Brains On! Science podcast for kids

How does music get recorded and stored?

31 min
Nov 25, 20255 months ago
Listen to Episode
Summary

This episode explains how sound is recorded and stored across different physical media formats. Through an imaginative shrinking adventure, hosts Molly and guest Canyon explore how microphones convert sound waves into electrical signals, how those signals are encoded onto CDs, cassette tapes, and vinyl records, and how speakers reverse the process to recreate sound.

Insights
  • Sound recording fundamentally relies on pattern preservation: the original sound wave pattern is converted into different codes (electrical, digital, magnetic, physical grooves) but the underlying pattern remains constant throughout the entire process
  • Microphones and speakers are mechanical inverses of each other—microphones convert air vibrations into electrical signals while speakers convert electrical signals back into air vibrations
  • Physical media storage methods (CDs, tapes, records) all work on the same principle of encoding audio patterns in different physical formats, making them functionally equivalent despite their different appearances
  • The technology for recording music has remained conceptually unchanged for 150 years, predating cars, radios, and light bulbs, demonstrating the durability of the core recording principle
  • Understanding how sound is encoded and decoded demystifies the relationship between digital files, physical media, and the listening experience
Trends
Educational podcasts for children are increasingly incorporating interactive storytelling and imaginative scenarios to explain complex scientific conceptsPhysical media formats (vinyl records, cassettes, CDs) continue to have cultural relevance and are being actively used by younger audiences alongside digital alternativesScience education content is shifting toward multi-sensory, narrative-driven explanations rather than traditional lecture formatsSubscription-based ad-free content models are becoming standard for independent educational podcasts targeting familiesLive event tours are being leveraged by educational podcast brands to build community and monetize beyond traditional advertising
Topics
Sound wave physics and vibration patternsMicrophone technology and diaphragm mechanicsSpeaker technology and audio reproductionCD storage and laser reading technologyCassette tape magnetic encodingVinyl record groove encodingAudio signal conversion and electrical encodingDigital audio file formatsRecording equipment and studio technologyPhysical media formats comparisonAudio pattern preservation across formatsEardrum mechanics and hearingMusic storage history and evolutionAudio cable signal transmissionComputer-based audio recording
People
Molly Bloom
Primary host of the episode guiding the educational narrative and shrinking adventure through recording technology
Canyon
Guest co-host from Montreal, Canada whose question about recording music on CDs, tapes, and records inspired the episode
Mark
Co-host who participates in the shrinking adventure and explains recording equipment mechanics
Sandin
Co-host who manages the poodle heavy metal band recording scenario and directs the shrinking vehicle
Rachel Breeze
Sound designer credited for the episode's audio production
Carla Moran
Teacher who uses Brains On episodes in science classes and provided feedback on educational effectiveness
Quotes
"Sound waves are just a pattern of waves that push and pull on air. Some waves are big, and some are small. Some are short and fast, and some are long and slow. All of those things make the waves of air sound different to your ear."
MarkMid-episode explanation
"It's all about keeping the same pattern. You see, sound waves are just a pattern of waves that push and pull on air...Microphones just take that same pattern and write it as electrical pulses."
MarkRecording explanation
"Sound is just patterns of wiggling air. When you record music, it goes into a microphone through a cable. Into a machine where it is recorded. Then you can put the music on a CD, a cassette tape, or a vinyl record."
MollyEpisode summary
"Think of the inside of a microphone like a machine version of your eardrum. It's listening to music, except in your ear, your brain turns the wiggles of air into a message for your brain and your brain interprets that message as sound."
MarkMicrophone mechanics explanation
Full Transcript
Hi friends, you might have heard that Bark, Sandin and I are on the road this spring with brains on live. We've been to several cities so far and it has been so much fun. Our next two stops are Atlanta and Fort Lauderdale. That's at the end of March. Then we just announced that we added Lawrence, Kansas in May and Columbus, Ohio in June. We're also heading to Chattanooga, Durham, Milwaukee, Portland, Buffalo and Ann Arbor, Michigan. We hope you'll be able to join us at one of those shows. We can't wait to see you to get tickets and get more information. You can head to brainson.org slash events. That's brainson.org slash events. Brains on Universe. You're listening to Brains On. We're serious about being curious. Hey friends, ever wonder how you're hearing me right now? I mean, it's not like there's a tiny Molly hidden in your speaker telling you stuff. That would be weird. Very. But how is sound like music or podcast recorded and played back? We're going to surf a sound wave to find out. Plus, we'll find out how microphones and speakers work and meet a robot who has eaten several decades worth of music. It'll make sense. In a minute. Trust me. So keep listening to Tiny Molly. I mean, this podcast. This is Brains On from the Brains On Universe. I'm Molly Bloom and today my co-host is Canyon from Montreal, Canada. Hi there, Canyon. Hi Molly. You know, Brains On is a rare thing these days. A show made for kids and with kids and people all over the world tune in to hear answers to the questions they send in. We're also supported by people just like you who subscribe to our SmartyPass. When you subscribe, you get ad-free episodes, bonus content, live virtual hangs with Molly, Mark and Sandin and more. Go to SmartyPass.org to sign up and make sure the show lives on. Thanks. So Canyon, this whole episode is inspired by a question that you sent to us. Yeah, I asked how do they get music into CDs, tapes and records? An excellent question. Do you listen to music on all those devices? Yeah, my mom has a record player at my house and sometimes I listen to CDs in the car, but I don't really listen to tapes. Okay, so which kind of music would you say you listen to the most? Like which way of listening? I usually listen to records the most, but CDs, I would say it's just sometimes I listen to CDs. So when you listen to records, do you use the record player yourself? No, it's usually my mom who just puts the record on and then starts it. Then you rock out together? Most of the times. Nice. So are you a headphone or a speaker person? Like how do you listen? I would say I actually both. Awesome. So there are lots of ways to listen to music. Like Canyon said, he listens to records, CDs and on his tablet. But in case anyone isn't familiar with CDs, cassette tapes and records, these are all examples of physical media. Media is stuff like movies, music and art and physical means you can hold it. It's not just something that lives on the internet or on your phone. Here to tell us more about CDs and tapes and records is Robot Who Only Eats Physical Media. Take it away, robot. Thank you, Molly Bot. Um, always not a robot. Not a robot? Then why is her head covered in coils? They're adorable curls. Curls, coils, potato, potato. Anyway, yes it is I, robot who only eats physical media. Why do I only eat physical media? Because digital files give me robot gas. Excuse moi. Now I adore eating CDs. They are shiny flat discs about five inches wide like a bagel. They have a hole in the middle also like a bagel. And they play about 70 minutes of music again like a bagel. Mmm, this hoodie in the Blowfish CD is divine. But Mr. Robot, bagels don't play music. What? Then why do you eat them? Um, because they're delicious food. Meh, tomato, tomato. I don't think you're using that saying correctly. Why would I? I don't understand human foods like potatoes or tomatoes or pinky toes. My food is robot food. And the only robot food I'm interested in is physical media, remember? Kind of hard to forget when your name is robot who only eats physical media. Now cassette tapes are a whole different snack. They are small plastic rectangles about the size of a deck of cards. Inside the cassette there is a spool of brownish ribbon. Kind of like a really thin roll of tape but not sticky. It's on that ribbon that the music is stored. Oh my, so delicious. Do you want a bite? It's Madonna's Immaculate Collection on Cassette. No thanks. I'm good. Ack, the brownish ribbon stuck in my teeth. Ah, there. Got it out. Any hoodle. Moving on, we have vinyl records or LPs or as I call them, dinner. These are large black flat discs about the size of a pizza. But unlike pizza, they are delicious. Actually, pizza is widely considered to be one of the world's tastiest foods. But it's covered in cheese and tomatoes. Now if you squint your robot eyes, you'll see that records are covered in tiny grooves. These grooves spiral from the outer edge of the record to the middle of it. Believe it or not, it is in these grooves and these little teeny bumpy lines. That is where the music is stored. It's also where the flavor is stored. Mmm, Miles Davis, you've done it again. Another perfect meal. Now if you'll excuse me, dining on physical media is best enjoyed when it's like Harry Styles' career after One Direction, solo. Ta ta! So CDs, cassettes, and records may be different shapes and sizes, but they're all just different ways to store music so you can play it back later. So, Canyon, what songs have you been obsessed with lately? I feel like I've been listening mostly just random AJR songs. Random AJR songs? Wonderful. My house has been obsessed with K-pop Demon Hunter soundtrack. I've been listening to that a lot, a lot, a lot. So when you're listening to AJR songs, what do you usually do while you're listening? I will usually play with my Lego, but with the right temperature, the right day, and like there's no snow outside. I will bring my iPad outside, I'll bring some headphones, and I will play with my soccer ball while listening to my music. Oh, that sounds very pleasant. The ability to record and store sound has been around a long time. Like around 150 years, which makes recorded music older than cars? Home radios, and light bulbs. But the way music is recorded is pretty much the same as it was back then. Someone plays music, the sound goes into a microphone, and it gets sent to some kind of recording device that saves it so you can play it later. More on that in a second, but as long as we're talking about playing sounds, let's play the... Mystery sound. All right, Canyon, are you ready for the mystery sound? Yes. Okay, here it is. What do you think? I think it's like a trailer being like hooked up to a car or a truck of some sort. A trailer being hooked up to a car or truck, that's a really good guess. Should we hear it one more time? Okay, any new thoughts? When I hear that, I feel like it's a machine of some sort or my last answer. Yeah, I like your guess of hooking up a truck or trailer. It sounded definitely like metal to me. I'm going to guess, because I have no idea what it is either, that it is a big metal pan and someone is putting it on a grate over a campfire? I don't think that's right, but I'm just putting it out there. You know, it's okay to be wrong. We are going to hear the answer at the end of the show. So stick around. Hey friends, we've got an episode coming up all about skunks. They're cute, they're cuddly, and they can stink. But the stink is a defense mechanism. That means it's a way for skunks to scare away animals that might hurt them, which is a pretty unique way to scare off your enemies. So we wondered if you could design a unique way to scare off animal enemies, what would it be? What about you, Canyon? What would your odd animal defense be? An animal chore chart. Tell me more, describe. Um, a lot of chores to do and something that either would get you wet to like do something that you don't want to do. I love that. The animals would stay away because they're like chores, a chore chart. No thank you and they'd run away. Ugh, I love that idea. Very, very clever listeners. Share your ideas for a wild animal defense mechanism by going to brainson.org slash contact. While you're there, you can also send us your drawings and questions. That's brainson.org and keep listening. You're listening to brainson. That's Molly and I'm Canyon. And we're talking about how music is recorded and played. So when you record music, it's the same. Hold on a sec. Hey, Mark and Sandin, do you have to make all this racket while we're taping? Oh hey, Molly. Perfect timing. I'm helping Sandin record the new band he's managing. New band? You know what, everyone's always saying I love heavy metal, but I wish there were more poodles in it. Oh yeah. Yes. Uh-huh. That's definitely something I've said. Well, this is the world's first all poodle heavy metal band. Meet Penelope and the poodles. Wow, Penelope can shred the guitar. And I didn't know dogs could hold drumsticks like that. Shhh, Molly, don't say xtay. xtay? You mean stick? No, uh, leave it. Bosco, leave it. Leave it. No, no, no, we're not playing fetch. That's for Tina's drums. The poodles are easily distracted. But hey, I figured since you and Canyon were learning all about music, we could help. I got the atom here and it's ready to go. Oh sweet, the atom, which stands for amazing truck of minimization. Yep, our shrinking vehicle. Hop in and the atom will shrink us down so we can follow a song as it gets recorded and stored. Yay, I was hoping I'd get shrunk today. Otherwise this shirt I wore would make no sense. You mean the shirt that says yay, I got shrunk today? Yep, wearing it when you don't have plans to shrink is a bit of a gamble, but sure paid off today. All right, let's get Minnie and take a spinny. Just give me a second to calibrate the micro-ingions and... There. Sandin's gonna stay behind and direct the band. Okay, Penelope and the poodles ready to rock? No, no, I said rock, not walk. Get back to your instrument, scope up. Good dogs, good dogs. Okay, now sit, stay, slay. Okay, Molly and Canyon, hold on. Shrink move activated. I love this part. Why is my underwear shrinking faster than the rest of me? Tight. Whoa, we're micro-sized. It sounds different from down here. Yeah, we're so small now we can surf a sound wave. Sound waves are how sound travels. When Bosco strums her guitar, the air around the guitar strings vibrate or wiggle. And the way it vibrates is the wave's pattern. The wave travels from the guitar strings to our eardrum and makes our eardrum wiggle, or vibrate, in the very same pattern. And then our brains take that vibrating pattern in the eardrum and translate it into sounds that we hear. So those rushing sounds and those are sound waves? Or waves of air? Exactly. That's the sound from Penelope and the poodles rockin' out. Now, when you're recording music, you need microphones to record those waves of air. Like that microphone there. Cool. The waves of sound are carrying us toward the microphone. We're heading straight to it. We'll be smashed to pieces. Don't worry. There are tiny holes in the microphone and we'll be fine if I can steer just right. There. Now we're inside the microphone. Doggy, that was close. I need a minute to settle my nerves. Understandable. Let's all take a breather while I go check on the microsity meters. BRB? Cool. Seems like a good time to check the mailbag. Yeah. We get a ton of email and actual paper mail from you all. And since we've been moving headquarters, it's really piled up. Sandin's been going through it piece by piece. So let's check in with him. Time for the mailbag. I love all this mail. Okay, let's see. Oh, I'm going to open this letter. Ooh, it's a drawing of Gungadore. Looks perfect. Okay, let's see. Oh, I'm going to open this email. Ooh, it's a bill. Wait, that's not fun. I'm just going to forward that one to Molly. Ah, let's see. Oh, check it out. We got a message from a teacher. Let's give it a listen. Hi, my name is Carla Moran. I'm a third grade teacher in Canton, Michigan. I love to use the brains on podcast with my science classes. I match up episodes with science units like life cycles and traits. For the traits unit, one of my favorite episodes is Meet Sandy, the left-handed mutant snail. It's something that kids can relate to being right or left-handed. As a science teacher, I like that it features school kids as scientists. In the episode, it's a student who discovers a sinister snail. My students love the voices of the snail and the sound effects. And the fact that it also talks about mutants. As a science teacher, I love all the questions that brains on ask and it gets kids to think about science and be interested in science. Oh, I love to hear it. Thanks for sharing us with your class. I'm sending you a free SmartyPass subscription. Enjoy. If you use brains on in your class, let us know about it. Oh, check it out. Another email from Molly. Let's see what it says. Sandin, stop fording me the bills for all the snake food you keep buying. You don't even have a snake signed Molly. Fair point. I don't have a snake yet, but when I do, it'll eat well. Okay, well, send us your drawings, life questions, or designs for a new room at brains on HQ. Just go to brainson.org slash contact. Bye. Quick reminder, if you don't want ads, but do want fun hangouts with me and the gang, join SmartyPass. Ad free episodes, bonus stuff, virtual hangs and more. Just go to smartypass.org. Now back to the show. Brain's on. This is brains on. I'm Molly. I'm Canyon. And I'm Mark. Molly, Canyon, and I are in our incredible shrinking truck called the Atom. We've shrunk down and we're inside a microphone. Now every microphone has something inside it that sound waves can run into. And if you look just ahead right over there, you'll see that this one has a tiny little plate. It's called a diaphragm. Whoa, neat. The waves of air are making that diaphragm plate thing vibrate and wiggle in a pattern too. Is that like how the sound waves of air make our eardrums wiggle? Yes, yes, exactly. Think of the inside of a microphone like a machine version of your eardrum. It's listening to music, except in your ear, your brain turns the wiggles of air into a message for your brain and your brain interprets that message as sound. In the microphone, that wiggling plate turns the airwaves into an electric signal. And that signal is sent through a microphone cable to a machine where it's stored. Wait, we're heading right towards the vibrating plate. Does that mean the microphone is going to turn us into an electrical signal too? Oh no, we'll be fine. I think. Or we might get turned into a pure form of energy that can either be contained or measured. Oh, that's bad. Why did I wear these socks that say, Yikes, I got turned into a pure form of energy that can either be contained or measured. Where do you shop for clothes, Molly? Hold on to your seats, people. Here we go! I can't believe it. I mean, despite not knowing what I was doing, we're totally fine. And I can't believe I wore underwear that says, despite not knowing what I am doing, I am totally fine. To be fair, all of my underwear says that, despite not knowing what I'm doing, I am totally fine. It's kind of my life motto. Wow, I can't believe what I'm seeing. Mark, what am I seeing? Oh, that's the electrical current inside the microphone cable. The sound waves from before have now turned into patterns of electricity. It's wild to me that sound can be turned into electricity. I know. It's all about keeping the same pattern. You see, sound waves are just a pattern of waves that push and pull on air. Some waves are big, and some are small. Some are short and fast, and some are long and slow. All of those things make the waves of air sound different to your ear. Microphones just take that same pattern and write it as electrical pulses. So the pattern was like a code, the same information, but stored in a different way. Yes, yes, yes, yes, yes. Exactly like code. All through the process of recording and playing music, that pattern from the waves of air is turned into different codes. Sometimes it's electric code. Sometimes it's digital code. But it's always the same pattern. And guess what? We're here! Technically, wherever you are is here, Mark. Can you be more specific? Good one, Molly. But we're in the recording equipment. It's the place where the sound from the microphone is stored so you can use it later. Oh, cool. So the sound is another code now? What kind of code is it this time? Well, in the olden days, you might churn those electrical signals from the microphone into a code on a special kind of audio tape. These days, the electrical signals are usually churned into a code that computers read. So we're in a computer right now? You betcha. That's amazing. What are the odds? Let me guess. You have a hat or anchorchief or something that says, wow, I'm in a computer? No, I just think it's amazing we are in a computer. But note to self to make that hanky my next crafting project. And you? After all the music is recorded and saved here, then it can be churned into an audio file. Huh, and I'll bet that master file has the same pattern as the original sound wave, but just in a different code. So the music went from sound waves in the air into a microphone where it became electrical signals, then it traveled through a cable to a recording machine. From there, it can be put onto a CD or tape or whatever. Perfecto correcto. Now, let's unshrink and get out of here before some antivirus software in the computer finds us and tries to delete us. Yikes. Wow. Why is my underwear not unshrinking fast enough? So tired again. Good to be me sized again. For sure. So Mark, after the music is made into a master file, how does it get on different things like tapes or CDs or records? Well, there are special machines that take the code from the audio file and turn it into yet another code. And that is put on the physical media. Tapes, records, and CDs, they all store that pattern, but just in different ways. That's right. And here to tell us more is me, Robot who only eats physical media. Thank you, Molly Canyon and Third Human, whose name I don't know. It's Mark. Unimportant. What is important is that I enjoy eating physical media, like a CD. Now, you can't feel it with your robot tongue, but inside a CD is a thin aluminum disc. And the pattern or code for the music is written on that disc. When you play a CD, it spins and a little laser reads that code and turns it back into an electrical signal. Like the one the microphone made? Yep, exactly like that Canyon. But this time that electrical signal is sent to a speaker. Speakers take the electrical codes. And turn them back in to sound waves. How do they do it? Inside a speaker, there's another kind of plate, like the one we saw on the microphone. The electrical signals make it wiggle in that same pattern as the original sound. And as it wiggles, it pushes on the air around it, creating sound waves. So a speaker is just a fancy way to turn that electrical signal back into a wiggling wave of air that you can hear. Ding ding ding, exactly. Yes, now back to me. CDs store their code on aluminum discs. Cassettes store it on that spool of tape inside the cassette. This time it is a magnetic code. Magnetic, nom nom, nom delicious. And again, a tape player reads the magnetic code on the tape and turns it back into an electrical code. Which is sent to a speaker. And turned back into a sound wave. I get it now. And finally, we have records. Like this limited edition version of Taylor Swift's reputation. Here, the music's code is stored as little bumps inside those tiny grooves. A very small needle rides on those grooves as the record spins. The needle helps turn that code back into an electrical signal, which goes to a speaker and you know the rest. The important part is that you thoroughly chew your records so you don't choke on look what you made me to. Taylor's version really does taste better. Hey guys, did you get the recording of the poodles? Sure did, buddy. And it sounds great. Combining poodles and metal was a truly inspired idea. Ugh, totally. By the way, has anyone seen my tape CD and record collection? They aren't in my tape CD and record bin. Oh, and look at what the time is. I have to go for reasons completely unrelated to what he just said. Bye. Sound is just patterns of wiggling air. When you record music, it goes into a microphone through a cable. Into a machine where it is recorded. Then you can put the music on a CD, a cassette tape, or a vinyl record. When you play music, it goes into a speaker. The speaker wiggles the air to make sound waves. Then your ears hear those sound waves and that's how you hear music. That's it for this episode of Brains On. This episode was written by Sanon Toddon. It was edited by me Molly Bloom, sound designed by Rachel Breeze, and mixed by Mark Sanchez. He also wrote our theme music, special thanks to Anna Winters, Steven Winters, and Blake Iverson. Many thanks to Ken Teporsky and Code of the North for all their website help. Brains On is an independent podcast. Our show depends on your support. Help the show grow by going to BrainsOn.org and sign up for SmartyPass. That's our ad-free feed where you get discounts on merch and live events. Plus hangs with Sandin, Merck, and me. Get good stuff for supporting good podcasts. Totally. Sign up today at BrainsOn.org. Now, before we go, let's take one more pass at that mystery sound. What do you think? Last time you thought maybe a trailer getting hooked up. Some kind of machine. I thought something with like a pan. I don't think that's right anymore. What do you think? Any new thoughts? I feel like I'm gonna stick with my thought. Your trailer thought? I think it's a good one. I think it's the inside of a pinball machine and someone is fixing it. All right, let's hear the answer. Hello, my name is Sophie from Arlington, Massachusetts, and the sound that you just heard was me opening and closing the flu of my fireplace. Oh, the flu of a fireplace. Can you hear that now that we know? It was metal, so we were both a tiny bit, right? Have you, do you have a fireplace? I used to. Yes, the flu is something inside the fireplace. Like I think that's the air in and out, I think. Oh, that was a tricky one. They stumped us. Now it's time for the brain's honor roll. These are the incredible kids who keep the show going with their questions, ideas, mystery sounds, drawings, and high fives. Sam from Guelph, Ontario, Eli from Delaware, Vera from Herndon, Virginia, Jack and Noah from Mercer Island, Washington, Alice and Elijah from Robinsdale, Minnesota, Dax from Portland, Oregon, Archie from Carmel, California, Emmett from Waynesboro, Virginia, Ila from Wyoming, Lucy from New Plymouth, New Zealand, Bethany from the UK, Hunter from Kin, Australia, Luca and Wyatt from Pennsylvania, Fiona from St. Louis, Walter from Great Falls, Montana, Ivy from Cincinnati, Miles and Dylan from Taipei, Taiwan, Anderson from Leipzig, Germany, Avery and Andrew from Knoxville, Tennessee, Keon from Bloomington, Indiana, Brooke from Apollo Beach, Florida, Amelia from Litchfield, New Hampshire, Shane and Kevin from Marlton, New Jersey, Montgomery from Vineyard Haven, Massachusetts, Finn from Altoona, Pennsylvania, Eddie, Rocky, Ray, Lou and Daphne from Austin, Texas, Jacob from Plantation, Florida, Donovan from Mesa, Arizona, Addie and Elise from St. Louis, Riley from Los Angeles, Paloma and Martina from San Jose, California, Karim from Manchester, United Kingdom, Edith from Kansas City, Edda from Merve, Freesboro, Tennessee, Bonnie from White Horse, UConn, Eleanor from Lake Oswego, Oregon, Stella from Salt Lake City, Abby and Grace from Elm Grove, Wisconsin, Caroline from Caseville, Utah, Alphie from Hitchin, United Kingdom, Hugo from St. Louis, Alex from Mucletoe, Washington, Adeline and Karina from San Francisco, Joanna from Shanghai, China, Francesca from Madrid, Juana and Serene from Dubai, Ashweenie from Dallas, Fort Worth, Lila from Stevenville, Maryland, Mia from Chilliwack, British Columbia, Jack from New Hampshire, Alistair from Halifax, Nova Scotia, Anthony Wesleyan, Richard from North Carolina, Jordan from Colorado, Richard from North Oak, Virginia, Allyn from San Francisco, Theo from Port Macquarie, Australia, Isabella, Isaac and Max from Basil, Switzerland, Logan from Bakersfield, Florida, Camilla from Longwood, Florida, Juniper and Porter from Newport, Washington, and McKenna from Flemington, New Jersey. Tune in next week for more answers to your questions. And thanks for listening.