CD, the general principles, which should apply to the M60s, are that even speakers with good bass can be helped by setting them "small" and taking some of the load in the lowest bass off them(and the receiver). Besides the LFE channel itself which is sometimes present in movies, the sub would get most of the bass in all channels below the selected crossover point(generally 80Hz is suggested). The sub should be better at handling these frequencies and can be placed in an optimum position for bass(usually the corner)while a better position for the higher frequencies is some distance away from at least one wall. Letting the receiver handle the crossover and turning the sub crossover all the way up to get it out of the way also removes the step of trying to adjust crossovers to "blend" the sub with the other speakers.
