This invention presents a passive vibroacoustic device that serves the dual function of attenuating the vibration of a flexible structure, and providing acoustic dissipation to the volume or cavity enclosed by the structure. This reduces the transmission of sound from external sources into the enclosure, and reduces vibration of the structure. By design of the shunting resistor and the mass and suspension properties, the device can be optimized to achieve high levels of both structural vibration attenuation and acoustic attenuation. Incorporating a feedback loop or adaptation mechanism will permit the device to maintain optimum attenuation in the case of time varying systems.