That is Panasonic's "bi-amp" feature. The speakers don't have crossovers built into them. The Panasonic head unit (the system the speakers where intended to be used with) has the crossovers for the speakers inside it. The speakers are powered by the same amplifier channel in the head unit, but a crossover is used. Connecting the Panasonic speakers to a home theater or stereo receiver is not a good idea. Panasonic sound system speakers are typically 6 ohms. I may be incorrect here, but I think the impedance would increase to 12 ohms if connected the the receiver.