Had the same issue with a Luxman 590 AX II trying to drive a pair of KEF Reference 1 Metas. It was a totally lifeless presentation with no bass. I brought the amp to my local dealer, thinking it was defective. It was not; the amp could not drive the speakers. I purchased a pair of McIntosh MC 611s, and the problem was solved. I could fool you into thinking that I am running subs!
BTW, I posted here, and most said it was my room. It is your amp; change it out. Room treatments are highly overrated. No matter what you do or how much you spend on treatments, you will not bring life to the system—best of luck.