Compressed audio file that uses Sony's ATRAC (Adaptive Transform Acoustic Coding) compression; supported by Sony audio devices and the Connect Music Services online store, which has been discontinued; AA3 files do not include any copy protection or digital rights management (DRM).

Important: In order for SonicStage to transfer an AA3 file to a Sony device, the ".aa3" file extension may need to be changed to .OMG.