Rika Hosaka

Effect of Tonal Harmonic Feature in Product Noise on Emotional Quality

The product sound is an important factor that affects the product emotional quality. In the design of product sound quality, a designer needs to find the design factors that affect the emotional quality and determine the characteristics of their effects. The authors previously proposed a method for extraction of potential emotional factors by analyzing human sensitivity towards unexplored design and applied the method for designing product sound quality. From the result using vacuum cleaners as a case study, the authors found that the existence of prominent peak tones in sound has the potential to improve sound quality. However, prominent peak tones are usually regarded as a factor of annoyance. In this paper, we propose an indicator for adjusting the frequency and level of peak tones to improve a product sound quality. We have assumed that the harmonic features of peak tones in noise can be used as the indicator. We created vacuum cleaner sounds having three peak tones whose harmonic features such as tonal consonance and modality are different. To evaluate the effectiveness of the harmonic features, we conducted a pairwise comparison-based sensory evaluation with two groups of participants, one consisting of those who play some musical instrument and the other of those who do not. From the experiment, we found that the peak tone harmonic features can be perceived by both groups of participants and significantly decrease their annoyance at vacuum cleaner sounds.

A Method for Extraction of Potential Emotional Quality by Analysing Emotional Response Towards Unexplored Design: Application to Product Sound Quality

An emotional quality is a product quality that is evaluated by the customer’s subjective impressions, feelings and emotions. In the design of emotional qualities, one of the most important and difficult issues is setting quantitative evaluation criteria to evaluate such qualities. The customer’s sensitivity towards such qualities is diverse and latent. In our previous study, we proposed a quantification method of emotional qualities with attention paid to its diversity [1]. 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 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 propose a method to cover such untouched design space using composite samples in order to extract a potential factor of emotional quality for the future design. To create such a composite sample, we set efficient design features that take into consideration the completeness of design space and the diversity of a target emotional quality. In the method, we conduct two sets of sensory tests. One is using only existing design samples and another is using composite samples. We compare the results of the two tests in order to examine the repeatability of emotional scores among different sets of subjects and changes introduced by adding created samples. We apply the proposed method to extract potential emotional factors of product sound quantify. Using results of the sensory test with the created sound samples, we found two emotional evaluation factors. The first factor negatively related to loudness. The second factor related to lower sharpness and the existence of a perceivable peak tone around 500Hz. Most product makers are aware of the need to reduce loudness, i.e., the first factor. We found the second factor as a new evaluation criterion.Copyright

Quantification Method of Diverse

This paper proposes a quantification method of a product’s emotional quality, which we call kansei quality, with attention paid to its diversity to support the affective design. The customer’s sensitivity towards such a quality differs from person to person due to perception gaps and ambiguity. The proposed method helps the designer to grasp such diverse sensitivities of customers. In contrast to the conventional approach that aims to generalize human sensitivity using average results of sensory tests, the proposed method divides an emotional quality based on differences among the customers’ sensitivity. We apply the proposed method for designing a machine sound in which the designer deals with the sound quality as a kansei quality. We carry out an impression evaluation experiment on human subjects using existing product sounds. To demonstrate the effectiveness of the method, we compare the proposed method with the conventional approach using experimental results. The comparison results show the advantages of the method, such as the avoidance of meaningless average data caused by canceling out multiple different sensitivities. Based on the proposed method, we developed a prototype system that enables the designer to evaluate the kansei qualities of a created sound without conducting a sensory test.Copyright