Regarding the reproduction of theatre ambience I read once that you should not expect that a recording of a Steinway Grand Piano playing on your stereo would sound any different than it would if that piano was playing in your living room. If you can imagine the overload that instrument would produce playing in such a small space then picture a full orchestra sitting in your house.Thats a good use for the Sonic T-Amp as a computor system since it sounds worlds better than the standard computor fare.
I don't know about SACD; maybe because there are no programs as yet to read SACD to the soundcards on the computor?