US Patent 7743880 Sound absorbing structure

A sound absorbing structure includes a housing having a front face, and a side face which is provided perpendicularly around at least a part of an edge portion of the front face; a gas adsorption material for physically adsorbing gas in an interior space delimited by the front face and the side face of the housing, which gas adsorption material is placed in the interior space; sealing element for sealing the gas adsorption material from outside thereof; and an acoustic connection section for functioning as an acoustic mass so as to acoustically connect an exterior space and the interior space of the housing, which acoustic connection section is provided in at least one of the front face and the side face.