i have a 5.1 speaker set up and i cant really add a center back because my listening position is like 5 inches away from the back wall. i am basically against the wall with my L & R surrounds speakers flush mounted 3 feet up. I was hoping that the DD EX or DTS ES matrix will hopefully provide a phantom back center. in the front panel of my receiver should i just leave the 6.1 switch on or turn it off? the receiver menu also lets the back channel toggle on or off. i have no clue what to do.