chapter 4 audio bug

[RatMan]

On my first play through in chapter 4 everything acted normal until I had my first death and the voice audio kept getting quieter and quieter until I couldn't hear it anymore and I couldn't hear Ollie to get the generator back up and now every time i restart from a previous save the is no voice audio at all, even after I've uninstalled and reinstalled the game. I really want to finish this myself instead of watching someone else play it but its nearly impossible for me now. before anyone says anything I cant use subtitles as I'm a slow reader and it ruins the experience especially when I'm trying to play the game and read at the same time. is there a fix for this?