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This work presents an application of airborne source path contribution analysis with emphasis on prediction of wideband sounds inside a cabin from measurements made around a stand-alone engine. The heart of the method is a time domain source path receiver technique wherein the engine surface is modeled as a number of source points. Nearfield microphone measurements and transfer functions are used to quantify the source strengths at these points. This acoustic engine model is then used in combination with source-to-receiver transfer functions to calculate sound levels at other positions, such as at the driver's ear position. When combining all the data, the in-cabin engine sound can be synthesized even before the engine is physically installed into the vehicle. The method has been validated using a powertrain structure artificially excited by several shakers playing band-limited noise so as to produce a complicated vibration pattern on the surface.

An overview is presented of the overpressure and noise due to airbag deployment in a passenger car. Overpressure is the low frequency compression of the air in a closed compartment, and noise is the higher frequency sound of bag inflation. The overview is timely, because there is now an accumulation of medical evidence to indicate that the overpressure and noise resulting from airbag deployment can be a threat to hearing, while, at the same time, the growing use of multiple airbag systems increases the threat. This problem can be counteracted by using aspirating airbags that draw in air from the passenger compartment as they deploy. There are two types of aspirating bag: one using suction that requires a compartmentalized bag and the other using entrainment that does not require a compartmentalized bag. The relative merits of suction and entrainment are discussed in the paper. To date compartmentalized bags have not been used.