Access to more output options when using Windows

[Calypso]

I am using a Surface Pro (Windows 11) and in the preferences menu, under outputs I only have (L, R, L+R). Based on the EXCL tags visible in the cal tab, I thought I would get the expanded list? See image of cal Tab. What am I missing? Thanks.

 

[John Mulcahy]

Your output device is the miniDSP Flex, that only accepts two channels from the host.

 

[Calypso]

Is there a procedure that I can follow to safely test the subwoofer, treating it as a third speaker?