I also have a fireplace (fake) with a glass front between my speakers (Silverline Preludes). The speakers are about 8 inches further into the room than the (still fake) fireplace, and 7 or so inches from the edge of the aforementioned (fake) fireplace, so reflections are gonna go sideways and it doesn't seem to hurt soundstaging, imaging, musical content, phase, or lyrical sensibilities (maybe that one a little). I've pulled them into the middle of the room and otherwise tried various degrees of tow-in, height adjustment, spikes, etc., and they sound best pointed straight forward raised up on butcher blocks with vibrapods under them. Also, the little corner the fireplace creates behind the speakers is perfect for a little REL Q150e sub. This information is useful only to me or those exactly like me with identical gear in a room exactly like mine.
