I had the follow up model, the AR9ls.
Loved that speaker, ultimately taken by foam rot. The changes were moving the woofers to the front, a 12" forward facing driver with a 10" down facing driver that fired into a " bass contour chamber", whatever that really is. The other improvement was mounting the upper midrange and tweeter on a common plate, significantly reducing the center to center spacing which helps with vertical polar response.
Never heard then side by side, so hard to assess which was "better", but my in room response extended to 20Hz easily.
I think one of the things the new design did was perform better when freestanding. Like the Allison speakers, the original AR9 was designed to work up against the wall for best performance.
AR was a great company, I am still using my "The AR Turntable" with Grace 714 unipivot Tonearm today when I pull out the vynil......