Gotta say, mightily dissapointed with these...
I originally bought a pair of DT770's, in an attempt to find the perfect companion to 'rock out' with. My other cans are great for classical, jazz, but I miss the bass-slam that a good pair of closed-backs can give you.
I was actually pretty happy with the 770's. And still am. They have a great listenable character, but compared to my other cans they can sound a bit 'rough around the edges'.
I thought the DT1770's would be the perfect solution. Compared to the 770's they are a little (and I MEAN a little) more refined, but IMO at least, they do not pull away from the 770's enough to make them worth the while, never mind four-times the price.
This makes the DT700's one of the greatest over-achievers of the century IMO, and makes the DT1770's one of the biggest dissapointments...