They arrived and I must say, I'm really chuffed with them. I enjoyed the K601 a great deal and was curious as to what has been done to the K612.
I feel that there are 'improvements' but they are quite slight. The bass seems more present and the treble slightly less edgy. (I'm not sure whether the slightly raised bass makes the treble 'seem' lower)
I changed the pads to K702 pads since they are a bit deeper and angled. Some have claimed that this raises the bass. I didn't notice in particular whether it did, but the bass is really well balanced with the rest of the spectrum and I love the detail that you can hear down there. The sound of bass guitars has a lovely 'rubber band' tone instead of a tuned 'thud' which I really do like.
Only slight cosmetic changes - cable is a bit thinner and more flexible. A plug that adapts for large/small jack sockets. Dark pads. (Maybe different material) the headphone looks a bit sleeker with its new colours.
In the UK, these can be bought for £115 - £130 which for the sound that you get is excellent. I must admit, this has made me more curious about the K712 which I heard yesterday and really liked as well.
No one seen a FR plot for the K612?