Everything Everywhere Daily: History, Science, Geography & More - A Brief History of Digital Audio

Episode Date: November 6, 2023

Right now, you are listening to the sound of my voice on some sort of digital audio device. In fact, almost all of the audio you consume today was digitally recorded or edited at some point in the process. But sound is inherently analog. How does sound, the movement of air, become converted into 1s and 0s?  …and once sound is digitally converted, how is it distributed, and how has the digitization of sound changed the business of music and audio? Learn more about digital audio, how it works,, and how it changed how we consume audio on this episode of Everything Everywhere Daily. Sponsors BetterHelp Visit BetterHelp.com/everywhere today to get 10% off your first month ButcherBox ButcherBox is offering our listeners turkey FREE in your first box plus $20 off your first order. Sign up at butcherbox.com/daily and use code DAILY Subscribe to the podcast!  https://link.chtbl.com/EverythingEverywhere?sid=ShowNotes -------------------------------- Executive Producer: Charles Daniel Associate Producers: Peter Bennett & Cameron Kieffer   Become a supporter on Patreon: https://www.patreon.com/everythingeverywhere Update your podcast app at newpodcastapps.com Discord Server: https://discord.gg/UkRUJFh Instagram: https://www.instagram.com/everythingeverywhere/ Facebook Group: https://www.facebook.com/groups/everythingeverywheredaily Twitter: https://twitter.com/everywheretrip Website: https://everything-everywhere.com/ Learn more about your ad choices. Visit megaphone.fm/adchoices

Right now, you're listening to the sound of my voice on some digital audio device. In fact, almost all of the audio you consume today was digitally recorded or edited at some point in the process. But sound is inherently analog. How does sound, the movement of air, become converted into ones and zeros? And once sound is digitally converted, how is it distributed? And how is the digitization of sound changed the business of music and audio? Learn more about digital audio, how it works and how it changed how we consume audio, on this episode of Everything Everywhere Daily.

What if your perceptions about the past were wrong? ThruLine is a podcast that takes you back in time to uncover the parts of the story that may have gone unnoticed. It effectively turned day into night. And how it shaped the world now. Time travel with us every week on the ThruLine podcast from NPR. Pretty much all audio recorded nowadays is digital, or has been digitized in some form.

Even if you purchase a vinyl record, the playback mechanism might be analog, but the original chording and mixing was probably done digitally. The words you're listening to right now were digitally recorded and edited, and you are listening to it on some sort of digital device, most probably a smartphone. So how does digital audio work?

We first have to start with the basics of what sound is. Sound is air pressure in the form of waves. You've probably seen a graphical representation, representation of a sound wave before. It's a pattern of up and down lines that are in a sinusoid pattern. The key thing to understand about sound waves and the thing that defines what anything analog is, is that they're continuous. If something is continuous, it means that there are no gaps. Imagine drawing a line on a piece of paper with a pen. At every point in the line, there's ink. There are no gaps between any two points in the line. If something is not continuous, then it's

considered to be discrete. Unlike something continuous, something discrete can be broken down into a finite number of steps, values, or objects. Now imagine, instead of drawing a line on a piece of paper, you instead drew a series of very small dots in the form of a line. There would now be gaps between the points, making it discrete. However, if you drew enough dots that were very small and very close together, it would appear to be a continuous line. This distinction between continuity and discreetness is the difference between analog and digital. So how then do you convert something analog and continuous into something discrete and digital? The answer has something to do with the example I gave above of drawing a line.

If you can draw a discrete line with enough points, then it will appear to an observer as a continuous line. So now, let's go back to our sound wave. If we could capture a continuous sound wave and draw it on a piece of paper, how could we turn this into something discrete and digital? If we put the wave on the horizontal x-axis of a graph, we could approximate the shape of the wave by making rectangles from the x-axis to the point on the wave. Depending on how many rectangles we use, it might look rather blocky,

but it would get the overall shape. However, if we use smaller and smaller rectangles, it would eventually look like a very smooth continuous curve. The process of turning something analog into something digital is known as sampling. Surprisingly, sampling actually goes back well before the age of computing. It was first proposed to be done mechanically to put multiple telegraph transmissions on a single line, a technique known as multiplexing. In the 1920s, the technique was developed called pulse code modulation.

Pulse code modulation is basically a way to actually do what I just described. It takes pulses of an analog signal and measures each pulse so that the wave can be broken apart and turned digital. The first systems were designed for facsimile systems that could send simple images over telegraph and telephone lines. In 1937, pulse code modulation was used for the first time on voice signals by a British engineer named Alec Reeves. Even though he received patents for his invention, there was no real practical use for it at the time. Eventually, computers arose, and the applications for pulse code modulation with computers became obvious as computers could easily handle discrete digital information. However, computers initially were only involved in the transmission of signals, not the recording of digital audio signals.

In 1967, Japan's national broadcasting company, NHK, developed a 30-k-harts 12-bit device that could encode an audio signal digitally and store it on videotape. And now I should explain exactly what those numbers mean, 30 kilohertz and 12 bit. Every time there is a pulse in a pulse code modulation, a measurement is taken. The number of bits is basically the number of different possibilities for each measurement. This is known as bit depth. For example, if there are eight bits, each measurement can have one of 256 possible values. This is sort of like how many colors an individual pixel can have on a computer screen.

At 16 bits, there are 65,536 values. And at 32 bits, it can have 4,294,967,296 distinct different levels. 30 kHz simply measures the number of pulses that are made. So in this case of the NHK system, there were 30,000 pulses measured every second. And this is known as the sample rate. So the system built by NHK in 1967 sampled a sound wave 30,000 times a second and saved each sample as a number with 12 ones and zeros.

Both the bit depth and the sample rate go into determining the amount of data recorded and hence the quality of the audio. While digital audio recording was possible as early as 1967, there was a big problem. All of that sampling took a lot of computational power and all that data required what was at the time an enormous amount of storage.

Digital audio simply wasn't practical given the computing power at the time. However, thanks to Moore's law, the price of computing kept dropping dramatically, and by the late 1970s, the first commercial digital recordings were created and released. Sony and 3M created prototype digital recording systems

and released the first commercial pulse code modulation systems. However, the real revolution in digital audio was unveiled on March 8, 1979, when the Phillips Corporation unveiled the prototype of their compact disc player. The first prototype CD was a recording of Vivaldi's The Four Seasons. In July that year, Warner Brothers released the first a digitally recorded record Bob Till You Drop by guitarist Rye Kuder. The compact disc, hereby just known as the CD,

wasn't the creation of one company. It was primarily a joint effort between Phillips and Sony, who were both working on similar laser-based digital audio systems. If they had come out with competing systems, it would have been another VHS Beta Max fiasco, and digital audio may have been still born. In the creation of a standard, they had to agree on several things, including the bit depth and sampling rate. What they eventually agreed upon was a sample rate of 44.1 kilohertz and a bit depth of 16 bits on each stereo channel. The sample rate wasn't arbitrarily chosen. Sound is in waves, so it has a frequency.

The limits of human hearing go from approximately 20 hertz to 20 kilohertz. Now there's a thing known as the Nyquist rate, which states that for the accurate reconstruction of an analog waveform, you have to sample the wave at a rate twice that of the highest frequency of sound. So, 44.1 kilohertz was selected as a sample rate, because it is more than twice that of the highest frequency any human. can reasonably hear. So the highest sound frequency that a CD can play is 22.05 kilohertz. This was relatively easy to decide because it was based on a natural human limit. Sony originally wanted 44.1 kilohertz and Phillips wanted just 44 kilohertz.

But there was a great deal of debate about bit depth. Phillips wanted 14 bits and Sony wanted 16. In the end, Sony won out as they had the higher quality proposal for both bit depth and sound depth bit depth and sample rate. They also eventually decided on a disc that was 120 millimeters in diameter that could hold 74 minutes of music. Phillips initially wanted a 115mm disc, but Sony insisted on a 120 millimeter disc, supposedly so it could hold the 1951 recording of Wilhelm Fert vongler conducting Beethoven's Ninth Symphony at the Beyrite Festival. That story has been declared apocryphal by some, but others who worked at Sony at the time said it was true,

but it had nothing to do with Beethoven. It really had to do with the fact that Phillips had a plant ready to go to produce 115mm discs and Sony did not. By forcing the larger disc, it required Phillips to retool its plant, giving Sony time to catch up. The longer play of CDs also gave it a significant advantage over vinyl long play records, which could only hold 22 minutes of music per side. The CD was introduced to the world in 1981 and the first discs were commercially available in October 1982. Compact discs exploded, and by 1987, for the first time, digital music sales surpassed vinyl analog sales. Despite other digital music formats that were released, such as digital tape and CD singles, the 120mm CD was by far the most popular

digital format for music. The average CD could store about 700 to 800 megabytes. That might not seem like much today, but 25 years ago, that was a lot. Personal computers and the internet began to expand in the 1990s, and people began copying CDs to their computer hard drives. In the late 90s, computers usually had hard drives that measured in the low gigabytes. A single CD could take up a large amount of space on a hard drive. And the reason why CDs took up so much space is because the data was uncompressed. The solution to the storage problem was compressing the data. In particular, the solution was an algorithm developed in Germany known as MPEG 1 Audio Layer 3, or as it became better known, MP3. MP3 could shrink the size of an audio file by a factor of 5 to 10, the amount of

compression being determined by how complex the sound file was. With smaller MP3 files, it became possible to transfer music even on slow dial-up internet connections. Because digital files can be shared without loss of the original file, the sharing of digital music became rampant. In 1999, a service was launched that organized this sharing called Napster. Napster, for a short time, revolutionized music, and it didn't make the music companies happy. It allowed for peer-to-peer sharing of MP3 files. Anyone could share music with anyone else. And so it came as no surprise that Napster was shut down in 2001. However, Napster was hardly the end of digital. music and the internet. At about the same time Napster shut down, Apple released the iPod.

The iPod wasn't the first MP3 player, but it popularized digital music that didn't require a disc. This opened up the door to direct digital music sales and eventually to all-you-can-listen digital music streaming services. One of the largest players in music streaming, Spotify, was launched in 2006. Of course, digital audio wasn't just about music. It allowed anyone to record audio and distribute it globally with close to zero cost. As early as 2000, I was doing streaming from my desktop computer on a program called Winamp. I'd stream commentary playing EverQuest as well as play music. And at that time, I was also part of an online streaming show called All Game Radio

that had hundreds of people listening simultaneously. And this was all before the launch of podcasting in 2003, the history of which I have covered in a previous episode. I'd like to conclude with one thing that has caused a lot of controversy over the years. Is analog sound superior to digital? There are some audio files who insist that analog recordings are superior to digital. They will often say it sounds warmer, whatever that means. This is a subject that has been tested to death, and obviously there are many factors that go into the quality of a recording.

However, time and time again, it has been found that people, cannot tell the difference between digital and analog sound, especially at high sample rates and bit depth. Even self-proclaimed audio files can't tell the difference any better than flipping a coin. The fact is, if the sampling is high enough, whatever difference that exists is beyond the capability for humans to notice. While there has been a small resurgence in vinyl records, most of the reason for the Renaissance has to do with the physical aspect of owning a record, not necessarily the sound. The quality, affordability, and ease of use will ensure that digital audio is going to be with us for a very long time. The executive producer of Everything Everywhere Daily is Charles Daniel.

The associate producers are Peter Bennett and Cameron Kiefer. Today's review comes from listener, The One and Only Smarty Pants over on Apple Podcasts in the United States. They write, fencing. Have you ever considered doing an episode on fencing in the history of it? Great podcast. Thanks, smarty pants. I think fencing would be a great topic for a podcast. After all, fences and fence building, a.k.a. fencing have played an important role in history. Actually, now that I think about it,

I could also do an episode on selling stolen goods and competitive sword fighting. Remember, if you leave a review or send me a boostagram, you two can have it read on the show.