How MP3 Players Work
The MP3 player is the most recent in an evolution of music formats that have helped consumers enjoy their tunes. Records, eight-track tapes, cassette tapes and CDs-none of these earlier music formats provided the convenience and control that MP3 players give music lovers. With an MP3 in hand or pocket, a consumer can create personalized music lists and carry thousands of songs wherever they go.
All of that stored music and the MP3 player itself fit into a device about the size of a deck of cards. That's a big difference in size -- as opposed to carrying a CD player and CD storage case. These advantages propel the popularity of MP3 players. This popularity is also related to the wide variety of players available to consumers. MP3 players come in many different shapes and sizes as manufacturers try to appeal to wide audiences. You can even find players that are integrated with other devices and consumer products.
In this article, you will learn more about the technology inside MP3 players and the different types of players out there. You'll also find out where to get tunes and how you can accessorize your player.
The Technology
Unlike earlier forms of music players that required moving parts to read encoded data on a tape or CD, MP3 players use solid-state memory. An MP3 player is no more than a data storage device with an embedded software application that allow users to transfer MP3 files to the player. MP3 players also include utilities for copying music from CDs or Web sites and the ability to organize and create custom lists of songs in the order you want to hear them. This list of songs is called a playlist.
The MP3 player is the convergence of many technologies. Alone, none of its components are revolutionary, but together they create an unprecedented consumer product. In addition to storing music, the MP3 player must play music and allow the user to hear the songs played. To do this, the player:
Pulls the song from its memory
Decompresses the MP3 encoding
Runs the decompressed bytes through a digital-to-analog converter
Amplifies the analog signal allowing the song to be heard
The Inside Stuff
Specific components may vary, but here are the basic parts of a typical MP3 player:
Data port
Memory
Microprocessor
Digital signal processor (DSP)
DisplayPlayback controls
Audio port
Amplifier
Power supply
The player plugs into your computer's USB port, FireWire port or parallel port to transfer data. USB-based players transfer data many times faster than those that use the parallel port. The MP3 files are saved in the player's memory.
Memory types include:
With the exception of the last one, these are all types of solid-state memory. The advantage to solid-state memory is that there are no moving
parts. No moving parts mean better reliability and no skips in the music. MP3 players that contain tiny hard disk drives can store 10 to 150 times more than Flash memory devices can
The microprocessor is the brains of the player. It monitors user input through the playback controls, displays information about the current song on the LCD panel and sends directions to the DSP chip that tells it exactly how to process the audio.
The DSP pulls the song data from memory, applies any special effects, or EQ, and streams it to the amplifier. The DSP runs a decompression
algorithm that undoes the compression of the MP3 file and then a digital-to-analog converter turns the bytes back into sound waves. (See How Analog and Digital Recording Works for details.)
The amplifier boosts the strength of the signal and sends it to the audio port, where a pair of headphones is connected.
All of the portable MP3 players are battery-powered. Most use one or two AA batteries and last for approximately 10 to 12 hours on a single charge. Many of the players also have AC adapters so they can be plugged into a normal electrical outlet, and some even offer DC adapters for use in a car.
