A Rapid Method to Rank Sound Sources in a Reverberant Environment

Sound generated by an engine is one of the major contributors to an automobile’s overall sound pressure level (SPL). During its development, the engine’s SPL is monitored frequently for compliance. If the SPL is found to be exceeded, sources are identified for modification. As the timeline is critical, a rapid methodology is required to reduce it. The proposed methodology employs dynamic mode decomposition (DMD), a data-driven approach for source ranking. DMD detects changes in a variable between two successive time intervals and quantifies its rate of change. Based on the physics involved, a new interpretation for DMD’s decay factor is introduced to capture the sound signal’s nature. DMD and Short-Time Fourier Transform (STFT) are compared in this study. The STFT-based systems employ a large array of microphones to rank the sources. In this study, a single microphone and DMD are used to rank the sources. DMD utilizes far less data than the conventional STFT for source identification and ranking. Though DMD requires more memory and time than STFT, the overall time to complete the ranking of sources is very short. The results are compared with calculated values and show a negligible discrepancy between them.