ArmA 3 uses XAudio2+X3DAudio. This means that your game uses your Windows settings. Sound engine only handles up to 5.1 output, so that's why you might be having problems. This sound engine is very very bad, if you have proper headphones (not your crappy 7.1 lol headsets) you will have them set to stereo and the sound engine will only emulate 2 channels (left and right). This is where gaming audio has fallen to...

FlatnikG I still play Project Reality. The 1.0 version is coming out in few months witch an even revised sound mod. I agree, it's sound is simply the best. Not only the immersion, but also positioning (OpenAL with full hardware support done right). Preview: http://www.youtube.com/watch?v=uPcyl_uPl3g

Keep in mind this is a FREE mod done by AMATEURS (chech www.realitymod.com for details).

Agree with zeep, sound engine is the problem.