A noise attenuating trim part for a vehicle, with acoustic mass-spring characteristics comprising a mass layer comprising at least an impervious barrier layer, and a decoupling layer consisting of open cell foam and wherein the decoupling layer has a first surface adjacent to the mass layer and a second surface facing away from the mass layer, and wherein the decoupling layer and mass layer are laminated together and wherein the decoupling layer has at least one region with a plurality of indentations wherein each indentation comprises a round base area wherein the round base areas are situated in plane with the second surface and wherein the total surface area of the round base areas is between 10 and 40% of the total surface area of the second surface of the decoupling layer.