Dave, the M22 crossover is at 2.7 KHz, compared to 2.0 KHz on the Monitors. The idea is to set the crossover high enough so that the tweeter's power handling capacity isn't strained by making it handle a too low frequency range. Equally important is setting it low enough so that the midwoofer doesn't have to handle a higher frequency range where it wouldn't have good dispersion. Since the Monitor midwoofers have bigger cones(the bigger the cone, the sooner its dispersion begins to narrow)they need a lower crossover to have wide dispersion of the frequencies near the crossover point. So, it's just a balancing of the midwoofer size vs the tweeter size.
