Over the last few years the way we listen to music has changed drastically. Large collections of records, tapes or even CDs are now a thing of the past. The format of choice nowadays is mp3. The development of mp3 technology has allowed huge music collections to be contained on a tiny device which fits comfortably into the pocket. Have you ever asked yourself how do mp3 players work?

With minimal loss of quality we are now able to compress music tracks on computers so we can store huge numbers of them. There are loads of formats for music tracks or audio but the mp3 format has become the most popular and many manufacturers have released devices specifically for listening to music in mp3 format. The format itself is simply a way of compressing music tracks. By making them smaller you can fit more onto a device.

The typical components included within an mp3 player are a battery, a small hard drive, a circuit board and a connection. When asking how do mp3 players work we need to take a look at each component in turn. We can dispense with the battery as it simply provides power to the device. The hard drive is the part that stores data, so the mp3 files are held there. The circuit board takes the data from the hard drive and converts it into audio using a digital to analogue converter. The connection allows you to add and remove files from the hard drive via another device and to charge the battery up.

Now for traditional CD quality sound just one second of audio takes up more than 1MB of disk space. Clearly you aren’t going to fit many tracks on a small hard drive. The solution is to use codecs (compression decompression). These compress the audio into as small a size as possible without losing too much of the audio data. There is always a balance between size and quality. The result depends on the quality of the codec used and the bit rate at which it is encoded. The bit rate is always measured in kilobits per second (Kbps). The mp3 codec is able to reduce files to around one tenth the size of the original uncompressed source without a significant loss of quality, although there is inevitably some loss of quality.

In order to store the data on the hard drive it is basically converted into a series of 1s and 0s. The original uncompressed source files hold audio data that the human ear cannot even detect; if two similar notes play close together or a loud noise plays over a quiet noise there is evidence to suggest we don’t hear the second note or the quiet noise. This information is stripped away in order to reduce the amount of data that needs to be stored. This study of how we process sound is a growing field known as psychoacoustics.

In simple terms the audio is stored as a digital file on your mp3 player and when you play a track it is converted back into an analogue signal which is broadcast or amplified through headphones or speakers. Hopefully that answers our original question of how do mp3 players work. If you would like to read more on the subject then you’ll find a detailed discussion of mp3 players on How Stuff Works.