I assume by arrays you mean a line array of direct radiators in a single box; keep in mind that a line array of horn loaded drivers is also possible. If you do mean a single box line array versus a single horn loaded box the line array will likely be a tall skinny box as opposed to a squat horn loaded box, and as such the line array will go to a lower frequency in the nearfield mode, while the shorter, wider horn will go to a lower frequency for the baffle step.