I've always thought the weakest link was the listener. Your speakers are capable of very nice sound so I would question your other components. If possible borrow some source and amplifier components from a friend for a demo. System synergy is such a big thing that just purchasing components, even decent ones without matching them is a big crap shoot. I assume you've tried moving your speakers around, checking polarity, and experimenting with different speaker cables, power cords and interconnects? Are your components functioning as they were designed? If your using a PC as a sourse, is it connected to the same AC line as your other gear, a real no no.

WASAPI plugin. While your loudspeakers have relatively high sensitivity, they might benefit from increased and better quality power for improved dynamics. I would look for something with at least double the power of the NAD. Perhaps an Anthem Integrated 225, Music Hall A70.2, Cambridge Audio Azur 740A or 840A, or NAD C 375 BEE. I would also look into some relatively unobtrusive acoustic room treatments like RoomTunes.

Have you heard of rugs and curtains?

Room treatments don't have to come from the agricultural school of design. A plush throw rug and some heavy curtains can make even a truly awful sounding room sound better.

bigD I feel your pain. I also have a pair of Monitor Audio RS6's. I have struggled t get them to sound good and have failed. I think my room may be too small for them. My system consists of a Marantz SA 8001 and highly modded Rega Planar 2 with latest motor as sources. The speakers are driven by a Krell S-300i integrated amp. I can get deep bass, high volumes but I can not get what I consider to be music. I found that the speakers have good attack but very short decay. This makes them sound somewhat relentless to me. I am only about 7 feet from the speakers and that in my opinion is too close.

I am currently using a smaller speaker which I think integrates into the room much better. They make music for me. My RS6's and an Onkyo A-9555 integrated amp may end up in the back of my brother's vehicle this Christmas.