An Audio (AUD) field may contain a link to a stored audio.
The Free Mobile Edition allows for one audio to be stored. The Pro Mobile Edition allows an unlimited number of audios to be stored.
When importing and exporting, the full pathname to the audio is used.
The audio is not stored in the database. If audios have been moved to another location, you can automatically change the links: library > right slide menu > files> menu > find missing files.
You can set the directory for files : settings > file storage.