No, Maj; the lower you set the crossover(in the receiver; the frequency control on the sub should be moved out of the way by setting it to its highest setting)the less that the sub has to do. A small setting for the mains with an 80Hz crossover is a good compromise number; 80Hz is high enough to take a significant amount of the low bass load off the mains and give it to the sub which handles it best, and low enough so that the sub isn't easily localizable.

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Enjoy the music, not the equipment.