How do vinyl records work?
I can't believe these things exist. Also, hi new subscribers!
Happy Saturday, Amateurs!
I’m writing to you from Friday evening, where it’s -3 outside and only one of the radiators in this apartment works, and it’s not the one in the living room. It’s not the one in the bedroom, either. So a hot kitchen it is. Actually, it’s a warm single shelf where I keep my cookbooks.
Could be worse. Michelle and I can hold them for warmth and get some reading in while we’re at it. (It’s actually fine, we’re duvet-on-the-couch people and I just bought a new sweater to replace the one I cut the sleeves off of. You know, for fashion or whatever. I do what I want.)
In other news, it feels pretty cool to be featured at #15 (last I checked) on the Substack Science list! A big, huge, monumental thanks to you, specifically, for making this thing possible. Welcome to the group of new subscribers from the past while as well! Every one of you mean the world to me and I hope you have as much fun reading this newsletter as I do writing it.
For good measure, I’ll re-introduce myself. My name is Nat and I’m beaming this publication into your devices from Vancouver. My background is in…a lot of things that are not science.
I have a BA in Legal Studies and History from the University of Waterloo. After that, I went on to almost go to law school (decided not to), almost get a master’s degree (got halfway then stopped), and kind of pursue a writing career (adult education classes for a term and then my next set of classes were cancelled). I worked at a meat market and a hardware store (separately), as a teaching assistant, and as a cheesemonger. Since 2017, I’ve been out here on the west coast having the time of my life. You know, living, laughing, loving, etc.
Eleven months ago I left my retail management job to get back to what I love to do, which is writing. What better time to change careers than…this. Hah, that’s a story for a different time. It’s actually been a wonderful, fulfilling challenge that produced all kinds of cool opportunities. I’ve been covering Major League Baseball over at Gusata since April. Since September I’ve copyedited about 3 million words [sweating.gif] with a marketing agency. I’ve also written some pretty cool websites and this year I’m finally getting my book underway in a matter of days. Not bad for a patchwork year, right?
Plus, this newsletter has been a fixture since I started it back in August on, to be honest, kind of a whim! I’ve always felt like science has been a part of my life, or at least something I’ve thought a lot about. Things like the weight of the earth and how a song can get stuck in someone’s head for days on end. Being curious about things I don’t know very much about is more of a state of being than anything else. I can remember, in particular, and having a penchant for going on hours-long Google deep dives about who knows what what I should have been studying for something more important.
I might not have a background in science, but I think there’s something special about having fresh eyes for concepts that shed light about the sort of normal, marginally weird stuff about the world. There’s actually a lot of fun to be had doing the digesting of the information. That is, doing the usual heavy research and turning it into something that non-science people might find amusing or interesting.
My philosophy about science communication is that half the battle in getting people interested about the world around them is making the information accessible. I don’t think Bill Nye or Raven the Science Maven would reach as many people as they do if they were just really, really good at science. They’re getting play outside of science circles because they’re excellent communicators.
So as much as having a science background is important to the understanding of science, there’s still lots for us non-science people to enjoy thanks to people who can act as a bridge. I hope I can be that for you.
This newsletter is free if you want it to be, but I do write it as part of my workweek. Paid subscriptions are the reason I can regularly block off time from my other clients and still pay the bills, so you can imagine the thrill they bring me! If that’s not in the cards, sharing posts with someone new works great, too.
Let’s get to it! This week: the incomprehensible magic of vinyl records.
Vinyl records have made a huge comeback. For the first time since 1986, they’re outselling CDs in North America in a time when physical music is struggling to compete with streaming services. Vinyl is a favourite of modern music connoisseurs for its rich, textured sound quality. It’s one of the few types of technology that hasn’t changed much since its inception, outside of the manufacturing process.
Back in the 1870s, Thomas Edison figured out a way to record sound.
He eventually designed a device he called the phonograph that had a brass cylinder wrapped in tinfoil, which rotated and moved lengthwise when turned by a hand crank. On one side was a diaphragm, or very thin membrane, connected to a needle. When sound waves were forced into the receiving end, it caused the membrane to vibrate and the needle to etch a groove into the foil as the cylinder was being turned by the crank, thus recording sound. A second needle and an amplifier were on the other side. When the cylinder was set to the beginning and the needle placed in the grooves, the original sound was reproduced as the vibrations were amplified.
Edison created his first voice recording by shouting the words to "Mary had a little lamb" into a mouthpiece, causing the sound waves to vibrate a needle and etch the nursery rhyme into tinfoil for playback.
It’s still the way it works! In case it’s buried in that pull quote, this is the ultimate gobsmack: when the needle carves the sound into the foil, it’s in the actual pattern of the sound waves that are vibrating it.
The tinfoil approach wasn’t very hardy and the recordings were typically only good for a couple of plays after the initial etching. Their short-lived nature didn’t work well for mass-producing consumer copies for regular play. Major upgrades to the technology in 1887, 1901, 1906, and finally in the 1940s allowed most households to access recorded music via turntables and longer-lasting lacquered records.
Now the process for pressing vinyl is pretty different. It actually take four separate etching and pressing processes to produce a record.
First, the studio perfects the master recording and gets it ready for production. A thick disc-shaped object called a lacquer goes onto the cutting machine and it works just like the tinfoil cylinder back in the day. Signals come down through a cutting stylus and it etches the master recording into the lacquer in a spiral from the outside to the inside, just like you’d play a record at home. The lacquer is the master mould from which all other records of that recording are made.
Step two is where the lacquer gets coated in a softish metal, often nickel or silver, to make a metal master copy. If you’re still with me, the metal master is a cast of the lacquer, so it’s got the inverse pattern on it. Ridges, not grooves.
One more metal record copy later and that copy is called the mother. It’s used as the stamper, which is basically the negative version of the original recording (again). It’s the mother that stamps all the consumer records, thanks to a hydraulic press that squashes it down into soft, steamed vinyl like a sandwich. A splash of cool water later and the record is born! Again!
Don’t ask me why so many copies are involved because I have no idea.
For a modern vinyl record to make a sound, a bunch of things have to happen.
First, the record spins thanks to a rotating rubber turntable it rests on. The stylus, made of a tiny conical diamond at the end of a metal strip, then swings out and over top. The arm serves as the connection between the grooves and the amplifier.
A record's groove – and there is generally just one that spirals gently to the centre of the disc – is tiny, usually around 0.04-0.08mm wide (depending on the level of the signal). If you were to unravel it, the groove on a 12-inch LP would extend to a length of about 500 metres.
The two sides of the groove sit at right-angles to each other, with the point of that angle facing down. Each side of the groove carries what can only be described as wiggles that represent the right- and left-channel audio information.
The side closest to the outside edge of the record carries the right-channel signal. This information can be stored in an area as small as a micron (one-thousandth of a millimetre), so the scale of the task to retrieve it is immense.
This also explains the sensitivity of record players to external vibrations and other disturbances.
As the record turns runs and the stylus rides the spiral around the grooves, the 3D inscribed sound waves vibrate the stylus in the reverse of how they were etched. The vibrations travel upward through the arm and into a cartridge in its little case thingy. This is where the magic happens.
The vibrations go into the cartridge come out the other end as electrical signals, which can then be adjusted for proper listening levels and sent out into the world as sound. The clever thing here is the way the translating works - the vibrations impact the energy given off by the copper coil, which then changes how the magnet interprets the magnetism. It’s those wavelengths that enter the amplifier and become sound.
I know it’s science but…it still feels like magic.
Fundamentally, records are still spinning plastic discs with the actual soundwave-shaped grooves etched into them. A diamond (????) dragged over top somehow makes music. They shouldn’t work, but they do.
That’s it for now - I’ve got some records that could use a spin.
Until next time, friends!