An MP3 CD is a type of music CD that contains compressed data files instead of music files and is created in a different format than regular CDs. These CDs allow more music to be stored on a single CD and offer several advantages over traditional CDs.
Traditional music CDs are burned in the Red Book Format, meaning the data must fit a certain number of specifications and the CD is designed to be played in home audio systems as well as computers. Data CDs are burned in the Yellow Book format, which is not as strict about the type of data contained on the CD. MP3 CDs are created in the Yellow Book format, allowing flexibility with many types of audio-compression standards.
MP3 CDs are played in much the same way data CDs are, except special hardware or drives are often needed to read them correctly. In computer systems, the CD or DVD-ROM drive is already equipped to read MP3 CDs and will open them as data files for the user to choose. Newer home audio CD and DVD players support MP3 CDs by including special decoding software in addition to the standard software and hardware. Depending on the player, the files may display on the screen for the user to choose, or they may play automatically without a visual interface. Note that not all home audio and car CD players can play MP3 CDs. Check your device's documentation to be sure.
MP3 CDs allow for more music to be stored on a single CD, offering numerous benefits in portability and ease of use. A standard CD can hold about 18 songs, while an MP3 CD can store about 138 songs. Depending on the type of audio compression used, there is potential to store even more.
Because MP3 CDs use software-compression technology to reduce the size of the music files, there is an inevitable loss in audio quality. This can be detected easily in high-end audio setups, which expose more detail in the music than inexpensive speakers and headphones. This is frustrating for audiophiles who strive for the most accurate reproduction of music. They can immediately detect the lower quality of compressed audio and avoid using it despite its advantages.
When creating an MP3 CD, the user must compress the audio files to reduce their size. MPEG-3 (MP3), Windows Media Audio (WMA) and Advanced Audio Coding (AAC, used by Apple) are three common compression technologies in use.