An appropriate amount of damping is a pre-requisite for achieving effective vibration control and isolation of dynamic structures. In this work, a tunable electromagnetic shunt damper with opposing magnet pairs configuration is proposed to provide adjustable damping for structural vibration control applications. The proposed opposing magnet pair arrangement is shown to enable significant increase in the tunable range of the damper. Both simulations and experiments are conducted to verify the improvement of the proposed design. Tests on displacement transmissibility in single and two degree-of-freedom systems also confirm the fine tunability of the proposed damper to achieve ultimate vibration reductions. The vibration amplitudes in both cases are suppressed significantly by the proposed tunable damper in the whole frequency range of the experiments. The proposed tunable electromagnetic damper is also applied to a dynamic vibration absorber with its H∞ optimum damping achieved experimentally by following a proper tuning procedure described in the paper.