A tuned mass system has a bulk mass acted upon by an excitation amplitude and a reaction mass coupled to the bulk mass. A resistance-to-motion controlled coupling mechanism associated with the reaction mass is configured to proportionally modulate independent of excitation force such that the relative phase of the bulk mass and the reaction mass is substantially constant throughout an extended range of excitation amplitude. The resistance-to-motion controlled coupling mechanism is a Variable Aperture Reciprocating Reed (VARR) Valve in one embodiment, and operates as a passive mechanism. In other embodiments, active resistance-to-motion controlled coupling mechanisms are employed.