Axiom designs their speakers to be flat, to not emphasize any one part of the audio band over another.
If the amp is buzzing, that is almost always the transformer. The power entering the amp is not a smooth sine wave, and the harmonics are causing the transformer to vibrate. Some amp makers will embed the transformer in epoxy, or attempt to dampen it some way. Others say, "use clean power". If it is exceptionally loud there may be a physical defect either from manufacturing or something got jarred loose in shipping. Definitely see what Emotiva has to say.
The 3808 should be able to run everything just fine. What is it that you're not getting that you hoped the amp would add? Chances are you can improve things greatly by adjusting your speaker layout, and adding some simple treatments to the room.
