I noticed that when I switch from my speakers to my headphones some of the sounds, most noticeably music, stops working and I have to re-launch the game to get everything to play. This happens when I turn my headphones on and switch them to the default device in the "playback devices" menu in Windows 7
not sure if it still works, but in beta, i found that if you changed the sound quality to something else (eg. high to medium, then back to high), it fixed any channel problems like you're describing. edit: nvm they removed that option, instead now just change the 'maximum voice channels' slider.
