Abstract
In the design of emotional qualities, one of the most important and difficult issues is setting quantitative evaluation criteria to evaluate such qualities. Without such evaluation criteria, the designer has to rely on his/her sensitivity, which may be different from the customer's, making it difficult to set a clear design goal. The customer's sensitivity towards such qualities is subjective, tacit and diverse. In our previous study, we proposed a quantification method of emotional qualities with attention paid to its diversity (1). We applied the method to quantify the diverse emotional qualities of a product sound. The method analyzes the diversity of emotional qualities and formulates their evaluation criteria based on the results of sensory tests. The authors formalized several emotional qualities expressed by adjectives using the proposed method with sound samples recorded from existing products. However, the variety of existing products was limited. The obtained evaluation criteria may not cover a design space where future designs would appear. In this paper, we aim to cover such untouched design space using composite sounds and extract a potential factor for the future design of sound quality. To create such composite sounds, we set efficient design parameters that take into consideration the completeness of design space and the diversity of a target emotional quality that we quantify using the results of sensory tests in the previous work. For the present work, we conduct a new set of sensory tests and compare the results with those from our previous work, in order to discuss the repeatability of emotional scores among different sets of subjects and changes introduced by adding created sounds. We extracted a new emotional scale of target emotional quality "expensiveness of machine sound" that was not found in 1^<st> sensory test based only on the existing product sound. The emotional scale contains two different viewpoints of "reliable sound". One is associated with silent and composed sound and another is powerful and obstructed sound. Using a factor analysis considering the diversity of human sensitivities, we found those two viewpoints of "reliable sound" in 1^<st> and 2^<nd> factors respectively.
