Ok spent ahwile going over the threads on this, found a few answers, but a few contradicted each other so I will put mine up here, in case it's an unrelated event.
I purchased ARMA II and OA yesterday via steam. I am running a 5 month old tower on Win 7 64bit. Beats audio card (does it on both sound cards though). I am running steam, ARMA and ARMA OA as Admin. Now when I was playing regular ARMA, the sounds were way off. They sounded almost mono, and with bursts of static when running or moving, driving, etc. Now I know all my drivers are up to date as well as current version of DX 11. The tower I am running is an HP model P7-1154.
I figured it was something with my system. I played OA for the first time as well today, and it runs just fine, sounds are perfect. Any help on this would be appreciated.