Improved Noise Source Identification Using Sound Quality Metrics Mapping in Vehicle Noise Measurements

A method of mapping a sound field using sound quality metrics has been investigated with an aim of identifying noise sources based on their sound characters rather than traditional measures such as sound pressure level (SPL) and intensity. The method having 11 metrics was implemented in four different array applications, namely near-field acoustical holography, planar beamforming, spherical beamforming, and patch acoustical holography. The sound quality metrics (SQ) mapping was applied to diesel engine measurements as well as vehicle interior measurements. In both applications, there have been a number of attempts to identify impulsive noise sources and therefore in this investigation an impulsiveness metric was developed. The proposed metric was validated against ideal impulses as a function of impulse repetition frequency, amplitude and duration of impulses. The results of noise source identification in both applications revealed that the proposed impulsiveness mapping enabled the detection of impulsive or rattling sources to be more effective compared to the use of SPL and intensity. Furthermore, a number of potential improvements on the SQ mapping are discussed.