I have noticed that the sound of dirty bomb is quieter compared to other games.
E.g. my system volume is @ 50% and everything is loud enough for me. But when I have started DB, I have to set my system volume up to 90% to have the same loudness level!
I am wondering whether this is a DB specific thing or whether is it my system!
Not a really big issue but it would be nice to know whether other players can confirm or deny this sound phenomenon! 
An Asus Xonar D2 is working in my system: