5.1 or 7.1 and dipole speaker placement

[EddyHorn]

My room is approx 4.5m x 3.2m, my TV will be in the middle of the 4.5m wall and my seating is backed up to the opposite wall. For rear speaker duties I have 4 Kef Q2ds available to me and my amp is capable of 7.1. I'm trying to decide if to use all 4 or only 2. Now I'm pretty sure a pair want to be on the side walls in line with the seats but I'm not sure on mounting height and if to put another pair on the back wall. Kef recommend mounting at 2m would this be the best position? It would seem to suit if I use all 4 as the rear wall mounted pair would be above the seating position instead of right behind the listeners heads.

Any advice gratefully received.

 

[EddyHorn]

I've decided to try all 4 surround speakers mounted at 2m. Thanks to everyone who replied for their help.