This is a simple mod that basically replaces most of the sound effects with ones that sound more realistic, meaning if there is an explosion in space, it doesn't sound like its on earth. The audio is more muffled, because its in space...a bit like in Battlestar Galactica or Firefly.

Demo:

https://www.youtube.com/watch?feature=player_embedded&v=PsIzPaSIyK8