I have modifed dMC R9 beta 3 so the wave compression codec will correctly write a mono wave file when the source is in stereo (CD for example). Previously the mono file would clip and sound too loud.

Download:

http://www.dbpoweramp.com/beta/dMC-r9-beta3.exe

1.4MB

Please let me know if you have tried this and your results. I have yet to update the Lame and Ogg codecs that also seem to be affected.