Wait...doesn't the D600 look similar?
Okay, now that you think about it, the D600 does have a more professional, baby-flagship look going on (its shape is similar to the D7100).
The Urban Raver line looks downright crazy; plus, they're marketed as a "street and club-goer" series. Who in the hell would want to wear those at a club?
DEM BULGES...
Still, I don't like the headband shape of all of the new over-ear models; that is, only when viewed from an angle as shown in the D600 picture (left).
And...they're massive. I saw them on the head of a seller online, and boy, it was big. Compared to my Beats, these are actually larger, though probably lighter.
Oh yeah, and kimvictor, it's pentagonal, not hexagonal. Denon's website said so.
EDIT: After taking a look at the Denon website, the bulges of the D400 actually house controls, with teh left used to light up a few LEDs and the right one controlling your music (pause/play, next/previous track) and even answer calls with a microphone.
Also, I found this from the D400 page:
If you bring them about, they'll ask you that question, with much surprise, just as Denon said. Maybe it's because it looks crazy. Well, at least Denon acknowledges its outrageous design of the D400. Everything else in their new line seems okay, though.