All speakers 2Ω MinBridged 4Ω Min13Bridged 4Ω MinST-4X SQ Speaker Wiring4Ch ModeIf using coaxial speakers, consider usingthe HP filters at the lowest setting to keepdeep bass from damaging the speakers asa crossover and maintain correct.High Power 2Ch ModeSimilar to bridging a stereo amp to a mono woofer, you can use the 4-Ch amp in adual mono mode to create (in this case) a stereo amp with 190 watts RMS/ch.As with any bridged setup the speakers must be a minimum of 4Ω impedance.If you are using the active crossovers you should be sure that they are set to thesame frequencyHigh power stereo using dual mono bridgehookups requires that the speakers be aminimun of 4 Ohms impedance each.