If the K7XX have a +3db bass, they're more likely to be a chinese version of the K712 qnd not the annies... I own both the K702/65th and the K712 pro, and when I compared them with an older K701, i did notice more bass on both units, however, the increased bass on the K712 was more noticeable, not a lot more anyway... I doo think there is slightly more bass in the K712 than on the K702/65th... But difference is not easily noticeable.
By the way, I dont remember seen a 3db increase on any official comunication made by AKG or in the tech sheets for the K702 Anniversary Edition... The 3db increase was a statement used to advertise the K712.
Qnyway, if they weere not made in china, maybe I'll give them a try... When they are relased please let us know your opinions ¿Are they really another K702/65th or AKG fool you to buy an standard k702 with annie pads? ¿Are they K712 made in china? ¿Are they a totally different set of headphones?