Hey Spirit_Rises, welcome to the forum. I own eleven Emotiva amps right now and have owned about fifteen more that have been traded or sold. I have not had any Emotiva amps that hum or buzz outside the regular slight hiss with your ear to the tweeter of 100db efficient Klipsch speakers.
Red to red and black to black with the power off is all you need to worry about for hooking up the speakers to your amp. I don't believe your Denon offers XLR outputs otherwise i would tell you to use them in lieu of the RCAs, they always sound better, hold tighter and offer higher gain. I hope you find what you are looking for. The XPA-5 is a nice amp and should be plenty to power your speakers.
Tim