Consumers purchase a product on the basis of satisfying their unmet needs. However, several factors related to acoustics may impact the individual's perceptions of a product. For this reason, vehicle manufacturers include sound quality evaluations to find out what exactly motives or influences a consumer behavior when purchasing a new vehicle as sound quality is considered by consumers as an important index that reflects quality of a vehicle. Many studies related to sound quality evaluation of vehicles have been investigated by researchers. For those which are based on sound samples transmitted by using headphones, one of the first question that arises is either the sound samples should be volume-adjusted to share similar global loudness or not. Some studies suggest that the sound samples should be equalized in global loudness to help test-subjects to focus on finer details rather than the obvious overall perceived loudness level while other studies mention that such equalization is not required because such volume adjustment could alternates the nature of the product and the overall consumer perception of the product. However, very few studies have actually made a scientific comparison of the two approaches. In order to clarify this everlasting question, a three parts sound quality evaluation campaign has been designed. The objectives were: (1) to extract vocabulary related to the listened vehicle by using a focus group, (2) to evaluate the sensory profiles with sound samples being loudness-equalized by using a first listening test and (3) to compare these sensory profiles with the ones obtained with a second listening test not loudness-equalized. Results reported and discussed in the present study shown that both sound quality evaluation methods have advantages and provide relevant and coherent information.
