Compressed audio is the way to go when you're ripping your own music or creating a digital media archive. But the original digital music files you find on a CD are uncompressed, as are digital sounds used by your computer's operating system. If you insist on archiving your music in its original unaltered form, you'll want to use one of the following uncompressed digital audio formats:
- AU—A file format (abbreviation for "audio") that originated on the Sun and NeXT computer systems. Not widely used today.
- Audio Interchange Format (AIF, AIFF)—File format for Macintosh system sounds, similar to Windows' WAV format.
- Compact Disc Digital Audio (CDA)—This is format used for encoding music on all commercial compact discs. If you buy a CD from a store, the music on that CD is stored in CDA format. Unfortunately, your computer can't store files in CDA format, so you still have to convert CDA files to another format to store on your hard dis.
- SND—Another file format (abbreviation for "sound") similar to the AU format and used primarily for Macintosh system sounds.
- Waveform Sound Files (WAV)—This format (pronounced "wave") produces an exact copy of the original recording, with zero compression. The result is perfect fidelity but with very large file sizes—the same size as the original, in fact. It's not a good choice for portable use, because it takes up too much storage space, but it's the preferred format for uncompressed archiving.
There's one last digital audio format that you should be aware of, even though it's not used for recording music from CDs. The MIDI format, short for Musical Instrument Digital Interface, is used by professional musicians to reproduce instrumental music in very compact files. MIDI doesn't record an actual performance; instead, it creates a kind of roadmap for frequencies and rhythms that can be fed to synthesizers and other musical instruments for playback. It's often used to create background music on Web pages (with .MID format files), and to record musical "sequences" for various home- and studio-based recordings.