Measurement of sound absorption coefficients on the automotive isolation materials and determining the optimum material thickness

Interior noise levels have a high effect for today?s customers during choosingtheir new cars. Today automotive OEMs and suppliers noticed this propertyand recently give more attention on increasing the sound quality of producedvehicles. Current needs and the competition between automotive OEMs forcesthe producers to produce better isolation solutions.To characterize the isolation effect or isolators several ways can be used. In thisstudy, sound absorption coefficients of five different isolators which consistdifferent materials with the same thickness have been tested with an ?AcousticImpedance Tube?. In addition to this test the effect of the material thickness isinvestigated.Acquired results have been compared according to isolator material properties;also the effect of the isolator type on the internal noise levels is investigated.