus! Quite interesting and actually produced exceptional sound. However, not 100% analog of course, but still very advanced for the era in which they were introduced. Great video!
Greg Roberson
Greg Roberson 2 meses atrás
The quad recordings used a 30,000 cycle carrier frequency to modulate the rear channels. The problem was the best quad stylus in the world couldn't keep up with the groove and would wipe out the record in about five plays, leaving only the front two tracks.
Privatepilot 2 meses atrás
@Greg Roberson Yeah, I would play my quad LP when I first got it to make sure there were no defects and the second time I played it I would record it to reel to reel. After that I’d file the LP into my collection. Most of my quad LPs only had two plays on them. I run it through a Kenwood KR9940 receiver. I wish I still had that setup.
Greg Roberson
Greg Roberson 2 meses atrás
I did the same and recorded on a 4 channel Akia. I lost most of my equipment during the '94 Northridge earthquake. I was living about 2 miles from the epicenter and the only room that sustained damage was the theater room.
Nick Wallette
Nick Wallette 2 meses atrás
Mono and Difference channels, or "Mid / Side", are the key to so many things we use every day -- most of the time, because of backward compatibility with older standards, or where we just want mono compatibility. FM Stereo and analog TV audio both work this way (similar to TV's Y / Cr / Cb color encoding.) Some digital audio encoding formats still use this as an alternative to L/R encoding, for various reasons. MPEG, for example, and probably many of the other perceptual encoding schemes, due to compression algorithms having a particular affinity for correlation. I sometimes track stereo audio (like two guitar or vocal tracks) as a mid and side track, then convert them to L/R using polarity inversion. Again, that helps to ensure the result will work if folded down to mono, but it can also sound interesting (sometimes better, sometimes worse) when there are differences in the takes. This two-channel phase relationship is also one of the core principles to how Dolby Pro-Logic Surround works -- the center channel is from the Mid, the rear channel is from Side, and L/R vs. M/S are steered using some fancy analysis of the signal to determine which direction (front/back vs left/right) is more prominent.
Ned Hedrick
Ned Hedrick 2 meses atrás
Fun stuff. I'm old enough to remember the coolness of the original stereo records. But honestly, what really WOW'ed me was "quadrophonic" records. That could also be an interesting follow-on to this...
borstenpinsel 2 meses atrás
The moment he said and showed "stereophonic" I immediately thought of that as well. That would indeed be a very interesting topic.
Max Oakland
Max Oakland 2 meses atrás
I would love to know more
ilRosewood 2 meses atrás
Uh, yes please
Toweri Li
Toweri Li 2 meses atrás
Not to mention "Ortoperspecta", invented by Tapio Köykkä, a three-channel (Front-Center and L + R Rears) reproduction from a regular stereo signal. Center channel was the sum of L and R, while the rear channels reproduced the differential signal.
Lawrence D’Oliveiro
Lawrence D’Oliveiro 2 meses atrás
There were two different quadraphonic systems. There was SQ, a “matrix” system which didn’t really have four separate channels, and there was JVC’s CD-4, which used subcarriers to encode either the rear channels or front/rear difference signals, not sure which. This gave better channel separation. I remember reading a bunch of Sansui brochures at the time. They took SQ and turned it into “QS”, which some kind of dynamic level-based adjustments of the decoding matrix, to give the effect of better apparent channel separation.
AntiChangeling Mês atrás
As someone who is deaf in their left ear, this has actually made me interested in getting a mono stylus. I listen to almost everything in mono so that I don't miss anything, and it'd sure be convenient to only need one speaker, rather than two - especially if I have a smaller space to work with in the future. I have no idea whether it'd actually work the way you'd describe with modern records, but it'd be interesting to find out.
Jibran Khan
Jibran Khan 15 dias atrás
A mono stylus wouldn’t do what you’re thinking of, I think. A mono switch would, however.
Ivan Moskalev
Ivan Moskalev 2 meses atrás
Just found your channel. Absolutely loving this, please keep up the great work! Great explanations, great overall mood, great music - amazing.
Alvaro Sundfeld
Alvaro Sundfeld 2 meses atrás
You can pick literally any kind of subject, and talk about it in so much detail… that is the best explanation about stereo records I’ve ever seen in my life!
Roy Riederer
Roy Riederer Mês atrás
I remember experimenting with the album 'Dark side of the Moon' back in 73. With the song 'Money' if you disabled the right or left speaker, you would still faintly hear the right channel on the left side and the left channel on the right side. That song has very distinct stereo sound so it was easy to experiment with. Back then I had no idea how the sound was recorded, just that I could easily manipulate it. This was a very good video with a solid explanation. I enjoyed it very much. 👍
Tony  E.
Tony E. 2 meses atrás
Great video, I always wondered how you get sound or music out of a piece of vinyl. Excellent history and technology behind it all. Thanks! 😃
Paul Martin
Paul Martin 2 meses atrás
A tip for anyone doing restoration of stereo audio off records. Because dust and crud sits in the bottom of the groove, it proportionally affects the stereo difference signal more than the mono signal. Convert from LR to MS then do your de-clicking etc. on each separately. Be careful not to use anything that might affect the phase relationship between the two signals. Then convert back to LR after processing.
mjanovec 2 meses atrás
The stylus tip never rides in the bottom of the groove. Styli have the tip rounded off, so only the sides of the stylus are in contact with the groove walls. The very bottom of the groove is typically not in contact with the stylus. One trick you can use with worn records is to use a stylus with different radius than the one that caused the wear, making the stylus ride higher or lower in the groove to find a portion of the groove wall that is unworn. This trick is regularly used by audio engineers transferring rare recordings from old 78s.
sevenbark 2 meses atrás
"Convert from LR to MS" - could you unpack this a bit? I assume LR = left-right, but I'm having trouble with MS
Paul Martin
Paul Martin 2 meses atrás
@sevenbark MS = Middle (mono) and Side (Stereo difference).
Mike Brown
Mike Brown 2 meses atrás
I've seen this advice for years, but every time I have tried this in Adobe Audition, it does not produce better results than just declicking normally. Perhaps its declick algorithm is already doing something like that anyway.
Paul Martin
Paul Martin 2 meses atrás
@Mike Brown Quite possibly. I've found it useful in Audacity.
theSpackster 2 meses atrás
I've always known mastering for vinyl was a more specific process, but after seeing how stereo sound works in a record player, it now makes sense! Awesome video! (Also big fan of the channel in general, this one was especially interesting to me as a hobbyist music producer)
Wolf Robots
Wolf Robots 2 meses atrás
i LOVE when you come out with a new video. That's because all of your videos are perfection and in reality should be used in universities.
David Shaw
David Shaw Mês atrás
Congratulations in creating such a clear and concise explanation of stereo LPs. One reason for its continuing popularity is its simplicity. Providing basic care is taken through all stages of recording and playback (e.g. keeping the LP clean and scratch free) excellent reproduction can be achieved with relatively basic equipment. Whereas the digital recording process is very complex involving a lot processing and despite its high spec can sound a little mechanical and sterile in comparison. Thank you for crediting Alan Blumlein, one of the most important engineers of the last century in many fields including RADAR, the invention of Ultra Linear amplifiers, improving undersea telephone cables and many others. Largely unknown probably due to his secret military work and untimely death in 1942 at 38 years old in an air crash whilst testing HS2 RADAR. He had achieved 128 patents.
Eclectic Feedback
Eclectic Feedback 2 meses atrás
Love this video, thanks! So about 1,000 years ago my brother & I spent the summer with our grandparents & they just had a mono record player. Magical Mystery tour was a new LP & we played that record a LOT. When we got home we were blown away because we now heard the full stereo on my Dad's piece of furniture stereo. So I'm still not sure why that would be as the two tracks were pretty much isolated when played on the Mono record player. I seem to recall something about how some of the FABs recordings were mono then later somehow enhanced for stereo by boffins.
Ben 2 meses atrás
This all still blows my mind how simple yet complex records are. Also thanks for having the outtakes.
David McGill
David McGill 2 meses atrás
That concept would also be used in FM radio broadcast. The combined channel is the main band while the difference channel is a side band. When the signal strength is weak the radio will swap to mono to retain quality.
rjhelms 2 meses atrás
Yup, and for basically the same reason - the technology existed in mono first, so transmitting the stereo as a difference channel in a sideband kept the transmissions compatible with older receivers. Come to think of it, it's the same thing they did with color television, just with a "color difference" channel instead of a stereo channel.
Ken Smith
Ken Smith 2 meses atrás
@rjhelms Technically on US analog TV it is "color difference channels". The 3 primary colors are encoded as two signals in the sideband channel. The two signals in the sideband are encoded on the carrier in two different phases. Those colors you see are made with more adding and subtracting than if at first obvious.
Doug Browning
Doug Browning 2 meses atrás
@rjhelms Actually, in NTSC TV two 90 degree separated difference signals carried the colour. G-Y and R-Y. Add G-Y to Y to get red, R-Y to Y to get green, then subtract red and green from Y to get blue.
David Calman
David Calman 2 meses atrás
@Doug Browning PAL rotated them so they're equally important and it's that version (YUV) that is used in early digital codecs.
Jonathon Shane Crawford
I was taught for FM Stereo, they switch _very fast_ between the left and right channels and TX the stereo pilot signal at a high audio frequency that 90% can;t hear! And also if the pilot signal isn't present, the RX will automatically turn it into mono!
Moocow2oo 28 dias atrás
As a person that I starting a record collection I asked myself this very same question just about a month ago. Thanks for being here to answer it!
Ron Dear
Ron Dear 2 meses atrás
Great video, as always! Did you know that Ben over at Applied Science has an amazing scanning electron microscope animated gif of a stylus moving in a groove! It really shows the 45 degree stuff you were talking about!
AMD Semporn
AMD Semporn 18 dias atrás
Fun fact: I often accidently heard only the stereo difference: When the headphone jack is not plugged in all the way, and both channels have contact but not the ground, you hear only the differences between the audio channels. Happened a lot in the good old days with mp3 players
RSpudieD 2 meses atrás
It's such a cool concept to fit two different channels in one grove like this. I heard about it a while back but your explanation really helps. I'm always impressed with vinyl and how it's physically storing sound but the concept of stereo sound like this is just crazy to think about! Genius! Great video as always!!
Chaos Corner
Chaos Corner 2 meses atrás
Stereo difference (along with some frequency filtering) is sometimes used to generate Karaoke tracks as the singer is typically placed in the center of the stereo stage while instruments are distributed. There are some Karaoke machine chips with this functionality built-in.
Nael Blogger
Nael Blogger 2 meses atrás
I was surprised that this was not mentioned.
The Phantom Channel
The Phantom Channel 2 meses atrás
This is indeed true. Anything that is mixed mono will effectively cancel itself out and since most vocals are panned center/ mono they will be "extracted" from the mix when isolating the difference. This is exactly how all "surround" processing works from a stereo source. David Hafler while working for Dynaco came up with a passive analog circuit which could extract the "difference" channel from a stereo signal and then send that signal to dedicated "surround" speakers. Dolby pro-logic is the exact same process just done with digital circuits but functionally identical with the exception that with digital you can alter the timings between channels to compensate for speaker placement and distances.
cobrag0318 2 meses atrás
I remember the sound editor that came with the packaged software included with our sound blaster 16 on our 486 could do that. Though most profession karaoke setups are actually worse than that, often being simple covers done by the production company, often with cut runtime, and sometimes even being performed on cheap synths, like someone's toy Casio keyboard. Lol. I'd imagine this reduces the licensing costs, as opposed to the original studio recording with the vocals filtered out as you suggest. I wish it were the case. Though I have on occasion heard some that seemed to be just that, where you can hear the faint remnants of the vocals if you listened hard enough. And even on a rare occasion, one that sounded like they actually got a hold of the masters and just mixed it without the vocals from the beginning. But sadly, by far, most professional karaoke discs seem to be the crappy covers by their in-house musicians.
Two Sorts
Two Sorts 2 meses atrás
@Nael Blogger Probably wasn’t mentioned in the Wikipedia article.
LS 2 meses atrás
A crude version of this can be acheived by connecting the speakers incorrectly. I'm sure there is an audio term for this. I don't remember if it involves connecting both positives to one speaker, or both negatives. Discovered this after accidentally wiring up some speakers the wrong way and suddenly revealed a song I liked had a distinct bit of lyric effect audible this way while nearly inaudible on the normal stereo version. It was quite fun.
Robert Basilio
Robert Basilio 2 meses atrás
I loved all the attention to audio production detail, and the captions, and the audio technology. This has been one of my favorite videos so far!
Tanuki 2 meses atrás
I would love to see a microscopic view of the groove to show the difference between mono and stereo records.
Mairsil Pretner
Mairsil Pretner 2 meses atrás
One other advantage of this set-up you didn't mention is that the stereo-seperation signal is generally much less intense than the "main" signal, meaning most of the motion of the stylus is still side to side. If there were intense signals in the up and down direction, this would pose a much bigger risk of launching the stylus out of its groove with loud sounds.
rockradio928 2 meses atrás
An interesting trick on a turntable is to swap the polarity of one of the cartridge channels and mono the amp. Interesting effect where only difference between left and right is heard. On records with lots of separation the main vocals, bass and drums usually disappear as they are normally in centre of image. Often you can hear backing vocals and instruments not heard before. Works well on Beatles.
GearboxEnt 2 meses atrás
Holy wow, Down To The Moon, what a throwaback! It, and other Vollenweider albums like White Winds, were a huge part of the soundtrack to my childhood. I'm pretty sure my dad wore out those tapes (yes, we had them on cassettes so we could listen to them on road trips - cars didn't have CD players in the 80s, kids). Thanks for the blast from the past!
Derek Loudon
Derek Loudon 2 meses atrás
Here I am, retired and in my 70s with a lifetime (well almost) in electronics and it never occurred to me to question how stereo sound works on a vinyl record. Thanks for the ‘training session’.
andygozzo72 2 meses atrás
its known as the 45/45 out of phase system
Lou Pasternak
Lou Pasternak Mês atrás
I had no idea. Before the internet, these were deep dark secrets
m p
m p Mês atrás
I remember some years back there was a fellow who could "read" vinyl records by looking at them and tell what piece of music it was. Granted (and by his own admission), he could only do it with classical music because he didn't know other styles, but impressive nonetheless.
TheVintageStuffGuy1998 2 meses atrás
Wondered how this works for years. Never could work out how a single groove could create stereo so glad to finally have an answer !
Matthew Parker
Matthew Parker 2 meses atrás
You can get some really interesting audio effects by engineering in sum-difference stereo instead of left right, or by applying tools designed for one encoding to the other.
isaac Mês atrás
You can use the MSED plugin for easy stereo separation of audio. Really useful.
Thomas Ireson
Thomas Ireson 2 meses atrás
An awesome video as usual! I loved the paper diagram of how the needle and pickups work together. It really helped me understand the process occurring to generate sound from the lp. Thanks for all the wonderful content you put out! I always look forward to your new videos and haven’t stopped talking to people about dishwasher detergent and brown haha.
Marshall Halleck
Marshall Halleck 2 meses atrás
Once you broke out the model everything clicked. Getting to see what the actual effect of the technique was really helped cement how they work at the same time, and how that translates to reading the groove. I remember watching your first video and, while I came away with both tracks being stored at a diagonal to each other, sharing a groove, I couldn't tell you why. I feel coming away from this that I could actually explain why they are at a diagonal and that feels fantastic. The followup about the stereo difference was also really cool and, from a completely different perspective really helped me understand what the record is effectively encoding. "Two different tracks at 45 degree angle to eachother" is hard for me to understand how that translates to a record, but taking that extra step to explain how effectively it leads to a mono track being preserved in the lateral movement with stereo difference in the horizontal it really got it from a technical understanding to an intuitive one. Thanks for another great video!
MonkeyJedi99 2 meses atrás
I love that the demonstration was arts &crafts instead of computer animation!
Regular Guy
Regular Guy 2 meses atrás
@MonkeyJedi99 YES!
電羽ひかる Mês atrás
This "L+R and L-R" thing also becomes useful in stereo FM broadcasts (transmit L+R as regular mono FM, then L-R as a suppressed subcarrier,) and later in color TV transmissions.
Thomas Kaldahl
Thomas Kaldahl 2 meses atrás
I feel like you'd be a teriffic Intro to Linear Algebra teacher! You've basically described what a change of basis is in a way that is super accessible and tangible.
Graham Dunning
Graham Dunning 2 meses atrás
Also worth an honorable mention is the Pathe disk system - up/down grooves on shellac, sometimes called "hill and dale" records - patented as a competitor to Berliner sideways grooves. Obvious now why the Berliner system became the standard.
GCAT01 Living
GCAT01 Living 2 meses atrás
I love things like this. It's like some awesome analog technology in a steampunk fantasy world, except it's real.
Mck Idyl
Mck Idyl 2 meses atrás
Thanks for revisiting this topic. I appreciate the additional details and hi-tech visual effects. Grew up with phonographs, and still have my working 1908 Columbia Disc Graphophone.
manonanisland88 2 meses atrás
I love this channel because it makes me want to learn about things that I never thought I could have possibly cared about before the video was posted. Thanks for all the great content!
Simone Bernacchia
Simone Bernacchia 2 meses atrás
Something that came in my mind recently given the resurgence of vinyl records and the scarcity of printing plants: do a laser engraver have enough resolution and movement to create a record directly on a disc surface?
Danny’s DIY LIFE
Danny’s DIY LIFE 2 meses atrás
I love you brother I love your content and what you do give me so much information on technology throughout the past and present it's amazing all the stuff that I grew up with and I used to take apart all of this stuff I didn't know really anything about it but I knew how it works and watch your channels helped me clarify a lot of stuff thank you keep up the good work I'm proud of you bro. Technology connections
Daniel Sobral
Daniel Sobral 2 meses atrás
I'm absolutely shocked I never knew vinyl stored information on the walls instead of the grooves.
FEETERICAN 17 dias atrás
When I was a kid, I watched an episode of Mr Wizard showing how this works and had people at home make a stylus out of a piece of paper and a sowing needle taped to it. One of the many things I learned on that show growing up. He even did a thing using a flashlight on a movie projector to produce sound.
Jon C
Jon C 2 meses atrás
Another excellent video! And you're still at nearly 100% on stuff I already knew, but you're so good at telling the story that I watched the whole video anyway.
Artholos 2 meses atrás
Wow this is auspiciously timed. I’m literally building my own record lathe right now and studying this technology 🎉 Neat!
pqnet 2 meses atrás
I guessed most of it (horizontal axis for average, vertical axis for difference) but I thought they would be picked up as horizontal and vertical and composed later electronically. I would figure since horizontal and vertical axes may have a different dynamic range, the ability to electronically choose the amplification for + and - signals can help balance that. You could effectively do that with diagonal pickups as well (just by changing the angle, instead of being exact 45 degree) but would make manifacturing a bit more complex (and wouldn't allow for adjustment in the future when disk material changes would change the ratio).
Wadz 2 meses atrás
I've always wondered how they got stereo sound out of one groove and one needle. Thank you!
Emily Rose Lacy-Nichols
The stereo difference track is trippy! The bass guitar is all ghostly cursed, but the brass is really quite similar to the original…
殘風[mmis1000] Mês atrás
That basically caused by the wave length. A lower tone sound have longer wave length. Which makes matching the wave between two channel easier. In the other hand, high frequency sounds have short wave length and hard to cancel out. A little off phase and it's not cancelling but adding up. That is also why ANC headphones hardly do anything to cancel human voice but works perfectly on car noise.
Emily Rose Lacy-Nichols
@殘風[mmis1000] Thanks for explaining! That's super cool :)
Quinnobi 42
Quinnobi 42 2 meses atrás
The 'mono' plus 'stereo difference' channel arrangement as you called it is, I believe, called Mid-Side in the audio mastering industry, or at least is somewhat similar to that.
Perry Barton
Perry Barton 2 meses atrás
Nice touch with the stereo difference version of the closing music! 🤓 Back in the dark ages (‘70s) there was a device called the Thompson Vocal Eliminator which employed this very technique. Since the lead vocal was/is usually panned center, shifting the phase of one channel by 90° would cancel out the vocal, leaving only any reverb triggered by said vocal. I never actually operated one of those, so I don’t know if anything was done to allow the low-frequency sounds of kick drum and bass (also usually panned center) to come through unscathed.
jagmarc 2 meses atrás
In the 70s when you got bored with a record you lifted the tone arm up to find the little colored wires plugged in the cartridge and switched a pair of connections. Then you got a completely different mix, usually minus the vocals and bass
Gazdatronik 2 meses atrás
Yes. They had a variable bandpass filter that you could dial in to only modify only the vocal theory. My aunt had one, and in practice it was pretty much crap. But I suppose it got the job done enough.
Because I'm a fan
Because I'm a fan 2 meses atrás
Thank you for pointing that out, I didn't even notice the closing music sounded different! 😅 Playing it again it's very obvious it's weirdly off 😁
Chris Merklin
Chris Merklin 2 meses atrás
I used this process many times in my teen years when transcribing music in my DAW software and reorchestrating it with midi synths. The center cancellation helped to reveal some sounds that were hard to hear in the normal mix. But, yes, it would usually cancel bass too, so EQ’ing was involved before the cancellation process. I must add that it’s not a phase shift of 90°, it’s a polarity inversion of one channel of the musical content, similar in concept to a 180° phase shift of a sine wave added to the original sine wave - cancellation. Common-mode rejection, used in balanced signals like pro microphone signals to cancel common-mode interference that might leak into a long run. Balanced or differential signaling using this noise-cancelling property is also used in HDMI, Ethernet, and other well-known signals.
Perry Barton
Perry Barton 2 meses atrás
@Chris Merklin Yes, I misspoke. Polarity inversion. Thanks. 😎
Shamino0 Mês atrás
Great video. You might want to mention in a followup that the concept of separating the mono content from stereo separation content is not unique to vinyl. It's actually very common. This technique is known as "joint stereo" or "M/S stereo coding". Instead of recording the two channels (L and R) separately, you record the "mid channel", M, which is the sum of the two channels (L+R) and the "side channel", S, which is the difference of the two channels (L-R). The result can easily be turned back to the individual channels by adding them and subtracting them: (M + S = (L+R)+(L-R) = 2L. M-S = (L+R)-(L-R) = 2R). One common use of this encoding is FM stereo broadcasts. An FM broadcast modulates the M channel on the primary carrier and the S channel on a sub-carrier. If you are too far from the transmitter to get a clean signal, your receiver will pick up the primary carrier but not the sub-carrier, so the result will be a mono signal instead of the stereo signal. Which is why when you're driving and listening to a weak station, you will hear the sound switching between stereo and mono as the signal strength varies. It's also how your receiver can know when to turn the "stereo" light on/off - it depends on whether or not the tuner can lock on to the subcarrier that contains the S channel. Joint stereo is also used in many compressed audio formats, including MP3 and FLAC. This is because moving the common components of the audio to one channel and keeping the differences on a second channel usually gives you better compression ratios when compression is lossless and will produce better quality sound when compression is lossy. Another cool thing you can do with joint stereo signals is that you can boost or cut the relative volume of the difference (separation) channel. If you boost it before converting it back to the discrete L/R channels, you effectively increase the amount of stereo separation (the "wide" effect) and if you cut it, you decrease the amount of separation.
Casper S�
Casper S� 2 meses atrás
Very interesting. I must admit though, I really like the imperfect "living" sound of vinyl records. My digital FLAC/ALAC music is cleaner and more accurate, but I like the scratching sounds in my vinyl and the organic feel of it all
jasonsong86 2 meses atrás
There are records that contained 4 channels from 1 groove called quadraphonic. The 2 extra channels are mastered above hearing frequencies that can be de-modulated back to hearing frequencies.
acalthu 2 meses atrás
As a vinyl enthusiast this cleared some misconceptions I had held for years, and indeed questioned said misconceptions as well
Rambler Andy
Rambler Andy 2 meses atrás
Nice explanation. I particularly liked the paper cut-out simulation. A couple of things. The stereo signal that vibrates through the stylus and cantilever is, as you say, two channels being fed through one solid, and therefore the stereo signal cannot be completely separated. This is measured as Crosstalk, and phono cartridges have a specification that describes the cartridges ability to minimise it. Better designs do better. Of course, crosstalk isn't unique to vinyl records. The other thing - seeing as you used Audacity to describe one aspect, I would have liked you to illustrate RIAA Correction or Equalisation, which is something that is peculiar to the phono stage in an amplifier because the record groove is shrunk to cram in more record/play time. It means the actual output from a record groove is very bass light/treble bright and has to be corrected. [an Audacity simulation could have shown this very well]. No other input/output requires any correction. Perhaps, when the vinyl record virtually takes over the recording industry for a second time, you can add the last bit in another re-visit to the groove. 😊
Matt Robinson
Matt Robinson 2 meses atrás
The visual aid you made for the angled needle was super helpful for me. I couldn't quite picture it. You make very good videos.
Bob Sykes
Bob Sykes 2 meses atrás
Interestingly, perhaps, Blumlein invented that technique for use in recording a stereo sound-field using two (figure-eight pattern) microphones placed at 90 degree angles to one another, just like the placement of the cutter head drivers and playback coils on the photograph cartridge. Another stereo micing technique, M-S, for "mid-side" uses different microphone types, but the same math, a mono (mid) signal and stereo-difference (side) signal to capture the stereo sound-field. It's really interesting stuff they came up with back then!
Black Fist
Black Fist 2 meses atrás
I boggles my mind that someone can invent a form to translate sound into a physical recording and then convert it back into sound just with ingenuity, some paper, a pen and of course a lot of money. I pale in comparison when i find myself unable to use autocad to design something that barely works. Kudos to the people that make things that work.
Dr. James Olack
Dr. James Olack Mês atrás
Great explanation of information storage on vinyl and the extraction of that information by the stylus. Your lava lamp brought back a flood of memories from my high school days in the late 60s. Thanks for the flashback…
Adam Albrec
Adam Albrec 2 meses atrás
A relative of mine experimented in the 1950's with early LP stereo that required two separate records and turntables that had to be started simultaneously. He said there was a small dot you placed each needle on then turn it all on.
GorgoReptilicus 2 meses atrás
I love how you describe technology! Thank you 😊
657BIueArmy 2 meses atrás
For some reason I am always more in awe of materiel methods of creating magic than electronic ones. The groove in a record has always struck me as remarkable, not only in that it works at all but how exactly it achieves it. Too few people are aware that it is a 90 degree difference in the two channels, and that the groove isn't shaped left and right for the two channels. I admit I thought it was that for the first 64 of my 65 years on the planet.
Reshpeck 2 meses atrás
You thought that in your very first years? I don't remember having any thoughts about how stereo sound was reproduced in a single groove of vinyl until I my third or fourth year at least.
Salim Musstta
Salim Musstta 2 meses atrás
@Reshpeck huh?
657BIueArmy 2 meses atrás
@Reshpeck I have to admit that my father was a Woolworth's record salesman, and all the talk in our house was of stereo separation and cross talk. It actually led to my parents divorcing, although they still spoke over each other.
gavin kemp
gavin kemp 2 meses atrás
I think it's in part because mechanical systems required working out everything from end to end and that to make it work you need to think of everything. With electronics and computers in particular, you are dealing with a lot of layers of abstractions in which each layer is relatively easy and changeable. This means the overall system is far more complex, but the bit you need to think about is much more simple. For example, if you are working on signal processing, you don't need to worry about how that signal is produced or even the quantum effect involved in processing that signal. You can simply assume that the layers of abstraction you are using will work as documented.
Reshpeck 2 meses atrás
@657BIueArmy Wow, those must have been intense disagreements over some very esoteric subjects
IHWKR 2 meses atrás
This is very apparent on vinyl in some Led Zeppelin songs like Whole Lotta Love and very much synonymous with Pink Floyd's sound engineering. Pro tip: if you need to clean your vinyl, use wood glue 😉
IdahoFox 2 meses atrás
Stereo recordings are a fascinating aspect of older tech. Where it also gets interesting is in how else multiple sound channels have been tried over the years. From the quad-channel records with actual encoding methods to the "binaural" records from the earlier years by making a record with either two spirals running beside each other or two completely separate mono tracks played together to get the stereo effect. But the 90-degree single track setup was certainly the most cost-effective for the average consumer who just wanted to listen to nice music.
Rambler Andy
Rambler Andy 2 meses atrás
BTW, did you ever do a video for 4-channel vinyl records or perhaps how the Hafler circuit audio output is achieved?
Clark Blumenstein
Clark Blumenstein 2 meses atrás
Yes!!!!! I know what I’m doing for the next however long this video is. Being into tube gear and vinyl and a speaker builder for 20+ years I ~ THINK ~ I understand the way a stylus works, but I’m sure I’m about to learn something new. Love your vids! You are one of the most cogent, easy to follow educators on youtube. Thanks for remembering the audio geeks :)
Griff Ruby
Griff Ruby Mês atrás
Next it would be nice to describe how the four channels were combined on a phonograph record during the quadraphonic days of the 1970's.
Enterim 2 meses atrás
There's a lot of interesting physical considerations for vinyl mixing/mastering. The bass frequencies have to be center-panned as the low frequencies create such big grooves that they can cause the needle to jump out if they're side-panned. Records undergo RIAA equalization where they're mastered with attenuated low-end freqs so the grooves can be physically smaller and denser on the record, and the attenuation is reversed on playback.
macronencer 2 meses atrás
Thanks! I didn't know about that attenuation trick. It's amazing how many clever ideas are used in this sort of technology. I'm also now wondering whether the record sent into space on the Voyager probe was a straightforward mono recording without any clever tricks. I'd assume so, or the aliens might have trouble reproducing the sound properly...
Lawrence D’Oliveiro
Lawrence D’Oliveiro 2 meses atrás
You say “interesting physical consideration”, I say “analog quality compromise”. Aren’t you glad all that has gone away with digital encoding?
Joel E
Joel E 2 meses atrás
There's something similar done in analog FM broadcasting. In the audio processor or stereo generator, a pre-emphasis curve (with either 50 or 75 microsecond time constant, depending on where you are in the world) is applied to the audio to improve the signal-to-noise ratio on higher frequencies. Then FM receivers apply the inverse of that curve, and it sounds normal.
Dan Petitpas
Dan Petitpas Mês atrás
@macronencer Those discs on the Voyager probes were RCA videodiscs and it came with a cartridge to play them.
macronencer Mês atrás
@Dan Petitpas Really? I can't find any mention of that. Both NASA and Wikipedia say they were "phonograph records" but they don't call them "videodiscs", although I know there are images encoded on them. I'm a bit confused now - do you have a link to any further info please?
JC Tecklenburg
JC Tecklenburg 2 meses atrás
As a visual creative professional, I'm used to using the difference blending mode on images but the fact that you can do the same with audio is blowing my mind
TravisTev 2 meses atrás
I once had an informal cassette copy of some instrumental music that somehow got recorded as a stereo-difference signal without realizing it. No idea how. But I always thought the music was supposed to sound like that. It was quite a surprise to finally hear the original stereo recording years later and hear instruments I didn't even know were there. It certainly sounded much better and crisper and explained why my old copy always seemed somewhat flat and lifeless in sound quality.
James Geary
James Geary 12 dias atrás
The same diagonal system is used in CoreXY 3D printer heads. One motor goes diagonal one way, the other goes diagonal the other way. Running both motors the same way is X movement, running them opposite is Y movement. Interesting to see how far back the idea goes.
royhills 2 meses atrás
I once had a vinyl album with two groves on one side, with a different track listing for the two grooves. It was "matching tie and handkerchief" by Monty python.
daniel b
daniel b 2 meses atrás
Applied Science (the channel) has a superb electron microscope clip/animation of stereo records and the needle moving along them, very relevent and shows exactly what is described.
JayTemple 2 meses atrás
I was surprised that the stereo effect bit worked. Not because you could pull it off; I just didn't think the speaker on a laptop would be that advanced.
Jessica Allen
Jessica Allen 2 meses atrás
Your videos are so rad! My boyfriend and I have been binge watching them all week. Your humor is delightful 😂❤
Rob Friedrich
Rob Friedrich Mês atrás
Early experiments tried also to use the right channel vertically and the left horizontally, but the idea with 45° is genius. The stereo plays also mono records, the bass is mono, but this is ok, we can't locate the low frequencies, the wave lengths are too long, we locate a bass instrument by the harmonics.
gc2009able 2 meses atrás
Continues to be one of my favourite channels to watch with subtitles! Love it.
Retro Tech
Retro Tech 2 meses atrás
The lateral movement can be described as the sum of the 2 channels and the vertical movement, their difference. If you had a cutter that cut vertical difference information (L-R) and lateral sum information (L+R) you would come out with a perfectly compatible stereo disc. Fairchild in fact made such a stereo cutting system in the mid 1960s. It also can be compared with “M/S” microphone techniques for stereo.
Mikko Rantalainen
Mikko Rantalainen 2 meses atrás
The important things about the encoding used to press stereo LPs is that the sideways movement has the highest bandwidth so it makes perfect sense to use that for the average signal between the channels. The same idea is used in digital audio compression, for example MP3 files support "joint stereo" encoding where one of the channels is encoded as delta to the main channel. Because real world stereo music typically has very similar audio on both channels, encoding one channel as difference to the another saves a lot of bandwidth.
Boomer Gaming
Boomer Gaming 2 meses atrás
That was pretty interesting, but now it calls for a follow-up. How was quadrophonic sound created and reproduced from albums? That sounds like an even more complicated venture.
Finn Bo Jørgensen
Finn Bo Jørgensen Mês atrás
I inherited from my grandma some Pathé records that used vertical engraving. They rotated at 90 rotations per minute and the track started close to the label and worked its way out to the edge. For the fun of it, I copied them to tape using the following setup: I set the speed to 45 Rpm and the tape recorder to half speed. Then I changed the polarity of one of the stereo channels on the pickup and set the recording to mono. This had the effect of recording the vertical movement instead of the normal horizontal mono movement. I also changed the stylus to a 78 model with wider tip. The sound was not good, but still quite acceptable. Unfortunately, I don't have these records anymore.
goandy89 25 dias atrás
I find it wonderful you explained the stereo imbalance channel as this is a trick used in some higher end car audio to provide a balance to the audio with a “center” speaker that is connected across the left and right speakers to only play the imbalance as a mono that is bilaterally perceived as an amplification of the opposite channel to even the listening experience with such short distances to the drivers. Generally done with a wide band tweeter. Ie the infinity audio in my 2004 dodge ram 1500. With a “9” speaker infinity audio system lol quite ingenious with driver stacking along with the use of 2ohm drivers.
Mujaki 2 meses atrás
First off, LOVE the extra descriptions of the stereo jazz in the Closed Captions. Second, it's interesting to contrast this to how stereo sound (and mono playback compatibility) was encoded in old analog television broadcasts. I believe it was a combined full mono track on the left channel, and stereo seperated right on the right channel?
kidwave1 2 meses atrás
The fact you added the bloopers was comical, ha. Thank you for the explanation. I had seen HOW records were pressed before, which is fascinating in itself, but I had never considered HOW the stereo signal is achieved.
Joey Colclough
Joey Colclough 2 meses atrás
I wanna hear how Quadrophonic records were made now
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