Another very simple and free way for batch-converting audio-files of even different source formats into one common destination format: Winamp
- put your files into a playlist
- mark the playlist
- right-click on the playlist
- chose "Send to: Format Converter"
- chose destination format "WAV Converter"
- chose destination SR and BR (use the source SR to avoid SRC, like 44.1 KHz/16-bit)
- chose your destination folder and naming scheme (you can set this via variables, very useful for batch renaming of converted files)
That will batch convert all your files on the playlist into the destination folder using the chosen naming scheme and destination format.