Ok, so I dug an old DVD out of my storage bin and played it.  I am getting sound out of the rear Surround speakers when I play a movie.  I think the issue is how it is processing the Surround signal from YouTube content (which is what I was using to test the 5.1 Surround speakers).   I should have thought to test with something other than YouTube sooner.
I recently replaced my Dell XPS 8900 with an XPS 8950. When I plug in my Dell MPS 5650 Speaker System and try to configure them with the MaxxAudio Pro app that came with the new XPS 8950, the rear surround speakers don't get any sound? When I do a Dolby 5.1 Surround Test, the sound for the rear surround speaks come out of the front speakers instead. Anyone have any ideas how to get my surround speakers to work properly?  Thanks.
XPS 8950, rear surround on MPS 5650 speaker not working