The short answer to your first question is, "yes", and it's direct evidence of the TriPlanar's superior imaging (a function of its more stable azimuth, which produces lower crosstalk when properly adjusted).
A component that allows higher and more variable crosstalk (JMW) will produce fuzzier and less stable images across a broader listening zone than a component with lower and more stable crosstalk (TP). The TP sends better-differentiated information to each speaker (especially the tweeters) so smaller differences in listening position become more audible.
Speakers image differently, depending on their HF extension and phase coherency. We both have first order mid-tweeter Xovers and exceptional HF extension, so I'd expect great imaging from both our speakers.
Different speakers also produce different sized sweet spots, depending on their off-axis HF rolloff. I don't know about your ribbons but images change in my setup if I move my head L or R by just an inch. Soundstage depth and image integration are nearly as sensitive to fore/aft head movements. OTOH, our off-center listening seats have very indifferent imaging, or no imaging at all.
A component that allows higher and more variable crosstalk (JMW) will produce fuzzier and less stable images across a broader listening zone than a component with lower and more stable crosstalk (TP). The TP sends better-differentiated information to each speaker (especially the tweeters) so smaller differences in listening position become more audible.
With all the adjustments on the Tri to dial it in and using the Universe, should you expect a fantastic sweet spot with more fall off away from there?In my experience, yes to both questions - depending on the speakers.
Speakers image differently, depending on their HF extension and phase coherency. We both have first order mid-tweeter Xovers and exceptional HF extension, so I'd expect great imaging from both our speakers.
Different speakers also produce different sized sweet spots, depending on their off-axis HF rolloff. I don't know about your ribbons but images change in my setup if I move my head L or R by just an inch. Soundstage depth and image integration are nearly as sensitive to fore/aft head movements. OTOH, our off-center listening seats have very indifferent imaging, or no imaging at all.