Mp3s have embedded themselves into daily musical life so thoroughly that they're taken for granted. They don't call attention to themselves as aesthetic objects like records; instead, we interact with them as files, documents, icons. They're infinitely duplicable and available in seemingly infinite numbers. At the same time, however, mp3s are intensely controversial. More than a decade after the government took down Napster, these digital objects remain at the center of intense debates about morality and musical value; they've eradicated the scarcity of music recordings, doing away with more than a century of economic and social realities about how, when, and where music can be accessed. And, if you listen to certain types of music or talk to certain people about them, mp3s sound quite horrible.

In his new book, Mp3: The Meaning of a Format, McGill University professor Jonathan Sterne exhaustively and eloquently traces the history of the mp3 from the initial hearing model developed in Bell Labs to the current debates about piracy. As the author argues, each time we rip a CD to our hard drives, we're not only saving space in our living rooms or ensuring we have the appropriate gym soundtrack, but also reaffirming a fundamental idea about the limits of human perception.

"With an mp3, you're not going to have the same enjoyment that vinyl collectors talk about in terms of physicality, though, for a lot of people, that pleasure has been transferred to computer electronics."

Pitchfork: People often describe mp3s as "dematerialized" or "invisible" music. You argue that they're actually "things" comparable with CDs, though.

JS: They're just different kinds of things. You can hold an mp3 in your hand, you just need some kind of container for it; Apple developed an entire campaign about the thousands of songs you can hold in your hand. There's a materiality to them because you run out of space on your hard drive, or you can or can't stream them depending on bandwidth. But the important thing is that their materiality comes with completely different affordances than something like a CD.

With an mp3, you're obviously not going to have the same enjoyment that vinyl collectors talk about in terms of the physicality of the medium. Although for a lot of people, that pleasure has been directly transferred to computer electronics. The whole fashionable-portable-audio-player phenomena is very much of a piece with the enjoyment of records, except that it's not a subcultural phenomenon, and certainly doesn't lend itself to the same kind of aestheticism that comes with being a record collector. But the flipside, in a way, is that mp3s are closer to what I would call the social demand for music-- the desire to be with music, to move with it and share it. They're much closer to that than a record is.

Pitchfork: One of the book's best chapters is about the tests audio engineers ran in 1990 and 1991 to determine the standard for quality.

JS: Actually, the story of music testing comes from a longer history of industrial testing called hedonics, which I trace back to World War II. Hedonics was developed as a part of industrial psychology to try to measure and test pleasure and displeasure. For instance, if you're packing string beans in cans for G.I.s, how disgusting do they have to be before people won't eat them? Or on the flip side, a company like Frito Lay has chip testers at the ends of their production lines. The question isn't, "How tasty is this potato chip?" But: "How does the taste of this potato chip compare with the standard potato chip?"

This was the mode of testing that was used with the mp3. So the first question is, "What's the difference between one of several possible new coding schemes and CD-quality audio?" It's always relative to other audio. Really, it's just different flavors of processing, which is the defining characteristic of contemporary music aesthetics. So much stuff we hear now is so heavily processed. If you heard an unprocessed voice in a music recording, you would think it was wrong, because it didn't have dynamic range compression, it isn't heavily edited, there isn't any artificial reverberation added. It would sound strange to most listeners.

The MPEG listening tests used a variety of recordings: some castanets, a Suzanne Vega or Tracy Chapman tune, Ornette Coleman, a solo bass guitar piece, examples of male and female speech. The testers would listen to each of these recordings, flip back and forth between different coding schemes and the original recording without knowing which was which, trying to determine the difference. They'd do it over and over for hours-- the process is quite exhausting and unpleasant. If a tester was correct more often than they would be if they were guessing, the researchers would know there was a perceivable difference.

The question that immediately arises is: Would you get different results with different music and with different listeners? In the case of the MPEG test listeners, we're talking about professional engineers, people who work for audio companies, or people who work for radio stations. If you look at the aesthetics of the recordings, they all conform to this sanctioned radio aesthetic in terms of how recordings are made and what they sound like. I wasn't able to hear all the recordings, but if you listen to the commercial stuff, everything's recorded in exactly the way you'd expect an engineer at a radio station in 1991 to classify as "well-recorded." There isn't anything too esoteric or strange.

So by choosing mainstream music as the tests for MPEG audio, they actually produced a format that doesn't conform to universals of human hearing, but does conform very well to the record industry. In other words, a small number of mastering engineers have determined what good recordings will sound like.

Pitchfork: In the popular history of mp3s, Suzanne Vega's a cappella version of "Tom's Diner" is situated as the key musical moment in the engineering of the format. But you dispute the validity of that argument.

JS: The Vega recording is super interesting because if you listen to the recording in headphones or at a high volume on good speakers, you can hear a massive echo in the background at certain points, especially at the ending of phrases. In the first verse, listen for the sound after "dinner," "corner," "argue," "somebody," and "in." That's because she's singing very close to the mic and they're using a lot of dynamic range compression. That goes with the aesthetics of the time. So even this a cappella recording that's talked about as "pure" and "natural" and "organic" is this highly processed artifact, and the referent of perceptually coded audio is not Suzanne Vega singing in a room, but Suzanne Vega singing on a very well produced record.

Pitchfork: A lot of people cite piracy as the reason why mp3s became the ubiquitous medium for 21st-century music. But you broaden that out and consider some other factors that contributed to the format's ubiquity.

JS: Absolutely. Obviously, filesharing and unauthorized copying is a factor-- when I say "piracy," I really mean unauthorized copying, because piracy is not a real thing. In fact, it's a crazy term because it combines people in their rooms downloading music with armed thieves in boats off the coast of eastern Africa. So really we're talking about an industry that wants to limit copying as much as possible and control the means of purchase, use, and recirculation in problematic ways.

The mp3 took off after an Australian hacker cracked a piece of encoding software that the Fraunhofer Institute, which owns a lot of the patents for the mp3, created. It gets re-released for free, and people start using the software to rip mp3s from their CDs. Within a year or two, because they're so common, companies like Microsoft and Apple are signing deals with Fraunhofer, and by the time Napster takes off, anyone with a computer could use software to rip a CD to mp3.

That's part of the story, but there's a much more important part. When we think about music piracy or unauthorized copying, we normally think about it in terms of a record industry and an end user. But I actually think there's a more important relationship involving the conduit industries, which are as much media industries as the recording industry. These people benefit tremendously from file sharing. My favorite example of this comes from 2001, when Sony Music (the record label) joins a suit against Napster put forward by the Recording Industry Association of America at the same time Sony (the consumer electronics manufacturer) releases a CD player that can play mp3s. Where do you think those mp3s come from? You could say the same thing for the initial iPod.

Maybe now that the iTunes store is old enough, there are people in the world who have bought everything natively digital and didn't rip or download anything. But for a very long time in the 2000s, the ISPs, people selling hard drives, people selling bandwidth, people selling music playback gadgets, and even people selling new computers all benefitted greatly from file sharing. They had a huge economic interest in it. This is a big debate in Silicon Valley; the Free Culture movement. Content provision is something that helps amplify search engines, ISPs, and other companies that depend on people going out and finding content to make money.

"Music piracy is not a real thing. In fact, it's a crazy term because it combines people in their rooms downloading music with armed thieves in boats off the coast of eastern Africa."

Pitchfork: What do you see as the future of the mp3, if not, as you say in your book, the end of the mp3?

JS: Well, I think it's going to be around for a while, because people have very large music collections in mp3 format that they may or may not have bought. And if they didn't buy them, are they then going to spend a lot of money to replace them the way baby boomers did with CDs and LPs? It's a much tougher sell.

There are competitors to the mp3, some of which are open source like .ogg, which is a great alternative because it is completely open, but it also means that content industries like Apple are quite hostile to it because they see it as an indirect threat. Mp3s are with us as long as we're using computers and the same kinds of music platforms we're using today. When the next telecommunications infrastructure comes along-- with new devices and new ways of engaging with music-- that's when the dominance of the mp3 and compressed audio in general will be challenged.