I've heard several Silverline models in many different venues and all pulled off very good disappearing acts -- something that's very important to me by the way -- so I'm a little surprised at your experience. Is this with all music or just certain recordings? I also completely disagree that Silverlines sound "boxy" (have you found that to be the case at all?), which sounds more like a retailer trying to get you to buy new speakers -- go figure. I'm assuming you've experimented with placement and gotten them sufficiently away from side and back walls and that they're hooked up correctly. If it's not placement I'd start to suspect a problem either with the speakers or upstream equipment. You might also try calling Alan Yun of Silverline as I've found him to be one of the nicest guys in the business so he may well have some helpful suggestions.
If at all possible I'd try to borrow another pair of good speakers and see if you have the same problem before going to the trouble/expense of buying different speakers. Hope this helps and best of luck.
If at all possible I'd try to borrow another pair of good speakers and see if you have the same problem before going to the trouble/expense of buying different speakers. Hope this helps and best of luck.