GarageBand For Dummies, 3rd Edition

Chapter 20

File Compression and Your Music

IN THIS CHAPTER

Learning about compression

Making AAC and MP3 files

Distributing your music

The first release of GarageBand exported exactly one file format — the Audio Interchange File Format (AIF or AIFF). Today, GarageBand on the Mac can export your song in pretty much all popular file formats — AAC, MP3, AIF, and even the Windows standard for audio, WAV (or WAVE).

You can’t export an MP3 from GarageBand on an iDevice, but you can export AAC, AIFF, and WAV files, as well as Apple Lossless files, which aren’t an option on the Mac. AIF and WAV files are, by definition, uncompressed. Files compressed with MP3 or AAC are much smaller — 50 percent to 95 percent — than an uncompressed AIF or WAV file of the same song.

Compression, by its nature, removes part of the sound in the file. In theory, it’s the part that people can’t hear, but some people notice a big difference between uncompressed audio and compressed audio, even on cheap stereo systems. Many others can’t tell the difference. It’s a matter of degrees. Some people notice the difference between compressed audio files encoded (ripped) at bit rates of 160 versus 192 Kbps. Others hear ...