Well it took me a while to figure this out, but after I re-installed windows 8.1 on my pc, I lost all sound in Arma 3. All my sound drivers and windows drivers were up to date. After a few days I decided to go through the list of audio software I had on the previous install. A little app that comes bundled with Dirt 2 and Dirt 3 did the trick Its called Rapture3d by Blue Ripple Sound. I installed this and beautiful sound from every direction came back to Arma 3 I use the Logitech G430 USB headset by the way, in glorious 7.1 surround. It works with my Asus D2X sound card as well. Try it... Rapture3d. I hope it works. http://www.blueripplesound.com/get-update or http://www.blueripplesound.com/downloads/uv6aciq2/rapture3dgame_2.6.6_win.exe