I need to choose an amp for my setup, which is for a 12 x 5 metre room, with the TV cabinet in one corner. I have rigged 2 x JBL Control1's at ceiling height as L/R and have 3 more as rears and Centre. The 2 L/R speakers are run via a JBL SB-1 which has it's own crossover.

Will the amp generally run the sub from a separate output? (in which case do I need a 6-channel amp?, or is that standard) or are the L/R pair best left run through the sub, and regarded as simple L & R speakers? I also think that the impedence of the sub/control1 combo is 4 ohms; on the basis that I think that most amps are rated to drive 8 ohms, will this be a problem?

Many thanks