AAC

AAC is a modern lossy audio format that often achieves similar quality to MP3 at lower bitrates. It usually appears with the .m4a extension.

Most DJs end up with AAC files without going looking for them, because it is what Apple has used for purchased music for years. Those purchases are ordinary files you own and can load into DJ software like any other.

Sound quality is genuinely a little better than MP3 at the same bitrate, so a 256 kbps AAC holds up well. Support is broad across modern DJ software and club players, but it is still narrower than MP3, which is worth remembering if you ever have to hand a USB to someone else’s equipment at short notice.

AAC has some compatibility gaps

• Serato on Windows does not read files with the .aac extension at all. Serato lists AAC as Mac only, while .m4a works on both. Their workaround is to convert the file or re-save it as .m4a. See Serato: Supported File Types and Serato: known issue with .AAC on Windows.
• Traktor on Windows needs Apple QuickTime installed before AAC will play. See Native Instruments: Which audio file formats does TRAKTOR support?.

If you keep AAC in your library, sticking to the .m4a extension avoids most of this.

See Also

MP3, Lossy Audio, and file format