Vertical mounting of course doesn't eliminate the crossover-related off-axis lobing, but it places it entirely on the vertical axis . . . and the vertical-axis listening position in the control room varies far less than the horizontal.
Kirkus,
Good point. I agree tha this is an interesting discussion. Thx to you and to Kilopop and others.
However I woudl add that your point above is even more a problem for passive designs.
I would add that the advantage of Active speakers is that you can make a much sharper and phase compensated crossover filter precisely because it is active. This should reduce lobing. From what I know the 1038's allow the HF/MF combined unit to be rotated inside the cabinet for horizontal placement and this should ensure that any remaining lobing remains in the vertical axis where it is less significant.

