How Do Portable CD Players Work?

It is amazing when you think of storing music on a shiny, round piece of plastic and insert it into a portable device (a portable CD player) to listen to music wherever you go. Although portable CD players have been in existence for more than 3 decades, they are still one of the most popular ways of playing and listening to music on the go.

Have you ever wondered how your portable CD work or how it actually reads the CD you inserted into it and convert it into an audible sound? Let’s take a closer look.

Characteristics of a Portable CD Player

The major characteristics of a portable CD player include;

  • Stop button: the stop button enables the user to be able to stop a track at any desired point, and it allows the user to switch tracks easily
  • Play/pause button: this button enables the user to pause the track in the middle, and once the user pushes the play button again, the track resumes from the same place the listener left it.
  • The fast-forward button: this button enables the user to be able to fast forward the track for as long as the user holds down the button.
  • The rewind button: it allows the user to be able to rewind the track for as long as the user presses the button down.
  • The liquid crystal display screen: this shows a display of how much a battery is left, the exact track currently playing, the time elapsed or the number of time the track will take.

Benefits of a portable CD player

Better sound quality

The most important thing to consider is the quality of the sound. When an MP3 player is used, the compression from the mp3 files removes some information from the digital sound so as to reduce its size. In the process, more than 90% of the database from an original recording is thrown away.

Meanwhile, there is a difference between the quality of the sound obtained from an MP3 file and the traditional uncompressed CD recording.


A portable CD player can be very small in size, depending on its version, and the creativity of its brand or manufacturer as technology becomes better each day. A portable CD player can be as small as a CD, thus, giving you the benefit of being able to carry it about easily and listen to your favorite tracks.

One of the benefits of a portable CD player is that it is easy to store. Since they are small in size, they do not occupy much space in your home.

Customizable playlist

Another benefit of a portable CD player is that you can select the track you wish to listen to or simply customize your playlist which is impossible with a cassette or record player. The player can quickly move its laser to any part of the disc and can even program the number of the tracks to be played; this allows you flip from one track to the other.

Reduced loading time

Another good advantage is that it doesn’t waste the time of loading when you want to listen to a song in the player. With a portable CD player, the time to download music file which usually takes several hours to download, no longer take longer than a few minutes

Different sharing files in the media

With a portable CD player, all files could be transferred easily through either physical means, such as; CDs, USB or the online means. You can also use the MP3 files with players such as; Quick Time, Winamp, Windows Media Player, etc.

It doesn’t require another device to convert all music files

With a portable CD player, the boring tasks of having to change the platform between a device and all files can be avoided since the player enables you to download and save all your audios directly to your CD player.

How Does Portable CD Player Work?

To fully understand how a portable CD work, you have to understand the brain behind the CD being played. Portable CD players use the optical technology and do not rely on magnetic or mechanical technology unlike the vinyl plates or the magnetic tape. The major problems encountered by cassettes and LPs is the physical contact of the player with the tape or record being played which ware them out gradually.

CD players avoid this with the use of a round shiny plastic (CD) and laser lights to record, read or play the information stored on it. Theoretically, a CD should never wear out since the only thing that touches its surface is a harmless beam of light from the laser. CDs are coated with an aluminum layer (that helps to reflect the laser light) and covered with lacquer and protective polycarbonate along with the label that is printed on it.

That is why you must keep your CDs properly to avoid scratching the surface which will end up affecting the reflection of the laser beam, and hence yields poor or skipping sounds.

Information is stored on a CD in a digital (numerical) form. When music is recorded, it under a process called “sampling” where the sound is measured and converted into a long string of binary numbers (a pattern of ones and zeros) and stored in this format. This means that your CD contains no music, but a very long list of numbers. It contains “land” (flat unburned area) and “pits” (etched bumps on the CD surface).

When storing information on the disc (also known as burning CD), the laser cut some bumps (pits) into the disc surface and leaves some part flat and unburned (known as land). A land represents one while a bump signifies zero, and stored on the disc. This information is held in a tight and tiny continuous spiral space that would reach about 6km when stretched in a straight line so, you cannot see it with your eyes, but can only be read by the optical device of your portable CD player.

The Operation of Portable CD Player

Inside your portable CD player, you would find a small laser known as semiconductor diode laser; you will also find a miniature photo-electric cell known as a light detector. When you insert the disc or push the play button, the electric motor (on which the disc is mounted) powers up and rolls the disc at a speed of about 500 rotations per minute.

The semiconductor diode laser then switches the laser beam on, and it scans along the tracks on the disc that is inserted into the player, with the photo-electric cell, from the middle of the disc to the outside.

Then, the motor gradually slows down while the laser with the photo-electric cell scans the disc from the middle to the outside as the number of the track increases.

Similarly, the surface of the disc moves faster past the laser beam and the photo-electric cell, as the distance from the middle of the CD increases; so more information will be read within the same period of time.

The laser light (which is red in color) is thrown to the shiny side of the disc, it then reflects off the pattern of “bumps and the lands” on the flat area of the disc. The laser light is instantly being reflected by the lands while the pits disperse the light.

The photocell detects and realizes it has seen a land whenever the light reflects back, it then sends electric currents to an electronic circuit which reads and records the number “1.”  The electronic circuit reads and records the number “0” when the photo-electric cell does not record anything since the light does not reflect back.

The electronic circuit and scanning laser gradually reproduce the binary numbers (pattern of 0 and 1) that were initially stored on the disc from the factory. These binary numbers are decoded by another electronic circuit (DAC or digital to analog converter) in the portable CD player, and then convert them into a dynamic pattern of electric currents. The output (earbuds or headphones) converts the electric current to sound, so you can now hear the sounds.


This article has shown you how a portable CD player works. Now that you understand it’s working principle, you can clear all the misconceptions you have on how CD and CD player work. I hope you found this article educative and informative? If yes, feel free to share.

Audio Loli