Patent ID: 7789197

Claim:
Soundproofing assembly comprising superimposed layers, of the type which includes: a first layer ( 36 ) having a good resistance to the passage of air, and a second layer, the second layer comprised of a group ( 24 ) of layers having a mass-spring function, the second group including a layer ( 28 ) functioning as a viscoelastic heavy mass and a layer ( 26 ) of the spring type, wherein, the first layer comprises a layer ( 36 ) of open-cell foam having high porosity, high tortuosity and a good resistance to the passage of air, this high tortuosity layer ( 36 ) having, due to its high tortuosity, excellent sound absorption properties at medium and high frequencies, the soundproofing defines an automobile passenger compartment soundproofing, the first layer ( 36 ) comprises only a single layer ( 36 ) of foam with high tortuosity, a first side of the first layer ( 36 ) is in direct contact with the layer ( 28 ) functioning as a viscoelastic heavy mass, and a second side of the first layer ( 36 ) is uncovered and exposed.