Acoustic Cavity Characteristics in Relation to Multiple Excitation Sources

This paper presents an experimental method for analyzing the acoustical characteristics of enclosed cavities with respect to multiple coherent noise sources. The method is based on the application of a Multiple Input/Two Output frequency domain model. The model outputs are the sound pressure signals from two closely spaced microphones while the model inputs are characteristics from the candidate noise sources. The emphasis of this paper is on the implementation and interpretation of the method results in a simulated laboratory environment. First, the theory behind this method is briefly reviewed. Next, the method is applied to a three dimensional rectangular cavity with two coherent cavity excitation sources. A complete analysis of the cavity is performed which includes the determination of the following acoustic characteristics: 1) identification and ranking of the multiple noise sources, 2) identification of the cavity acoustic particle accelerance mode shapes and ranking of the modal excitation sources. The study concentrates on the application of the method and the interpretation of the model estimated acoustic quantities to obtain meaningful results.