Hello,
While in theory using a monopole speaker in the rear for a 6.1-channel system is accurate, it's my experience that a third identical quadpolar speaker at the rear will enhance the soundfield without sacrificing the directional effects when called for. The multipole radiators in a surround role are especially effective in normal-sized domestic living rooms, and the tonal balance between the two surrounds and the rear speaker will thus be exact, something that's always desirable.
Alan Lofft
Axiom Resident Expert
