Thanks to Gelocks for sending these out!
These are one of Sony's current premium cans. According to the literature these can go up to 100 kHz. I have no way to verify this, but if true I guess these are "fast". Drivers appear to be angled. On thing about these cans is that they are fairly comfortable and light. Marv's ears might fit inside. Not bad looking either.
As far as sound, these are warm and overall fairly well behaved. I like the balance of these. Bass goes deep, but not very detailed. Mids are fairly even and clean. Treble is good, but it does have some edge to it. However, I doesn't really bother me. While bass carries good impact and presence, it does not muddy up the sound too much.
Over all these are among the best Sony cans I've heard, and among the most comfy closed cans I've put on my head across the board.
Senn HD630VB might have a tough time doing better than these based on what I've seen and read so far. Cable is detachable for one. IMO these look a lot better too.
Comparos (HD600 and ADP)