You mostly see this type of design in pro-audio where the pole piece and woofer are used as a wave-guide,
like so. I believe Tannoy uses similar designs for their home audio speakers. It isn't new, but it can be tricky to pull off for a hi-fi speaker. Dr. Hsu and Don Keele is a hell of a team up though, so I have a good feeling about these.
The KEF concentric designs are quite different, but, of course, their design approach addresses many of the same problems.