How to turn on the evrionment sounds effect

Today, I opened some folders under crossfire. I Found a folder named EnvSounds(Crossfire/rez/SnD2/EnvSounds). There are lots of environment sounds under some folders with the names of maps. Some of them are pretty cool, however, I have never heard them in the game. Is there anyway that I can turn them up? So it will be more real in the S&D maps. Thank you