I have tried inverting the phase on the sub and don't find the results satisfactory. I have a Velodyne SPL series sub, its a compact sub with a 10 woofer a very high power amp. I get way better bass out of the sub with the S30's with all settings the same. The sub is pointing right to left in the room, maybe that's why the phase doesn't have much affect on the sound. Maybe if the sub was facing back to front it would make a difference. That's why I would like to try it facing the same way as the front speakers like it looks like you have yours which I would have a hard time doing with the towers or using stands, although it sounds very good where it is now with the 30's. Doe they get too boomy when they are closer to the wall? I'll get back to you tomorrow, have to hit the hay. Thanks so much for the info so far.