It seems to me the the sub out only affects the sub. Then the high pass will only affect the other speakers. I would think if you set these to the same frequencies you should be good. I can't imagine this is a brick wall filter so both the sub and the mains will be covering a little above (the sub) and a little below (the fronts) a bit of the selected frequency.

Rick


"A fear of weapons is a sign of retarded sexual and emotional maturity." Sigmund Freud