Acoustic Die Audio SP-8c are the best ceiling speakers I have ever heard. I only have 1 Acoustic Audio SP-8c set and it is connected to a 5.2.4 system. I hear EVERYTHING around me! My setup: Onkyo TX-NR787.x2 Klipsch R-820F (front).x2 Klipsch R-620F (rear).x2 R-120SW (subwoofer).x1 R-51M (high mounted front pair).x1 R-34C. (Center channel) x1 Acoustic Audio SP-8c (pair on center ceiling) Best system I've ever had!