EMX files represent downloads associated with the eMusic Download Manager and are commonly referred to as eMusic Download Manager Downloads.

The eMusic Download Manager is a desktop application developed especially for the needs of the eMusic.com online store and allows downloading music tracks or audio books in MP3 format on a client machine.

eMusic users pay a monthly subscription fee and are allowed to download a fixed number of tracks every month. The store is preferred mostly by people interested in downloading entire albums.

EMX files contain all the necessary metadata needed to point the eMusic Download Manager to the exact location of the MP3 files associated with the album queued for download.

They contain no actual audio data on their own, but only a reference to where the audio data can be located.