Others here are more knowledgeable about this stuff than me, but I'll give you my opinion and experience. Based on my system (NHTs shown in my sig, using an amp for only the two fronts channels), my listening levels, and my hearing - I sure don't think that you need the same amp for all three. I think that once you calibrate, you'll be fine. That's assuming that the Emo can sufficiently power your mains and the Arcam can sufficiently power your center in regards to how loud you like to listen - if either amp is underpowered, then that will be the wink link. My Pioneer does some auto equalizing, so that helps with getting the speakers match each other (different amps or not).