Development of a Sonic Branding Process for Designing Automobile Engine Sound Based on Affective Engineering Approach

Abstract

Sonic branding is an auditory method by which brand identity can be<br/> presented. There are previous studies to group car sounds into three<br/> categories, namely electronic sound, engine sound, and operation sound, as<br/> an auditory user interface (AUI) and studies are conducted to apply sonic<br/> branding to all AUIs in cars. In this context, car makers have put effort to<br/> make their brand images appealing to customers using engine sound<br/> achieved by hardware improvement, including intake and exhaust systems,<br/> for decades.<br/> <br/> Car makers are trying to represent their brand identities using active<br/> sound design (ASD) systems, which are software solutions for engine sound<br/> design that can be applied to current infotainment systems. Software<br/> developing companies in Germany, France, and the UK have launched their<br/> own ASD solutions, and the maturity of the software reached to a certain<br/> level at which the solutions can be applied to mass production of cars.<br/> Considering that the differences in hardware performances depending on the<br/> brands are currently less than those before, the interest on ASD in the<br/> automotive industry globally as a key method for improving affective<br/> quality and presenting brand identity using engine sound, which is an<br/> important AUI in automobiles, is increasing. However, most of previous<br/> studies on ASD are for ASD algorithm development and there are few<br/> previous studies on the ASD development process, which can be applied to a<br/> real engine sound design. Moreover, it is known that car manufacturers have<br/> difficulties in finding methods as to which brand identity can be presented<br/> using the ASD system in their cars.<br/> <br/> In this study, a sonic branding process for ASD is proposed, by which<br/> brand identity and image is evaluated based on the acoustic parameters of<br/> engine sounds, and to which a sonic branding method can be applied. The<br/> overall development process has been built based on previous studies on the<br/> AUI development process to keep its reliability. Subjective ratings,<br/> interviews, and questionnaires, which are subjective measurement methods<br/> for affective engineering, were used to propose methods for evaluating and<br/> designing of engine sounds. A regression model for engine sound, which<br/> shows the causal relationship between acoustic parameters and affective<br/> adjectives, was derived for efficiency in evaluation and design.<br/> <br/> For this purpose, a sonic branding process, by which levels of affective<br/> adjectives of original engine sounds were evaluated on the positioning map<br/> and were adjusted to new target positions to improve brand identity using<br/> regression equations for acoustic parameters and affective adjectives, was<br/> proposed. The positioning map is a two-dimensional grid for engine sound<br/> evaluation, which has been used in previous studies. Second, a jury test was<br/> conducted to propose regression equations, which are required for the sonic<br/> branding process, and the result of the jury test was analyzed using statistical<br/> methods to find the causal relationship between affective adjectives, which<br/> present brand identity and car class, and acoustic parameters of engine<br/> sounds. Third, new affective synthesis methods, which can be applied to<br/> engine sound design using ASD, were introduced. Synthesis methods,<br/> including musical harmonic theory and formant filter, which are being tried<br/> by car manufacturers currently, were described, and new methods including<br/> pipe organ mixture, break back, and beat effect were proposed. Fourth, new<br/> engine sounds were developed on the ASD system equipped in target cars<br/> following the sonic branding process to test the validity of the process. The<br/> engine sound design was conducted in cooperation with a sound design<br/> expert, who has insights for sound design. Six engine sounds were designed<br/> in total and the positions of five engine sounds were found in the range of<br/> target positions. Even if the position of one engine sound design was out of<br/> range of the target position, the direction of movement was still within the<br/> intended trendline.<br/> <br/> The result of this study can be used to develop sonic branding for engine<br/> sound. Development time can be decreased and the possibility of success<br/> will be increased using the sonic branding process proposed in this study. In<br/> addition, the regression model for engine sound developed in this study will<br/> be helpful for estimating the character of new engine sounds for ASD<br/> systems in advance. Estimating new engine sound characters will contribute<br/> to proper engine sound designs to attain an efficient brand identity strategy<br/> using engine sound.<br/> <br/> However, the jury test was conducted for participants who have Korean<br/> nationality and luxury and sporty car owners were excluded from the test. To<br/> adapt the result of this study globally, additional study considering the<br/> nationality and owned car type is necessary. In addition, sonic branding for<br/> electric/hybrid vehicles based on the result of this study could be an<br/> interesting topic for a future study.