IFMU, thanks for reminding me about that discussion...
I'm not sure whether the long term intention of "active vibration control" in X2 is simply the Moog eccentric weight type (as fitted to S-92), or the type that is generally known as Higher Harmonic Control. Higher harmonic control would be suited to a fast reacting FBW system, and offers the advantages mentioned. It may be that the Moog eccentric weight system will be fitted with the soon-to-fly hydraulic FBW, but i would be suprised if development stopped here. Part of the long term objective of fully electric FBW might be to fit direct blade vibration control, such as this system being developed at ONERA:
http://www.onera.fr/zoominthelab/17-helicopters.php
To make further progress in developing a silent and comfotable helicopter, "active" solutions need to be found, solutions where the angle of incidence of the blades can be modified. In effect, during rotation, the blades do not experience the same effects when they move in the same direction as the helicopter (advancing blade) as when their movement is in the other direction (retreating blade). Transonic flows may appear at the end of an advancing blade, whereas separated flows appear on a retreating blade and may cause the rotor to stall. In an active governor rotor, it is possible to vary local lift optimally with the help of trailing edge flaps etc. The objective is that the vortices are less intense and pass further away from the following blade. The increase in lift plays a critical role: when the lift is stronger as the vortices get closer then they are pushed further down and make less noise. This effect has been confirmed by calculations and in the wind-tunnel. Other parts of the helicopter may be made active, like the horizontal tail wing (ensuring the stability of the machine and controlling its attitude) or the vertical fin. But work on these aspects is less well advanced.
Development status given here:
http://www.dlr.de/fa/Portaldata/17/R...nschneider.pdf