After thinking about for a bit I think I understand the problem a bit more. While same frequencies played in an array can cancel or reinforce (even double the magnitude) each other at certain angles, multiples of those frequencies can cancel or reinforce individual waves of its multiple. IE, a 100Hz signal could reduce or reinforce every other wave in a 200Hz signal. Thinking a bit more, this situation can happen not just on the array plane, but every plane not perpendicular to the array. That's it, I'm done. My head hurts.
