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Acoustic Diagnostic Network Algorithms (DNA) are experimental methods that extract airborne acoustic characteristics from a motor vehicle and decompose this information into a set of networks from which the source, path and receiver noise sources and paths can be determined. Unlike traditional transfer path analysis Acoustic DNA takes the problem into the fine detail. It answers questions such as what, where and how does a vehicle's acoustic systems need to be changed in order to achieve any given objective. This paper describes the fundamental methodology and features together with how it has been implemented into a computer program that has been used successfully in over 50 vehicle projects within the Authors Research and Development group on a wide range of motor vehicles.

Worldwide OEM's are seeking for potential to further reduce noise & CO2 pollution. Especially the European premium class vehicles are basically all equipped with aerodynamic under-shields in order to reduce the air drag coefficient, and hence to lower fuel consumption and CO2 emission. The complete absorptive vehicle underbody approach has proved to be a promising noise abatement strategy. First, it leads to substantial exterior and interior noise improvements and also to a reduction of the disturbing cold start Diesel engine noise in the neighborhood. Second, it bears significant potential for further weight reduction. The absorptive underbody treatments were first developed in the virtual environment of Statistical Energy Analysis (SEA), where each component is specified according to its acoustic characteristics, namely its airflow Resistivity.