OP,
Just a thought… “fatiguing” doesn’t usually come from speakers, although it can exacerbate it. It usually comes from the electronics in the form of high frequency hash and distortion. It takes a lot of experience to really put your finger on it… but fatigue is the sign. Your Rogue equipment is not known for it… so, I would look at your source. If it is supplying the high frequency problem then it’s going to come out the speakers. If your room is not heavily sonically dampened then that will make it worst.
Can you borrow a real high quality streamer or CD Player . Try some dampening material in the walls behind… carpet in front of speakers. I would verify this is not you problem before proceeding.