Help with imaging

Hope you guys can help me with an extremely annoying problem I'm having. I'm very happy with my Soliloquy 5.3s but seem to have a hard time with vocals or instruments that should be centered...they seem to want to exist to the right of center. I can somewhat correct this by toeing in the right speaker more than the left(I tend to toe speakers in toward the listening spot), but this seems more like a bandaid than a real fix and doesn't fully correct the problem. Moving the right speaker back doesn't seem to help either. Here's the wierd part. When I switch the speakers I still get the same result. I would have expected the center image to shift to the left, but it still skews to the right. I've recently had other speakers in my system and don't have this problem, so I don't think it's the electronics. Also, this happens regardless of what room the speakers are in, so it doesn't appear to be just a room thing, and I've tried different cables as well to no avail.

This is driving me nuts, so I hope you guys have some thoughts or insights and your help is GREATLY appreciated.

Tim