I have the denon 4802 receiver and I was wondering if the axiom m80ti towers would work alright with it? I noticed they are 4 ohm speakers. Can you mix 4 ohm and 8 ohm or 6 and 8, etc...? Also I noticed there surrounds are 6 ohm. Are they gonna work ok with it also? In the end I would like to have all of the top axiom speakers for my Home theater setup but I noticed they have differents ohms. Whats the difference between 4,6,and 8 ohm speakers?