Methods for transfer path analysis

Transfer path analysis (TPA) is a well known technique to evaluate and to separate the different transfer paths describing how noise gets from the sources into the compartment of a passenger car, i.e. to the driver's ear. It is not only a measurement technique but a prediction method as well. Based on previous measurements and assumptions TPA provides the opportunity to predict the interior sound for a virtual prototype. Due to the progress in computational technology and measurement techniques, TPA is being seen as an important tool in automotive acoustic design. The paper gives a brief survey of the mathematical background of different TPA methods like the complex stiffness method or the inertance matrix method. With the help of a 3:1 scaled simplified car model differences between the methods of calculation are verified and discussed. In conclusion the paper presents the measurement setup for a real car with a dominating transfer path of the structure borne engine noise into the passenger compartment.