Just from looking at Axiom's site, I'd probably suggest starting with a 40Hz or 60Hz crossover for the front speakers (M80), 100Hz crossover for the center (VP150), 100Hz or 120Hz crossover for the surrounds (QS8), and I'd bypass the crossover on the EP500. As for the Trim setting on the EP500, based on the manual I'd start out with it set to "Flat" initially. The "Half" or "Full" settings may be useful if you have a problem with the very low bass being too powerful in the room due to acoustics problems, at least according to the blurb in the online manual.