when I tried any of the DSD options, JRiver stopped playing - apparently HDVD 800 doesn’t support DSD – is it true and would I get better sound quality with DSD and if so which of the DSD options should I select?
If it doesn't support DSD, you don't enable any of the DSD options.
Under ‘sample rate’ I selected 192,000 Hz for all ‘output’ (is this correct?). I use JRiver for playing CDs only. Under ‘audio path’ it now shows ‘input 44.1Hz 16 bit’ (from CD) and ‘output 192 kHz 32 bit’ Is this correct for best sound quality?
Do this if you want Media Center to upsample from 44.1kHz to 192kHz.
Set them to "no change" if you want to send a 44.1kHz signal to the DAC.
Which sounds best depends on the hardware. If you can't really tell a difference, I would send the DAC an unchanged signal.
Set the 352.8 / 384 / >384 kHz options to the highest factor that the DAC supports. (probably 176.4/192/176.4)
I didn’t select Headphones crossfeed (should I select it?)
Do you want crossfeed?
Try changing the options while you have music playing to see if you like it or not. Crossfeed can make headphone listening a bit more natural sounding.
Under ‘channels’ I selected ‘source number of channels’ and thus ‘no upmixing and downmixing’
You should select "2 channels (stereo)" with JRSS mixing enabled, or else you will probably get errors if you try to play mono or multichannel tracks.