OK, I'm a little confused now.
Thanks to basshead81, ThinkRationally, Tim Akin for your input.
I can't find mention of "X-Bass" in the pdf of the manual, so I'm not sure what its purpose is, but let me see if I understand so far...
I can set my fronts to small, select 2ch stereo, and still utilize the subwoofer "as per the crossover frequency" as long as my sub is turned on, but the specific X-Bass feature won't apply. So, listening to music, I'll have output from fronts and sub, meaning I can get a clean sound without DSP effects, but with the added punch of the sub. I like to direct the bass away from the speakers so they aren't overworked. I'm not an audiophile or expert, but have read it's best to do this so the speakers can concentrate on other ranges that require less movement.
But if I were to change the fronts to "large", I could employ the X-Bass feature in 2ch stereo mode. I've read in multiple posts that it's ideal to keep the fronts set to small, though, and my fronts are indeed physically small--they're large bookshelf type.
Or I could use the 7ch stereo mode which allows for using X-Bass. I'm assuming that 7ch stereo mode splits the stereo channel among however many speakers you have connected? IE, it's not a surround mode, but stereo split among multiple channels. And can 7ch stereo mode be used if you have 5 speakers only, plus sub (5.1)?
As long as 2ch stereo can be used with the sub, I expect that will be the mode I'll prefer for music.
Have I got that right?
And perhaps someone can explain what X-Bass is.