An ear pad for earphones comprises a foam-like material formed into a pad enclosing the user's ear in use in order to expand the essentially linear frequency response of a good earphone so that it brings also the lowest still audible frequencies into the linear region, and simultaneously with the expansion...http://www.google.es/patents/US4809811?utm_source=gb-gplus-sharePatente US4809811 - Ear pad construction for earphones
