When I unplug the speakers the option in the preferences menu reverts to internal speakers. The other option visible in the sound output device menu is 'Screenflick audio device, and for some reason ...
I have a 7.1 USB sound card from Startech with 3 discrete 2ch outputs. It's a Startech ICUSBAUDIO7D. It uses a C-Media CM6206 chipset. I have kind of a weird intended use case for it and I don't know ...