I just recently purchased a Bohlender Graebner Radia X1 center channel which is rated at 93 db sensitivity and 4 ohms impedance. My Pioneer Elite VSX - 33TX recommends speakers rated at 6 - 16 ohms. My mains are Def Tech BP10's. Should I be worried about this combination this setup considering the impedance of my center channel ? Will this affect the reliability of my receiver ?