For decades vehicle acoustic insulation was all about weight and thickness of raw materials used. The transmission loss is directly linked to the mass per unit area: the heavier the better. Lightweight solutions were always linked to a loss in acoustic performance. Until now, no solution was available for this. It became even more of an issue with the transformation to electric mobility and the increasing demand for lightweight vehicles. . Electric vehicles offer the benefit of a quiet ride. This in turn increases the demand for even better acoustic insulation due to the lack of masking sound levels from the combustion engine.