Waver

Waver converts WAV/MP3 files to WAV or MP3 using all processors in the system. Windows audio codecs are used for WAV/MP3 to WAV conversion.

Waver both reads and writes MP3 files. It is also capable of writing WAV encoded MP3 files using LAME and Blade encoders. You can up or downsample your files, change the number of channels and the format all in one step. Waver can also batch convert your sound files.