I was thinking of getting an Onkyo TX-NR686 which supports 2 zones and has 7.2 channels. Is it possible to run a 2.1 computer setup and 5.1 TV setup at the same time, independently of each other, off of this amplifier?
According to the manual on page 26, something close should be possible. It would seem you will have to provide your own means of generating the LFE channel, but you can at least achieve a separate stereo output while simultaneously enjoying 5.1 output in the primary zone.
ZONE 2:You can enjoy 2-ch audio in the separate room (ZONE 2) while performing playback in the main room (where this unit is located). The same source can be played back in the main room and ZONE 2 simultaneously. Also, different sources can be played back in both rooms. To output audio from an externally connected AV component to ZONE 2, use either a digital coaxial cable, digital optical cable or analog audio cable for connection. (→p37)
• While ZONE 2 playback is being performed, surround back speakers installed in the main room cannot play audio.
Should be good, most 2.1 setups don't use the sub out on the PC, just the main L/R and the speakers will have it's own crossover to deal with the sub. So just make sure your PC output is simple 2ch L/R and speakers w/ integrated sub, all will be good.