I am looking at all options for a 9.1 capable receiver as I would like to try Dolby IIz or Audessey DSX height, but I do NOT want to sacrifice my back channels in the process. It doesn't matter if an external amplifier (pre-outs) are needed to get to the 9.1 channels, I just want to make sure the back channels AND the height channels can be output simultaneously. It seems a vast majority of economical receivers offer a choice and do not allow one to use both at the same time. To me, there is no way I would sacrifice the back channels for height, but if I could do both, I would try it. Thanks.