Comparison between subjective evaluation and psychoacoustic parameters for car steering wheel rattle noise assessment

Rattle noise is one of the main concerns of automot ive manufacturers regarding final product quality. With the engine noise reduction obtained in electri c cars rattle noise becomes even more significant. Steering wheels are one of the car components prone to produce rattle noise. Current methods used in the industry for sound quality assessment are based mainly on subjective evaluation. This evaluation i s subject to variability, particularly for non-traine d technical staff, due both to differences occurrin g among evaluators, as well as variations for one sin gle evaluator when rating the same noise in different periods of time. Hence, an assessment ba sed on objective parameters would be desirable to provide more consistent results. In this work, nois e measurements have been carried out in the Centro Tecnológico de Automoción de Galicia (CTAG) semi-an echoic chamber using different steering wheels exposed to random vibration profiles approxi mating the real car conditions. The subjective evaluation carried out from a trained subject is co mpared with the psychoacoustic parameters (statistical loudness, statistical sharpness and ro ughness) computed from sound pressure measurements. The results show that only the statis tic l loudness provides a good correlation with the subjective tests but limitations in its application are found that suggest that further research must be done in order to obtain a robust objective evaluati on method for rattle noise.