Sorry if this has already been discussed, it's such a monster thread at this point.
If my main use case is 2ch upmixing for music, what would you say are the requirements for surrounds/heights? That is to say, for discreet content you'd want all speakers to be of similar capacity (reality is different, of course). But for upmixing, almost always Auro3D in my case, is there even anything happening below 80Hz on the bed layer surrounds? Below 100Hz on the height layer? I know Gene did some frequency analysis between Dolby, etc, but I don't believe he went that deep.
Because this system is 99% 2ch, I don't use a center if that matters somehow. Thanks!