Abstract: A sound insulation device (D) includes at least three layers: a first layer (1), facing a sound source to be blocked, comprising a blackout cloth with a weight greater than 250 g/m2, a second layer (2) including a metalized cloth, a metalized face (2a) of the cloth being disposed in contact with the first layer, a third layer (3) including a brushed cotton cloth having a weight greater than 250 g/m2, disposed in contact with the second layer (2) on the side opposite the first layer (1), the metalized cloth being produced by in vacuo metallization of a woven substrate previously calendered by the application of a compression force.