Hello forum, need your expert assistance please. When I play a DVD in the DTS, 5.1, etc mode seem the voices from the center speaker are too low. I turned up the center speaker to the maximum volume, +12. I love the DTS mode but seems I have to crank up the system in order to hear the voices. I double-checked all my connections and there fine. I'm using 16-gauge cable. My audio is connected via the optical cable from the DVD to the receiver. Is there something I'm overlooking and can do to correct this problem? Thanks for the help!