Just a quick suggestion and possibly a cheap solution..
If the Emotiva has pre-outs and the sub has RCA inputs.. connect them! Switch the Emotiva to pure stereo bypassing all processing. Set the sub crossover manually on the unit.
I did this with my Rotel and the difference was outstanding.
Hi mickey... I'm thinking of your post and still trying to figure out how that would work in both Stereo and HT modes.