When I looked at the photo at the beginning of this thread, I thought to myself, well, you do have your VP150 kind of buried in that equipment stand. I think interference and boundary effects from the neighboring equipment might well affect the lateral dispersion of the VP150. Following up kcarlile's comment, try pulling the center out a bit and see if it improves anything.
All speakers function better in free space. This, of course, makes placement of center channel speakers a real pain in the butt. In my own case, when I placed a VP150 in the equipment stand below my flat screen, I hated the sound. Moving it to a metal shelf supported by the TV reduced coloration and improved intelligibility.
And no, with all the talk of using an M2 as a center, which I've tried, it will not keep up with the M80s at higher SPL levels and may sound strained. After all, the 150 has five drivers and the M2 just two. At higher playback levels, the VP150 is much better equipped to deliver clean, high-volume dialog.
For aesthetic reasons, I doubt you'll want to move your center to less-encumbered placement above the screen or stand. There might be an arrangement of dual M2s that could work for you. I'll think about it.
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