An acoustic dampening panel comprising: (a) a first layer of expanded polypropylene; (b) a solid layer having a surface weight between 2.4 kilograms per meter squared and 25 kilograms per meter squared; and, (c) a second layer of expanded polypropylene, where the first and second layers of expanded polypropylene sandwich the solid layer therebetween. The acoustic dampening panel may further comprise a fourth layer comprising a metal skin, where the solid layer and the metal skin sandwich the second layer therebetween.