I am new to this forum, but from my cursory observations of this and other discussion threads, a small group of long-time audio-bros keep posting among themselves, sharing some insider jokes and taunting and patting each other on the back, instead of providing anything of substance or general value. Guess their knowledge of the AV gear comes down to mere peddling and interconnecting, rather than actually designing, building, measuring and using it.
The truth of the matter is that most AVRs are, technologically, behind the curve. All this nonsense about energy-inefficient Class A/B being "audiophile grade" but other classes being not. Since none of the leading AVR vendors, including Yamaha, seem to have official plans for more energy- and space-efficient as well as lighter-weight solutions, I asked my question about Class D amps on this thread, since some of the AVR owners, including those of Yamaha, may want to explore a similar alternative upgrade path. Sure, I may not get all the answer I could otherwise, but in the case of PSB speakers (admittedly, unrelated to the Yamaha AxA AVR line) the responses were multiple and quite informative -- thank you again.