Bass traps/room treatments

I have sloped ceilings in my room, too (my forehead is also sloped, so be careful), so I know they are a mixed blessing. I also use a long wall set up and I have recently added some ASC products. But before I did that, I spent a year adjusting speaker placement, and I agree with Fliceswater that you should work on placement first. The SC-IVA is a bear to move, I'm sure, but as tall as they are, and as different as the two sides of the room are, placement will be critical. My room has slopes on the long front wall and on one of the side walls, both from 8' to 13, with a flat ceiling from there. I had some bass problems, but the biggest issue was image wander and balance. I have ended up with the one speaker about an inch farther out in the room, and I sit in the near field and slightly off center. This works better than using the balance control, where I could never make a fine-enough adjustment to get a solid, consistent center fill. I suggest that you try moving your speakers well away from the corners and the front wall, point them almost straight ahead, and sit close to the rear wall. As you probably know, the word is with the IV-A that you should not sit in the near field or you won't get good integration, but I would start too close and back them off until you start getting too much reinforcement from the front wall. The speaker with more air around it will sound farther away, and that one should be pulled a little closer to the listening position. In my room, the speakers are fairly close together and far from the walls, and the soundstage goes way out beyond the speaker locations. You might also try moving the speakers off center, away from the low end of the room. This may be a cure worse than the disease, creating a sidewall imbalance, but you must get a ton of ceiling bounce from a 7' speaker in a 8' space! Once you've gone through all of that, try adding some tube traps. ASC's customer service is great and their products are worth a try, but there are no shortcuts with funky room acoustics. Also lookup the Audio Physic website and Micheal Fremer's review of the Physic in Stereophile, where the long wall set up is discussed at length. Let us know how it goes.