I get your point. I do.
But to get a truly full-range passive speaker (let's arbitrarily say something that plays flat to 40Hz or so), you need not only a bigger driver but also a much bigger box. Axiom already makes full-range towers, and I'm sure if they could somehow bend the laws of physics to make them smaller, they would, as doing so could dramatically reduce their production and shipping costs.
So, I guess my question is, how much deeper than an M22 do you want this thing to go, or what do you want it to do that an M22 doesn't do? The M22 is Axiom's "big bookshelf" speaker, and I'm comfortable that it articulates Ian's design philosophy, which emphasizes off-axis response and low distortion.
As to a powered M2/EP400 in-one-box thing - again, look at the volume of the enclosure. Also, it's worth noting that the optimal placement for the transducers producing 80Hz and up is very rarely the optimal placement for the transducers producing lower frequencies. Since "The Room" is such an important component, you really get much greater flexibility by NOT having everything in one box.
Finally, some of the very best speakers I've ever heard are two-way designs.
I guess my point is, I'm sure Ian has already considered a bookshelf three-way for Axiom. So, I wouldn't hold your breath. No matter how much sense we might think it makes, the science and production are undoubtedly much more complicated.
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