Abstract: A multifunctional, lightweight and acoustically optimized interior lining for the roof of a vehicle is disclosed. The inventive lining comprises an air permeable core layer, a first stiffening layer, a second stiffening layer and a decor layer. Said layers are connected to one another by means of air permeable adhesive layers. The total air flow resistance of the second stiffening layer, decor layer, and attached adhesive layers, arranged on the side of the core layer facing the passenger compartment, is within the range of 500 Nsm?3>Rt<3500 Nsm?3. The total surface area weight of said layers lies in the range of 300 to 800 gr/m2. A method for producing said lining and the use thereof in a roof of a vehicle are also disclosed.

Abstract: The invention concerns a heating, ventilating and/or air conditioning device comprising at least an air distribution channel having a downstream end, and at least an air diffusing element arranged at said one downstream end. The invention is characterized in that the air diffusing element (1) comprises a support (11) provided with through orifices (17) and covered over at least one of its faces with a material (12, 16), having air resistance ranged between 10 N.s.m−3 and 180 N.s.m−3.