11-28-2006 08:35 PM
Most home CD players are contained in a plastic casing, which also houses the electrical system and the user interface. The plastic casing can be manufactured in many colors and textures and the overall shape may be square or rectangular, with sharp or rounded corners, or a mixture of both.
CD players designed for car audio systems or computers generally have a front casing and exposed sides and back, as these parts will be covered by the car or computer. The front casing is generally flat and, like other CD players, available in a variety of colors and textures.
The housing of a portable CD player will also contain ports used to connect the player to a powered or unpowered speaker, headphones and/or a power system (see electrical wiring in the United States or in the UK). A portable CD player generally contains an internal power source in the form of batteries.
The housing of a stand-alone CD player contains speakers and perhaps a radio and/or tape deck. CD players used in component audio systems contain a power source, the user interface, and numerous ports to connect the player to the various parts of an audio system.
A CD player has three major components: a drive motor, a lens system, and a tracking mechanism. The drive motor rotates the disc between 200 and 500 revolutions per minute. The tracking mechanism moves the lens system along the spiral tracks in which information is encoded, and the lens reads the information using a laser beam. The laser reads information by focusing a beam on the CD, which is reflected back to sensor. The sensor detects changes in the beam, and interprets these changes to read the data. This data is output as sound using a digital-to-analog converter (DAC).
A subcode in an audio CD contains information on the total number of audio tracks, the running time on the CD, running time of each track, and other information. This information allows the drive motor to speed up or slow down as needed to read data at a constant rate.
The user interface of a CD player can vary widely from manufacturer to manufacturer. However, some common components are various buttons, knobs, and a display device. Common buttons include play, pause, stop, advance/fast forward, back/rewind, and in the case of a multiple-CD player, CD selection. Knobs allow control of volume, balance, and, if the player includes a radio tuner, radio station. The screen can contain a wide variety of information, but common data are track number and track time, and in the case of multiple-CD changers, CD number.
Nobody uses a CD player anymore. Talk of the old media format in this thread.