Don't turn them around! If you want less high end sparkle, toe your speakers out a bit. You will be rewarded with a wider deeper soundstage. Most people's speakers are toed in too much because their room is absorbing too much high frequency content. You want your room to have lots of sparkle, if you looked at it on an RTA, I bet you'd find that 16K is still down a few db and 20K is down even more. By toeing out the speakers, the high freq content can still interact with the room giving you a huge sense of scale, but without beaming at your ears first.
Let me know how that works.
Nathan