The AVR will be able to do 9.1.4 or 7.1.6 (w/Front Wides); however, it is not able to expand beyond 13Ch (ie. no expansion with 2CH amp).Oops. Brain fade. Sorry.
With the DTS:X Pro update and 13 on-board ch, one presumes that the X8500 will be able to do 9.4.1, with the two extra being "wides". Do you have any idea if the X8500's smarts will be able to recognize 9.4.1 with top center and VOG in lieu of wides? Or if it can recognize 9.4.1 as "wides" plus top center and VOG with no "rears". And back to my original question, which I mangled: Will the X8500 be able to do 11.4.1 with the addition of an outboard 2 ch amp? All the connections are there for 15 ch and I have 15 speakers connected so that the X8500 automatically hooks up the "correct" 13 speakers when an Auro source is detected. At present, I have disconnected my rear speakers so that I can have "wides" under the current DTS:X 11 ch limit. Looks like I'll be able to hook them back up with DTS:X Pro, but I'd be happy to add an outboard 2 ch amp to get simultaneous 15 speakers with top center and VOG.