I was in the Sony Store in London yesterday and noticed this display of Sony's flagship XBA4's. They claim that each driver is for a different frequency (Highs, mids, bass, super bass). Funny thing is that all four drivers look identical, there's no crossover circuitry and only one acoustic filter. Tried to get a better shot of the drivers to try and ID them but the staff started giving me odd looks.
Aye, that's Londoners for you - they're s suspicious bunch - I should know, I spent the first 15 years or so of my life there!