QSC 3600W Dual 12" Powered Cardioid SubwooferWith the introduction of the KS 212c cardioid subwoofer, QSC introduces the first in class, single box directional subwoofer. The term cardioid refers to the heart shaped coverage pattern of the subwoofer. Were all used to cardioid microphones. Cardioid microphones are more sensitive to sound energy from the front and reject it from the rear. The cardioid subwoofer does the same thing in reverse producing more energy from the front and less from the