Originally Posted by lefthandluke
is this unique to onkyo products...?
was this offered to denon as an option and turned down, or simply too new a technology to make denon's latest lineup...?
I don't know who turned down what, I don't work for Onkyo, Denon, or Audyssey
Curiously, the Onkyo's approach to it isn't 100% "optimal" either. So it's sort of trade-off between the two approaches.
1) the approach Onkyo took with the x007 models is to treat the subs totally
independently. That means different distances, level matching, and EQ filters. However, the last part (separate EQ filtering) is actually suboptimal, as Audyssey's research strongly supports the idea of EQ'ing the two (or three or however many) subs together as a summed response
2) the Denon approach (BTW this only applies to the 4810, the higher-end 5308 and the AVP actually can do fully independent sub EQ) is to just leave them as a summed response. So it's up to the user to level match manually first, and do your best to time align (e.g. getting equal distance from 1st measurement point), but then in the end EQ'ing the two subs together as one summed unit is actually the better way to do it.
Either way should provide excellent results though.
The standalone Sub EQ products from Audyssey give you the option of either way. The recommended "best" approach is to (1) first time/align and level match independently and then (2) EQ the summed response. So, in other words, neither of the consumer AVR implementations give you the full "optimal" method.
So, if that is a huge concern, do as goonstopher suggests above and add the AS-EQ1 to your existing setup and then ANY receiver will work