I have a (15(?) year-old pair of American Acoustics bookshelf speakers being used as stereo speakers in a second room off my Sony STR-DA4ES receiver. This is a larger room, 15x20 with a peaked ceiling that starts at about 8.5 feet and runs to about 12 feet high. The speakers are on the long wall. On the left is an 8' by 7' opening to the living room and the back "wall" has a similar opening into the dining room. The AA's are sounding pretty muddy. I'm thinking of these possible replacements: --Aperion 522D-LR --Axiom M3ti --Athena AS-B2 --Polk Rti6 or Rti4 --Infinity Beta 20 Looking for better definition, solid bass. Eventually, I may build a surround system around these new bookshelf speakers. I would stay with whatever brand for timbre matching. This would replace a Definitive Pro Cinema 60 surround set in a 20x15x8 living room. (Or wouldn't those candidates improve sound over the Definitives???)