A
digital audio player, sometimes referred to as an
MP3 player, is a
consumer electronic device that has the primary function of storing, organizing and playing
audio files. Some DAPs are also referred to as
portable media players as they have image-viewing and/or video-playing support.
History
The immediate predecessor in the market place of the digital audio player was the portable
CD player, or "portable audio device."
Kane Kramer designed one of the earliest digital audio players, which he called the IXI. His 1979 prototype was capable of approximately 3.5 minutes of audio playback but it did not enter commercial production. His UK patent application was not filed until 1981, patent 2115996 issued in 1985, and in 1987.
Apple Inc. hired Kramer as a consultant and presented his work as an example of
prior art in the field of digital audio players during their litigation with
Burst.com almost two decades later.
One of the chips making it possible to create portable MP3 players before market for mass produced devices took of was the Micronas MAS3507D
ASIC MP3 Decoder chip.
[ 091117 xilinx.com] Several electronics
DIY projects used this circuit. As a software based approach would have limited battery time severely. This chip allowed the
microcontroller to read data from a flash memory and feed the decoder chip, creating a low power solution.
The world's first mass-produced hardware MP3 player was created in 1997 by
Saehan Information Systems, which domestically sold its “MPMan” player in the middle of 1998. The South Korean company then licensed the players to Eiger Labs which distributed them—now branded as
Eiger Labs MPMan F10—to the North American market during the summer of 1998. The flash-based players were available in 32 MB storage capacity.
The
Rio PMP300 from
Diamond Multimedia was introduced in September 1998, a few months after the MPMan. It was a success during the holiday season, with sales exceeding expectations. Interest and investment in digital music were subsequently spurred from it. Because of the player's notoriety as the target of a major lawsuit
, the Rio is erroneously assumed to be the first DAP.
In 1998,
Compaq developed the first
hard drive based DAP using a 2.5" laptop drive. It was licensed to
HanGo Electronics (now known as Remote Solution), which first sold the PJB-100 (
Personal Jukebox) in 1999. The player had an initial capacity of 4.8 GB, with an advertised capacity of 1200 songs.
In 2000,
Creative released the 6GB hard drive based
Creative NOMAD Jukebox. The name borrowed the
jukebox metaphor popularised by
Remote Solution and also used by
Archos. Later players in the Creative NOMAD range used
microdrives rather than laptop drives.
In October 2001,
Apple Computer (now known as Apple Inc.) unveiled the
first generation iPod, a 5 GB hard drive based DAP with a 1.8"
Toshiba drive. With the development of a spartan
user interface and a smaller form factor, the iPod was initially popular within the
Macintosh community. In July 2002, Apple introduced the second generation update to the iPod. It was compatible with
Windows computers through
Musicmatch Jukebox. The iPod series, which grew to include
microdrive and flash-based players, has become the market leader in DAPs.
In 2002,
Archos released the first "portable media player" (PMP), the
Archos Jukebox Multimedia. Manufacturers have since implemented abilities to view images and play videos into their devices.
In 2003 the first MP3 players were installed into mobile phones in South Korea and the first artist to sell songs as MP3 file downloads directly to mobile phones was
Ricky Martin. The innovation spread rapidly and by 2005, more than half of all music sold in South Korea was sold directly to mobile phones. The idea spread across the globe and by 2005 all five major handset makers, Nokia, Motorola, Samsung, LG and SonyEricsson had released musicphones. By 2006, more MP3 players were sold in musicphones than all stand-alone MP3 players put together. The rapid rise of the musicphone was quoted by Apple as a primary reason for developing the iPhone. In 2007, the installed base of musicphones passed the 1 billion level, and today more than half of all mobile phones in the world have an MP3 player.
Although
online music services such as
RealNetworks’
Rhapsody also offer legal downloads through a subscription plan, the launch of the
iTunes Store in 2003 established the model of selling individual songs and albums for purchase.
Operation
Digital sampling is used to convert an audio wave to a sequence of binary numbers that can be stored in a digital format, such as
MP3. Common features of all MP3 players are a memory storage device, such as
flash memory or a miniature
hard disk drive, an
embedded processor, and an audio
codec microchip to convert the compressed file into an analogue sound signal.
Most DAPs are powered by
rechargeable batteries, some of which are not user-replaceable. They have a 3.5 mm stereo jack; music can be listened to with
earbuds or
headphones, or played via an external amplifier.
Types
Close-up view of the Philips GoGear SA1110 flash-based player
An MP3 CD player (
Philips Expanium)
Digital audio players are generally categorized by storage media:
- Flash-based Players: These are non-mechanical solid state devices that hold digital audio files on internal flash memory or removable flash media called memory cards. Due to technological advancements in flash memory, these originally low-storage devices are now available commercially ranging up to 64 GB. Because they are solid state and do not have moving parts they require less battery power and may be more resilient to hazards such as dropping or fragmentation than hard disk-based players. Basic MP3 player functions are commonly integrated into USB flash drives.
- Hard drive-based Players or Digital Jukeboxes: Devices that read digital audio files from a hard disk drive (HDD). These players have higher capacities currently ranging up to 250 GB. At typical encoding rates, this means that tens of thousands of songs can be stored on one player.
- MP3 CD Players: Portable CD players that can decode and play MP3 audio files stored on CDs.
- Networked audio players: Players that connect via (WiFi) network to receive and play audio.
Recording
Many players have a built-in
electret microphone which allows recording. Usually recording quality is poor, suitable for speech but not music.
There are also professional-quality recorders suitable for high-quality music recording with external microphones, at prices starting at a few hundred dollars.
Radio
Some DAPs have
FM radio tuners built in.
Common audio formats
Most audio formats use
lossy compression, to produce as small as possible a file compatible with the desired sound quality. There is a
trade-off between size and sound quality of lossily compressed files; most formats allow different combinations—e.g., MP3 files may use between 32 (worst) and 320 (best) kilobits per second. Different lossy formats may give files of different sizes for the same perceived quality.
The formats supported by a particular DAP depend upon its
firmware; sometimes a firmware update adds more formats. To listen to a file on a player, it must be in a supported format; format conversion on a
computer is usually possible, but with loss of quality.
MP3 is the dominant format, and is almost universally supported. It is a proprietary format; manufacturers must pay a small royalty to be allowed to support it.
The main proprietary alternative formats are
AAC and
WMA. Unlike MP3, these formats support
DRM restrictions that are often enforced by files from paid download services.
Open source formats, which do not require manufacturers or music distributors to pay a fee, are available, though less widely supported. Examples include
Ogg Vorbis,
FLAC, and
Speex.
Most players can also play uncompressed
PCM in a container such as
WAV or
AIFF.
Controversy
Although these issues aren't usually controversial within digital audio players, they are matters of continuing controversy and litigation, including but not limited to content distribution and protection, and
digital rights management (DRM).
Lawsuit with RIAA
The
Recording Industry Association of America (RIAA) filed a lawsuit in late 1998 against
Diamond Multimedia for its
Rio players,
[ alleging that the device encouraged copying music illegally. But Diamond won a legal victory on the shoulders of the Sony Corp. v. Universal City Studios case and DAPs were legally ruled as electronic devices.]Risk of hearing damage
According to SCENIHR, the risk of hearing damage from digital audio players depends on both sound level and listening time. The listening habits of most users are unlikely to cause hearing loss, but some people are putting their hearing at risk, because they set the volume control very high or listen to music at high levels for many hours per day. Such listening habits may result in temporary or permanent hearing loss, tinnitus, and difficulties understanding speech in noisy environments. See also
