Yes TNT, in my pre-Axiom setup I use a small vertical speaker(most similar to an M2) identical to the mains for the center. When I have the center turned on(rather than just using the mains to create a "phantom" center)it works quite well and in my view has smoother horizontal dispersion than a horizontally configured center(haven't heard VP100 or VP150).

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Enjoy the music, not the equipment.