DVD Audio Problem

I have just finished sorting out a problem i had with playing dvds on my new rig using ffdshow and changing the settings to match this thread. Progressive scan DVD on HTPC - Home Theater PC News
The picture i have is still grainy like before but not as much, but now the wierdest thing happens. When you play a dvd u can hear the background music but whenever somebody talks, or theres an explosion all you hear is the background music. How did i get rid of the main audio? How do I get it back?
Also on my dvd quality is there another decoder better than ffdshow?
Thanks for the help.

I have a similar problem when I play DVDs in VLC Player with audio device set to 5.1, I find changing it to '2 front 2 rear' sorts it nicely.

lack of speech usually means you're strictly obeying 5.1, but don't have a valid center speaker configured