ub-zero

Hi all , just seen some quick advice here . I have a friend who has a system with the following equipment . 6 x 140 - 450 4 hms W Sub-Zero Ice SS3328 Wired in Series 1 X subwoofer Yamaha NS-SW050 50 W (100 Hz, 5 ohms, 10% THD) Denon AVR-1603 Receiver 80 Watt - 8 Ohm - 20 - 20000 Hz - THD...