The Influence of Sharpness on People's Responses to Wind Noise Inside Automobiles

As part of the ongoing effort to reduce noise inside automobiles, laboratory experiments are being conducted to generate predictors of human response to noise from airflow around the automobile. It has been demonstrated through a previous experiment that a model of acceptability based on Loudness and Sharpness is significantly more highly correlated to peoples' responses to steady-state wind noise than a model based on Loudness alone. The test described in this paper was conducted to validate this model. Subjects in the test sat in a sound booth and listened to sounds presented over earphones. Sounds were recorded with binaural heads in various cars placed in a wind tunnel. Some of the sounds were modified by filtering to vary Sharpness while controlling Loudness; this allowed for a more in-depth examination of the effects of Sharpness on people's responses. The test was split into two parts, each consisting of a Likert scale test in which subjects rated sounds on an acceptability scale. The degree of agreement between the results of this test and the results of the previous test is examined.