Acoustic foam decoupler

A noise attenuating trim part for a vehicle, with acoustic mass-spring characteristics, comprising:

• a mass layer having an impervious barrier layer;
• a decoupling layer comprising open cell foam, the decoupling layer having a first surface laminated to the mass layer and a second surface facing away from the mass layer and adapted for interconnection to a vehicle body, wherein the second surface includes
• at least one region with a plurality of indentations, and
• wherein each indentation is defined by a geometric shape bounded by a generally round base area that corresponds with the second surface, such that the entirety of the round base areas are configured to contact the vehicle body and the geometric shapes define cavities between the decoupling layer and the vehicle body;
• wherein the total surface area of the generally round base areas is between 10 and 40% of the total surface area of the second surface of the decoupling layer;
• and
• wherein a shortest distance (D) between two indentations is more than 4 mm.