I have the 5660 and recently got my 6th speaker for a 6.1 setup. Is there any way to get the receiver to make a matrix'd 6.1 out of DolbyDigital 5.1 ?? I tried everything. A friend has a RXV 1300 and can flip to a matrix'd 6th channel when viewing a DD 5.1 soundtrack. I seem to be stuck in 5.1 and my 6th speaker lies silent.