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The goal of the present study is to provide a simple method to compare structure borne noise sources in order to choose the most efficient one, considering the transmission of dynamic forces. It is well known that mechanical sources are not only dependent of the source itself but also of the receiving structure, in addition real sources cannot be reduced to a transverse force acting on the structure but more complicated effect like moment excitation must be taken into account. The advantage of the reception plate method is to characterize the source globally by the level of vibration of the reception plate whatever the type of excitation, the idea is basically to characterize mechanical sources as it is done for acoustical sources in reverberant rooms. A reception plate test bench has been developed to determine the power injected by mechanical sources. Two prototype plates have been designed in order to have different receiving mobilities.

The control of sound fields radiated by vibrating structures in a passenger compartment, (especially structures connected to different organs like the engine powertrain, the fan motor unit, seats, the steering column, electrical motors more and more, etc.) is among the functions of the automotive manufacturers. The absence of physical prototypes in the development phase systems led OEMs1 to use tests results obtained on benches following technical specifications from manufacturers. The transition "bench to vehicle" for vibro- acoustic behaviour sets many challenges that this standard intends to clear up. This standard specifies the experimental method to transpose the dynamic forces generated by the global movements of an active component between the vehicle and a test bench. The efforts are first measured on test benches and then transposed from test bench towards the vehicle. The standard is now a French standard (XP R 19-701) and is submitted to ISO process [1].

The new requirements during the first stages of the conception of a HVAC prompt the designer to integrate the acoustic problematic increasingly upstream. The designer needs to select a coherent components’ choice in order to comply with the specifications in terms of aeraulic and acoustic performances. A tool has been created to guide the designer’s choices based on an acoustic synthesis which is a design and/or diagnosis approach used to analyze and predict the acoustic behavior of a complex system. The synthesis is developed in order to propose an approach which considers the integration effects and some interaction effects. The acoustic synthesis results are the starting point of a psycho-acoustic study providing audio samples of the prediction and indications of the HVAC acceptance by the prospective user. Also, one may compare the results of different acoustic synthesis projects to study the influence of the parameters on the acoustic prediction.