In reply to:
Horizontal layouts don't work for center speakers either, unless the drivers are arranged symmetrically (eg. the WTW array,
Umm, a bit of a stretch Bridgman as it does not explain the VP150.
Ian has done so
here and
here .
Lobing is not always a big consequence as some believe and in regards to centre speakers, those who say it is a huge problem typically state this after they have heard it from sitting so far off axis that it makes you wonder about what they are expecting for performance from a system. Complete perfect sound dispersion 360 degrees behind and in front of each speaker? I sometimes wonder.