Re: Voices/audio very low during major cutscenes
Make sure you have made the choices in the game settings for audio: Home Theater, Heaphones, or stereo and the choice is approprate for your system.
I'm using the ASUS Xonar DG in simulated 7.1 mode, and I can hear things better when I switch to headphones (I'm using normal studio headphones).
Otherwise, in your soundcard, see if you have an option for CHANNELS and set to maximum (mine is set to 8 channels).