Using this set up what would you use for a 6th channel?

Frnt L/R M22
C vp150 and 2 qs8's

Thanks
Matt

I have the same setup, and I use a M2i for the back channel. I love the way this system sounds.

I also used M2 for my rear channel and it sounds great.

I've got 7.1, and I have a pair of M2i's in the rear.

another qs8
or an m2i