For what its worth I am running the NAD C368 with a pair of RP-600M and a R-100SW in a room of similar size with good results, The 2 speakers are in the corners about 60cm out from the wall and about 4 1/2 meters apart with the sub in a rear corner behind the listening position (which is a perfect triangle).It sounds fantastic in that set up however I did try them either side of entertainment cabinet about 6 feet (as above comment) and they sounded awesome as well,I found its moving and angling them in small movements to get the ideal set up.