Probably with my upper and lower M22's and VP160, it does the same job as what the height channels supply, except the sound gets anchored to the center of the screen instead. I still like my setup with M22's L/C/R across the top and with M22's as L/R on bottom with VP160 in lower center position. (And 3 QS8's for 6.1 + EP500).
I rarely hear anything coming out of my single rear speaker, that I can identify as anything other than ambiance, but while watching Harry Potter and the Deathly Hallows, part 1 the other day, someone said something that only came out of that speaker. That tells you how little 6.1 or maybe even 7.1 does to the listening experience.
