I will agree with Renov8r. Assuming you are playing either a Blu-ray or DVD cut by a reputable producer the discrete channels are much better than they used to be. These days almost 60% of the audio and almost all the dialog is done by the center channel. While it is possible to use the phantom center channel it is not the optimal setup, especially on movies with a lot of soundfield. Using the mains to reproduce the sound of three channels calls upon them to do lots of extra duty in an area they are not likely optimally designed.