In your room setup, the ideal place for FXs might be side mounting high on the walls next to your couch. Although the LSiFX is a bookshelf speaker, it is a big-ass and heavy bookshelf speaker. I did manage to ceiling mount mine, but it required finding a heavy duty pole mount that I could adapt to the keyhole slots on the ports. I think its easiest and most stable to just mount the speaker flush on the wall with the keyhole slots. But that means that you can't aim it and are more limited in placement. However, the side position is exactly what the dipole setting was designed for. In this mode, it is supposed to create a null area around the listening position so that you can't precisely localize the sound to the speaker and surround effects appear to envelop you from multiple directions.
http://www.polkaudio.com/education/t...icle.php?id=27