I’m not a speaker designer so I don’t know how much these differences actually make in dialogue intelligibility, but with the S2 oriented horizontally you no longer have the left and right sides of the cabinet rounded to reduce diffraction (now the top and bottom sides become the rounded sides). Since the RAAL ribbon tweeter has much more horizontal directivity and less vertical directivity, now you have a much different interaction between the tweeter and woofer when the two are side by side instead of one on top of the other. I guess the simple solution is to just test the difference but time to do stuff like this is limited with a newborn.

Maybe a question for Dave, but is the crossover of the Duo LCR higher than the crossover of the S2?