Sound absorption describes the conversion of sound energy into heat. Materials featuring high sound absorption are excellently suited to sound insulation in construction or the automotive industry. Fibrous components such as nonwovens commend themselves to these applications owing to their porous structure. Fine fibres create a more or less flexible “fibre skeleton“, featuring a large inner surface. Sound is diffracted in numerous places, whereby sound waves are absorbed and dampened by the nonwoven. Their structure also makes nonwovens an ideal heat insulator.
Properties such as the material’s thickness, density, porousness and flow resistance determine the level of absorption. The measurement of sound absorption under random incidence is carried out in a reverberation room according to DIN EN ISO 354, or in a smaller alpha cabin. Sound absorption under vertical sound incidence can be determined according to DIN EN ISO 10534 in a Kundt's tube, or impedance tube. Sandler nonwovens are tested for their sound absorption properties in cooperation with external institutes.
Together with renowned partners from research and the automotive industry, Sandler developed a simulation tool, enabling the calculation of the required absorption level. New variants and products can be computer-simulated based on the required absorption profiles before the first trial production is undertaken. In this way, time and costs are saved and valuable resources conserved.
See also: Air-permeability