Ghost, the center channel is primarily for dialog (voices) during movies, not explosions. Setting your mains to large, which they should not be, will not help what I think your describing as "fullness".
Explain why 'they should not be'. While I don't know if setting them to large will bring the 'fullness' he feels is lacking, wouldn't setting your mains to either large or small be a personal preference thing, and not a 'right or wrong' thing? While I understand the motive behind setting a main speaker to small perfectly well (send all the bass information to the subwoofer), I still believe there is room for difference of opinion in the matter.
In one of the subwoofer threads (probably my own) I talked about my preference towards smaller subwoofer speakers, like 8 - 10 inchers because of the 'tight, fast bass' they produced. The 13, 15 and 18 inch subs hit much lower, but they were much slower, not nearly as detailed, and all around just more vague. It is for this very reason that I leave my M80's set to large. This way I get all the frequencies down to 35 or so hz played through the tight, fast 6 1/2 inch speakers instead of the slower 12 inchers of the EP800. Not that the EP800 is sloppy by any stretch of the imagination... its just that compared to the M80's it is.
So anyway that's my own preference. I feel the M80's handle 35 - 80 hz better than the EP800 does, and I don't feel leaving them set to large takes anything away from the EP800's performance. I wouldn't go as far as to say mains 'should' be set to large, I just don't think it's a black and white situation. Try both set-ups and go with your favorite.
