ART CX311 Stereo 2-Way Crossover with Subwoofer OutThe CX311 from ART is two way stereo crossover network with an additional subwoofer output for low end frequency reinforcement. It employs 24dB octave state variable, Fourth order Linkwitz Riley filters that guarantee properly phased outputs at all frequencies which is optimal for the proper acoustic summing of common signals from adjacent drivers in the crossover region.