@erik_squires .."I thought this was a feature, not a limitation. AFAIK, the idea was to narrow the vertical dispersion to minimize floor and ceiling reflections as much as possible..".
I would agree with this assessment, and while I have tried other configurations where sound and stage went to the ceiling, what’s between my two MTM speakers now, and just to the outside of them on either side, the result produces amazing midrange and depth of stage. There is a cohesiveness in how the mids and high frequency blend together in a uniformed manner. Its just more engaging to me.
Seeing more MTM configurations surfacing (or resurfacing) in the past year than I recalled seeing in prior years. Was just thinking about this recently, wondering why some design engineers just rediscovered this. Some of my original attempts were to essentially mimic the original Proac Response 3 speakers from a few decades ago. A good friend still enjoys my first set. For my 3rd built attempt I decided to pull the drivers even closer together. Some rough test mule cabinets helped get there, until making the final cabinets out of Walnut ply. I like the result more this way for this added cohesion i’m hearing. Don’t think I could ever go back to 2-ways or TMM/TWW.