center channel problem

I have a new home theater with thiel 3.6s as my fronts, marantz preamp, and parasound 5250 amp. Center is a thiel scs3. i'm very dissappointed with the scs, boxy and muffled. Dialog is uninteligible. Any thoughts on how to improve the center channel or a good center channel to match the 3.6.

BTW I tried the 3.6 in the center and it sounded great (but covered half the screen).
Did you try Phantom ?
You might want to try the "small" speaker set up. Helped in my case.
make sure the tweeter is working. this exactly described a problem I had, and my center channel tweeter was blown new out of the box.
I use an scs3 and it is clear and crisp, just the opposite of what you discribe above. Either the tweeter is blown or your surround sound processor is not working correctly.
You should probably look for an MCS1... one of the best, if not the best, center you can possible find.
I used to have the SCS3's in my system for an audition, as I used to sell the Thiel line. I would probably suggesty you get the large MCS1, and forget about it. The SCS3 is not so great a speaker. Not so open sounding, and rolled on top, from my recollection. Also, dynamics are underwhelming. And while the MCS1 isn't the strongest on the plannet (you will DEFINITELY cross it over at 80hz for best performance, and care for placment), it's much better than the SCS3. Also might try the SCS4 if your'e budgeting, and looking for small center speaker. It has to be better than the SCS3, at least. I would not recommend the scs3 speaker if you can avoid it.
My approach to filling my listening room,with sweet music, is
"out of the box", but, the results, simply can not be argued.

For you, that single woofer, single tweeter, is just not

Making the cut.

Only you know what you need, when you find it,
Your ears will confirm it.

I suggest trying out some speakers, in your home, if at all

I Love Music!