Mike, I think that the onwall VP150 is too wide - i.e. it would extend across not only the center opening and the vertical rails, but into the openings on the sides. But I had not seriously considered that option, so I will measure for it. Thank you for the suggestion.

I know you guys want to make the round hole square so that it fits, but my goal is to get "something better than a VP100v2 that works in this configuration" not necessarily just "a better center channel".

bibere usque ad hilaritatem