why don't you try GX:Transcoder (recently posted here by Rastabt
http://www.dvdrbase.com/showthread.php?t=40130 )
GX:Transcoder
http://www.board-24.de/en/index.html
it's a flexible audio converter, which is able to convert in a batch mode between a lot of audio formats.
Additionally the Transcoder uses plugins to add more functions for transforming and playing audio files.
The GX::Transcoder in it's standard version is able to en- and decode MP1, MP3, MP2, MPC, OGG Vorbis, PCM up to 7.1 Channel, G.721, G.723, G.726, G.729, ADPCM, GSM, VOX, DSP and RAW files as well as decoding QuickTime MOV and QT files. There are also AddIns available, which extends the Transcoder to handle the formats AAC, LA, LPAC, WMA, TTA, OptimFrog, WavPack, FLAC, rkAudio and Shorten. There are plans to support even more audio formats.
The GX::Transcoder can transfer the tags ID3v1, ID3v2, APE v1 und v2, Vorbis Comments.
For private use the GX::Transcoder is Freeware.