That's kind of the point, I understand the power of the amps is different and more channels if you actually need them but is the processing different? Room correction different if using Audyssey? If not, and especially if you are using external amps then is there really a difference that is worth noting (between 6500 and A1H) I sure hope so but I'm not saying I'm asking. I think Peng had a good response earlier.
Different dsp IC and room correction are the two things that will make the A1H sound different, that's 100% certainty because the differences will be measurable by REW or similar ways. That being said, sighted listening is a huge factor regardless, and for some reasons, that appears to be something that people cannot seem accept regardless what they have been told (mostly regurgitated by people like me, HD, even experts like Gene, Dr. Sean Olive and Dr. Floyd Toole.
Most want to believe that the differences they heard were so significant, even night and day so they could not imagine/accept it would make a difference if they did their comparison in DBT or even just SBT. In the case of the A1H though, just knowing that it measures as good as the A10 (based on Masimo's own measurements), is enough for me to think it is the AVR I would ever want, if I have the need, even if I cannot hear a difference between it and an entry level AVR, that's just me and I know it makes no sense to others lol.
I'll be interested to hear from the OP regardless, and I hope he likes it, I wouldn't want to have to return a 80 lb box.