I see, well my goal is not to hear about parent translations from a child object, anyway, that was just a means to the goal.
My goal is simply to be tipped of when an object gets translated so I can check what that translation is. From your response, extending Object3D and overriding the "translate" methods would not help me anyway, because if my object were to be a child of another object which gets translated, My object would not know about it. (Besides, doing an extension of Object3D would not be practical for what I am doing, anyway - this is related to creating a method for binding a sound source to an Object3D. It is for a library that will be used by multiple users and different applications ).
So to achieve my goal, I will have to approach this problem from a different angle. I think I will create a method that gets called from the main game loop, which calls "getTransformedCenter()" on the object in question to determine if a translation has taken place and what that translation is.
Thanks for the advice!