But remember, this will change the units HF behaviour - the gluing solution I mean! But as far as I recall, you cross-over pretty low, so I doubt it will be a problem - but you do need to know how much mass is needed. And don't forget, the overall efficiency of the driver will be reduced - the usual battle between LF extension & efficiency.

Having not tried the trick with gluing added mass to the centerdome myself, I hope somebody else will chime in about experiences in this regard. Oh & I need to remind you, gluing things to the drivers centerdome will increase it's moving mass, but NOT it's re-sale value ;-)