The term “digital audio player” most commonly refers to “portable music players that use nonremovable, erasable digital media instead of removable media as a means for storing and playing digital music recordings” (Holmes 2006). It is a major transformation for the recording industry, since removable media had long been the standard method for recording sound, from the first tinfoil and cardboard cylinders of early phonographs, to shellac and vinyl resin long-play records, to coated magnetic tape and polycarbonate-covered aluminum film discs. While early digital music lived up to the music industry’s concern of piracy, recent years have seen an explosion of digital music use as computer software and audio compression formats have made music and digital audio players both extremely portable, and extremely fashionable.

A Brief Timeline of Audio Players

According to The Routledge Guide to Music Technology, the first device capable of recording sound signals was Léon Scott de Martinville’s 1857 invention called the “phonautograph.” His device could not, however, reproduce sound signals, but the idea was adapted by Emile Berliner into a disc music player he called the “gramophone.” Preceding Berliner’s 1887 invention, however, was Thomas Edison’s tinfoil cylinder phonograph, which made the first recording of the human voice in 1877. By 1878, Edison launched his Edison Speaking Phonography Company to produce recording and playback machines, which initially were intended as dictation machines for business purposes.

By 1891, however, Edison expanded into the entertainment field. For the next several years, material innovation improved both cylinder and disc machines, but disc-style gramophones and phonographs eventually won out. Berliner’s gramophone became especially marketable through the invention of the spring motor record player, as first used by Eldridge Johnson in a hand-cranked motorized gramophone for Berliner in 1896. Berliner and Johnson eventually joined interests to form the Victor Talking Machine Company in 1901. Their 1905 Victrola became the industry’s premiere disc phonograph, and the era of the 78 RPM disc standard was born (Holmes 2006).

By the 1920s, innovation in electrical recording and amplification systems combined with the advent of magnetic recording to help drive the recording industry for the next two centuries. In the 1940s, Columbia introduced the 33-1/3 RPM long-playing record (LP) at about the same time the Decca Record Company helped usher in the era of high fidelity with full frequency range recordings. Meanwhile, 3M introduced a “plastic-based recording tape with a magnetic oxide coating” as the Ampex Corporation led the way in high-quality tape recording machines (Holmes 2006). In 1963, Phillips introduced the audio cassette tape format that eventually became popular among home audio enthusiasts. Analog cassette systems displaced the 8-track, but other systems remained popular for high fidelity applications among professionals until the advent of digital recorders. LPs, incidentally, remained in high production through the 1980s and continue to be manufactured to the present day.

Sony developed the first digital audio recording devices to be used by professional studios in 1978. The next year, Sony revolutionized the world of personal audio with the introduction of the Walkman portable audio cassette player, initially called the “Soundabout.” Though compact disc technology emerged the following year, Sony went on to sell over 100 million Walkman-like audio players—and that was in addition to innumerable knock-offs by other manufacturers, even before personal audio players evolved to play digital mediums such as compact discs (1988) and minidiscs (1992). Later, the first commercially available digital audio players in the United States using the MP3 format (which had been in development since 1987) would launch the digital audio player revolution that achieved meteoric success with the introduction of Apple’s iPod in 2001 (Holmes 2006).

File Sharing Early in the Digital Music Age

Digital music is, in short, the binary “ones and zeros” version of its analog equivalent, and recording studios have used it for a number of years. Only in recent years, however, have recording studios allowed electronic distribution of media, though it is in part due to consumer-level technology that allowed people to begin dealing with digital music on their own. File sharing is extremely controversial, and it led to the restructuring of such notorious Internet file-sharing organizations as Napster, which was launched in 1999 and enjoyed immense success before being shut down for copyright infringement. Napster had been made possible by successful high-quality audio compression combining with inexpensive larger hard drives and faster downloading speeds . It was eventually relaunched using industry-approved licensing and distribution methods.

The immense popularity of file sharing, however offensive, had caught the attention of the industry for a couple of reasons. One the one hand, music piracy as well as other forms of electronic media piracy, was a long-standing and well-founded concern of the industry. This concern had led professionals to protect high-end technologies such as digital audio tape due to the fear that individuals would learn to “expertly steal material” (Holmes 2006). CDs—since they used uncompressed and, therefore, quite large, digital files—initially helped protect the original audio while still exploiting digital technology.

On the other hand, however, consumer’s increasing preference for digital audio led the industry to develop methods for proper handling of media that protected both the business and the artist. A primary reason for the ease of digital file sharing has to do with compression codecs (compression/decompression algorithms). Compression is the process by which files are made smaller through coding schemes that reproduce the original signal elements at playback (Holmes 2006). MP3 files, for example, are as much as 90 percent smaller than the original file, making sending and downloading much quicker.

Digital Music, Technically Speaking

The conversion from analog audio to digital files allows for the application of compression coding. In the history of audio recorders and players, computers allow users the greatest flexibility and interaction, especially once compression codecs evolved in availability and quality. Technically speaking, “an analog signal is a continuously variable waveform, while a digital signal is a numeric representation of that waveform… [made by] measur[ing] the waveform at many regular intervals (called ‘sampling’), and then stor[ing] these measurements as numbers” (Hart-Davis and Holmes 2001). Digital compression works by using psychoacoustic analysis of the analog audio stream and removing frequencies outside of the range of human hearing. By exploiting the limitations of human hearing, MP3 is example of a “lossy” method of compression: MP3 removes information, whether outside of the range of human hearing or by recognizing repeating patterns and eliminating the excess. Alternatively, “lossless” compression such as ZIP retains all the original information but “squashes” the source down.

Finally, sampling is based upon three kinds of measurements: sampling rate, precision, and bitrate. Sampling rate is the frequency of the sound analysis measured in thousands of cycles per second while sampling precision, or resolution, “is the amount of information about the individual sample that is saved to the audio file.” Bitrate measures the storage of encoded information in kilobits per second (kbps). Near-CD-quality sound exists in encoded MP3 files at about 128 kbps, and compression software is capable of sampling both higher and lower bitrates—though the higher the bitrate, the better the final sound (Hart-Davis and Holmes 2001).

The International Standards Organization (ISO) and the International Engineering Consortium (IEC) are largely responsible for overseeing the emergence of the MP3 format. Their Moving Pictures Experts Group (MPEG) systematized the MP3 encoding method, which was developed at the University of Erlangen in Nuremberg, Germany, under the direction of Dieter Seitzer (Tiemann 2006). A number of key patents for MP3 technology belong to The Fraunhofer Institut Integrierte Schaltungen (Integrated Circuits). Layer III, one of the major divisions of the MPEG-I class, includes most of the relevant MP3 audio encoding, so MPEG-I layer III got shorted in MP3 (though MPEG-2 contains some coding as well). It is a digital music format that compresses audio files to about a tenth of the size of the uncompressed original audio file, but without sacrificing much of the audio quality of the physical media containing either analogue or digital files (Hart-Davis and Holmes 2001).

Meanwhile, Apple’s Advanced Audio Coding (AAC) is a digital audio format—now improved and assigned within the MPEG-4 division—is the data compression scheme originally assigned to the MPEG-2 division in the mid 1990s. This semi-proprietary format is copyrighted and, though versions are used by other technologies, the audio format can be played only by the iTunes music system (Tiemann 2006). AAC files are said to have “more robust coding efficiency” in compression, which means a better reproduction of audio than MP3. According to MP3-tech.org, AAC handles more channels and higher frequencies than MP3, as well as improved usage of existing MP3 tools (Bouvigne 2003). Similarly, Windows Media Audio (WMA), the proprietary audio compression format of Microsoft, was designed as an improvement over MP3 and, as with AAC, provides Digital Rights Management (DRM), which is software providing for digital copyright protection (Holmes 2006).

In fact, Apple’s iTunes revolutionized the digital media industry through DRM software algorithms. The AAC format provided what MP3 could not: protection against rampant piracy. As a result, the record industry collaborated with iTunes and similar companies to create large catalogs of artists and songs available for legal purchase and download. Since 2001, iTunes has grown to provide millions of songs for preview that are relatively inexpensive to download (typically 99 cents a song) or entire albums that are often cheaper than a physical CD. (iTunes now also includes podcasts, music videos, movies, and other digital media for preview and download.) Artists have taken advantage of digital-audio formats to promote their work, both by releasing specific tracks or publishing and distributing entire albums online, reducing the cost of distribution. The file formats also allow artists a closer connection with their audience by encouraging instant feedback in online discussion forums or e-mail (Hart-Davis and Holmes 2001).

iPod's Domination of the Digital Audio Market

Since digital audio is here to stay, the digital audio player has become a virtually ubiquitous device among trendy music enthusiasts, especially as its increased portability allows people to use it everywhere from the home to the car to a hike in the mountains. Diamond Multimedia’s Rio PMP300 was the first such device to gain widespread attention in the United States, though it was preceded by Eiger Labs’s F10, both in 1998. These audio players, and similar devices from other manufacturers, became immensely popular, especially as Napster grew and more users logged in to share music.

At the turn of the millennium, audio players were already being integrated into PDAs and cell phones. But when legal issues temporarily shut down Napster, MP3 file sharing screeched to a halt, opening the door for Steve Jobs and Apple Computer to release their iPod. With the support of the music industry, Apple’s digital audio player and proprietary format quickly took over the digital audio market, leaving other companies from Microsoft to Sony scrambling to get a share. And while the iPod is not the only MP3 or digital audio player on the market, it is easily the  best known device and, for the time, still the most sought-after (Holmes 2006).

Interestingly, a large part of the success of the iPod and iTunes is attributable to the success of iTunes on the Windows platform. Macintosh users claim a relatively small share of the computer industry, so Apple’s decision to release a Windows version of iTunes in 2003 has helped iPod sales immensely, even though Windows continues to use and market players designed specifically for its WMA format. But then, trend watchers for the Discovery Channel suggested part of the success of the iPod must be attributed to the ear buds that came standard with every player: those tiny headphones bucked tradition and abandoned black in favor of white.

Suddenly, the iPod was not merely a legitimate, technologically advanced must-have device for taking an immense amount of tunes on the go—it was also a fashion statement that “helped turn the iPod from a tech gadget into a cultural icon” (Discovery Channel). And it is a statement embraced by well over 150 million people worldwide in just a few years. But fashion aside, while sales of the iPod have helped drive its evolution, it is Apple’s innovations that have allowed the iPod to continue to be a leader in the market.

The first-generation iPod premiered with its trademark rotating mechanical navigation wheel and up to 10 GB of hard drive space. The second generation added a touch-sensitive navigation wheel and doubled the storage capacity, a pattern seemingly consistent over the many subsequent generations. Meanwhile, Apple continually adds additional features—most prominently, color screens with video capabilities. The company has also added less-expensive, scaled-down versions to its lineup, including the iPod mini and the iPod shuffle (Tiemann 2006).

In 2007, Apple entered the cellular phone market with the iPhone, integrating all the features of the iPod with the modern cell phone, including a full range of multimedia applications, Internet browsing, and touch-screen technology. Meanwhile, other products such as the Microsoft Zune, as well as devices from Creative and SanDisk, directly model features on the iPod, but also work to advance both the MP3 and WMA formats by further enriching their sound quality through technology that better replicates the uncompressed original. These devices, however, claim only a small share of the digital audio player market.

Apple’s persistent innovations and innumerable other manufacturers' technological research and development mean it is anyone’s guess what the future holds for digital audio players. For now, however, it is worthwhile to look back at the relatively short 150-year history of audio players to see how far, technologically speaking, we’ve already advanced.

-- Posted August 4, 2008

References

Bouvigne, Gabriel. MP3’Tech. "MPEG-2/MPEG-4 – AAC." 1998-2003. Accessed: July 26, 2008.

Hart-Davis, Guy and Rhonda Holmes. 2001. MP3 Complete. San Francisco, CA: SYBEX, Inc.

Holmes, Thom, ed. 2006. The Routledge Guide to Music Technology. New York, NY: Routledge.

"iPod History." Discovery Channel. Jan 3, 2007. Accessed July 12, 2008.