Yes, going simply by the Axiom spec, a 100Hz crossover would appear to be advisable. However, the amount of room reinforcement in a particular location can result in a greater extension than the spec suggests. Measurements from one of the auto calibration systems or a separate SPL meter can help answer this question.

In any case, the term "danger" wouldn't seem to really apply; the worst result would be a slight weakness in the 80-90Hz area.

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Enjoy the music, not the equipment.