Eq the 2khz hump down (like most of the series) and you have a really great headphone! Comparing the K601 direct with the K612 reveals the 'improvements' that have been made both in the treble and slightly warmer bass.
I always felt that the K601 was a bargain that was overshadowed by the K701, but the K612 is even nicer.
Throw on some K702 pads and it tames the treble a bit... at the expense of some detail/imaging, of course. You also get spme slight bass imrovement, as well...
Warning: Spoiler! (Click to show)