I'm getting the K7XX in a couple of days so will make comparisons then. The K7XX is meant to be based on the 65th Annies but the later model(K712 pads) Now the 65th Annie with K712 pads is, from my personal tests, the Q701 with the memory foam pads. The Q701 suffered in a minor way from the upper mid peak while the K701, K702 had it very obviously.
The K712 has an even bigger boost to that peak giving vocals a shouty effect in that region that my ears hated.
The Q701 with the K712 pads(Newer Annie, possible K7XX) plus the K712 foam which has less pockets sounded close to the Original Annie but more airy, spacious and less intimate. It was overall a better version of the original Annie(Small pads) as it had a better soundstage and was less congested. I actually preferred the old Annie as I like intimacy but performance wise the newer Annie is superior.
The newer Annie vs the K712 is something I can help you with until I can confirm the K7XX sounds the same as the newer Annie
The K712 is a dryer sounding headphone that is bright. The newer Annie is neutral, less bright and again like the Q701 suffers in a minor way from the peak. Bass on the K712 was slight more present but I'm splitting hairs. The Newer Annie had more forward, present mids with a smaller soundstage. K712's mids are more pushed back as the headphone is more spacious than the Annie. Imaging is the same on both I didn't notice anything apart from the soundstage difference.
I shall confirm later if the K7XX is identical like Massdrop said to the Annie.
Hope this slightly helps.