Z, it is in fact a "design issue", but certainly not one unique to Axiom. Vertically configured driver arrays give wider and smoother horizontal response than does a horizontal array. Flip that MTM up on end and listen to the improved dispersion. Again, if there's room for it, a vertical center speaker as similar to(or identical to)the mains as possible should be considered. If there isn't room, you use what fits(or use no center speaker at all).

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Enjoy the music, not the equipment.