Mate when I have your mode uninstalled I have all the sounds including crew voices. All the slides are set as they should be. The moment I install your mode with the custom engine sounds, custom weapon sounds, 6th sense 10 sec indicator, aim mod and some small other stuff that has nothing to do with any crew voices, that's when I have all the stuff I installed all the sounds are working fine but there are NO crew voices. I tried the slides I even put everything on mute except the crew voices. Still nothing. When you instal your mode the settings in game stay the same. And I didn't have this problem with your mod until a recent two updates.
