Hello Tomtuttle,
Quick answer from the man who designed them (Ian): "Only the cabinet, port system, and x-overs are different. The sound is the same but the SPL at 1w/1m is down 1 - 2 db on the W series."
On the basis of my early listening tests to the prototypes, I agree that the sound compared to the boxy brethren is tonally virtually indistinguishable, or, "similarly good."
That was our goal--to make an in-wall/on-wall hybrid that did not compromise sound quality, and which was consistent no matter what wall you installed it in, hence the self-contained, tuned enclosure and the cunning ports (on the ported models).
There will be more detail in the upcoming Axiom AudioFile newsletter in an interview with Ian on the design process for the W series.
Regards,
