Active and passive noise reduction control techniques are used to reduce and/or control vibrations and accompanying sound radiation in vibrating bodies. In many instances, active noise reduction techniques are costly and involve complex control systems; passive noise reduction techniques are often bulky and not as effective. This novel invention provides a distributed active vibration absorber, and a distributed passive vibration absorber, to effectively control vibration and acoustic sound using an elastic layer of thermal or insulation material in which a plurality of discrete masses are distributed throughout.
This inventive blanket offers an improved alternative to melamine/polyurethane foams conventionally used for commercial and industrial noise control. Advantageously, HG blankets serve multiple purposes, including but not limited to, reducing structure-borne vibrations, providing transmission loss, and reducing reverberation. In a further embodiment, this novel noise reduction technique can be implemented inside the wall or ceiling structures of homes or commercial buildings, inside the housing of industrial machinery or other equipment, or inside doors, wing, or other parts of vehicles to properly create an acoustic barrier. Additionally, this invention allows easy installation, in which the insulation material and distributed masses can be blown into position in the wall or ceiling structures, or other structures as mentioned above.