John: I had a Sony DB930 until recently. I did set the centre speaker up closer than it's physical distance, and I did notice a difference. Not much, but enough that I thought it was better. As Larry says, it is a timing thing more than anything else, but you should be able to physically notice if you flick back and forth.

My speaker set up was essentially the same as yours, and I set the rear corner speakers as high and side. But the whole method of setting speakers on the Sonys is odd compared to many others; and today it is even more confusing with the whole surround issue. Used to be easy with ProLogic, because you set the delay. That setting is "hidden" behind other names now. Of course, today's stuff has quite a different set of requirements than plain old PL. ... Mike