Spatial sound quality estimation with array techniques

 

Instrumental sound quality analysis has been widely used as a major methodology to detect target sounds, e.g. annoying sources, emanating from the test object. Furthermore, the array techniques, such as beamforming and non-stationary spatial transformation of sound fields (NS-STSF), have been employed to localize and rank individual sound sources as a function of sound pressure, intensity, and particle velocity. But the localization of the target sounds needs a lot of engineering efforts as a result of the complicated relationship between the two technologies: sound quality analysis and array techniques. In an initial study, a loudness and sharpness mapping is being developed using beamforming. A 42-channel microphone array was set up to measure simulated sources generated by two loudspeakers in an anechoic room. The results of loudness and sharpness mapping revealed considerable sound source localization advantages, such as easier detection of the louder or sharper source, in comparison with traditional sound pressure mapping. Currently, practical measurements are being conducted in an engine room of the personal vehicle to validate the superiority of sound quality metrics mapping. Further studies are done on the individual sources with regard to their sound quality and to assess the overall sound quality of products, which generate noise with a certain directivity in space, using these array techniques. (Center contract)