In the process of determining optimal treatment locations and compositions for automotive noise control parts, it is necessary to know both low frequency and high frequency sound contributions of automotive interior sheet metal panels. Several techniques of experimentally assessing individual panel contributions to coherent, low frequency noise as well as incoherent, high frequency noise are investigated. These include use of a sound intensity probe, a pressure gradient microphone and an accelerometer for measurement of panel vibrations. Acoustical insulation of all interior surfaces except a particular surface of interest (the “windowing” method) and boundary element modeling (for exclusively low frequency characterization) are also investigated. While no one technique is ideally suited to determining contributions in the entire audible frequency range, the boundary element method was found to be particularly useful for coherent source characterization, while the more traditional “windowing” method is well-suited to incoherent source characterization.