Mike, as you may recall I've suggested use of the phantom center several times here and use it myself in appropriate situations. As far as I'm concerned there is no disadvantage other than the shift of the centered image when the listener moves left or right. The fear of additional "comb filtering" when the same sound is reproduced from two speakers and the listener isn't centered isn't justified in my experience. Comb filtering goes on all over the place in any live listening room.

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Enjoy the music, not the equipment.