Measurements are 2 meter, 60 degrees off axis, in room.

1/24th octave graph

1/3rd octave graph

Unusually smooth off-axis response, especially for a horizontally configured center. Thanks, Craig.

You are welcome, of course ... and Kudos to Jack for the links !

Interesting, informative and correct measurements - thanks Craig. Makes one wonder out loud, as I am doing, how this kind of measurement would enable a speaker trigger any negative off-axis critcisms.

Always an interesting question ... When dealing with sound, people are often surprised at how "high" certain notes are ... most people will consider a 1000 Hz note to be "treble" ... and a 10,000 Hz note is REALLY high.

I could easily see how, at 4000 Hz, a room interaction combined with the inherent "peak" in the VP-150 could cause a feeling of "screechy treble" ...

Then there is the placebo effect ... we read something about, say, metal drivers ... next thing, we are HEARING what we read ... blind tests tend to fiz that ... more later, someone is ready to go to dinner ...

"Then there is the placebo effect ... we read something about, say, metal drivers ... next thing, we are HEARING what we read"

I would say that is a HUGE part of it.
We play head games with ourselves, like it or not.