Inside an MP3 Player
We’ve certainly come a long way from Thomas Edison’s mechanical phonograph cylinder that reproduced sound when played on a phonograph, passing through paper music rolls played on a pianola, gramophone discs, LP vinyl records, audio cassettes of high-quality polyester, and plastic CD discs read by a laser. Today’s MP3 trumps all of the previous storage and playback devices, both in quality and bulk. An MP3 player which stores and plays music can be as small as a sugar cube.
MP3 is shortcut for MPEG Audio Layer III. It is a digital audio encoding format used for consumer audio storage, as well as a standard for the compression of audio for transfer and playback on digital audio players. MPEG, in turn, stands for Moving Picture Experts Group. It is this group that designates standards for video and audio compression and transmission.
All MP3 players consist of three basic components –memory, microprocessor, and power source.
The memory consists of specialized solid state chips. With no moving parts, wear and tear is virtually eliminated. Audio stored in the chips are first compressed thus allowing them to accommodate a bigger number of songs. A compression ratio of 10:1 is the standard for audio compression. To illustrate, a four-minute song that is uncompressed normally requires 40 MB of space on a standard CD. With MP3 compression, this can be reduced to 4 MB. A 1 GB MP3 player can hold as many songs as 20 CDs can store.
MP3 players incorporate a microprocessor that senses electrical impulses from the command buttons on the player’s control panel. Acting on these commands, it retrieves the specified file stored in the memory chips, decompresses it, and converts it to sound waves. These waves are sent to the audio port where the external speakers are attached. MP3 player microprocessors also include programs that allow you to manage your music files, and to copy or move files to and from a computer.
Sources of power for MP3 are almost invariably miniaturized rechargeable batteries. Indeed, without miniature batteries, it is highly likely that MP3 players may not have become as popular as they are, as one important source of their appeal is their portability.
Some MP3 players have both audio and video capabilities, but the basic components remain the same for all of them.