I don't know about "surround", but they have speakers in the back of the piano facing the wall that allows music to reflect off the wall as well as project from the additional speakers in front. Of course it's best to position it a few inches away from the wall for the greatest effect.
This is an awesome instrument!!! I was about to puchase one 'til I found a good deal on a Samick grand. See my earlier thread: http://www.pianoworld.com/ubb/ubb/ultimatebb.php?ubb=get_topic;f=1;t=005303
The sound, when I tried it out in the dealership was fantastic! I compared various notes (like high-C, A above middle C, and low-A) with a nearby Yamaha grand and I could not tell the difference! Of course I'm a relative newbie, but I definitely could tell the difference between my Yamaha DGX-500 "Portable Grand" keyboard at home and the CLP-170 at the dealer.
While high-C sounds "better" and more high-C-like on my keyboard, it doesn't sound like a real grand piano high-C. The high-C on the CLP-170 sounded exactly like the high-C on the grand.
The action, which was important to me, was very nice. Like I said, I was about to buy one (because I wanted a digital for my home office), but the expenditure for the Samick has postponed the digital purchase for quite a while.