Early reflections dominate in small rooms as per Dr. Floyd Toole's extensive research. Of course a speaker exhibiting a smooth and even power response will also likely produce good early reflections since its off axis response is consistent.
From my conversation with him on the topic. The direct sound dominates. Flat off axis happens only with flat on-axis and so off-axis is the *second* trait.
We also discussed anechoic chambers, surround sound, and the impacts of those (it really was a short discussion), and consensus was that a matrix of speakers in an anechoic chamber was the ideal; but not realistic.
Of course, I also experimented directly with this. Wmax was a big advocate of controlled off-axis response, and I purchased a pair of hand-built speakers from him to investigate that claim. (still have them). They are also dynamic crossovers (to tie back to the topic of the thread) and 4-way sealed.
And I have Toole's book, and took the listening training.
My take away from the whole thing? *Avoiding* bad off-axis output is the goal. Definitely in a surround system (and I would argue in a prime-seating position stereo); no off-axis is ideal; but where there is off-axis (and it's nearly unavoidable), and where there are reflections, they need to be as flat as possible.
For an accessible example of no-reflection and no-off-axis listening: I recommend headphones.
