Convert to mp3 with ffmpeg
This rule uses File Juggler and ffmpeg to convert any audio file to mp3 format.
The rule is set up to run on files that are not mp3 files. The command it runs is:
"c:\program files\ffmpeg\bin\ffmpeg" -i "File path" -aq 0 -map_metadata 0 "Current folder\File name.mp3"
You can make the rule monitor your music library, or you can run the rule from the file explorer context menu on the files you want to convert.
You might also be interested in a rule that uses mp3 tags to rename and move music to the correct folder. Take a look.
Download File Juggler
File Juggler is a windows utility for automatic file management. You set up the rules, and File Juggler will monitor your folders and manage your files automatically.