In recent years, various sounds have become the objects of design. Acoustic design of musical instruments and concert halls has long been conducted to satisfy the human aesthetic desire to listen and play good sound. These are sounds and places intended to be appreciated, but other sounds have also become the objects of design; for example, the sounds of the environment in which we live, the sounds of auditory signs to convey information, and the sounds of machines such as motors, engines, and doors opening and closing, and so on. The purpose of design varies, for example, to ensure that the sound plays its proper role, or that people are comfortable in their environment. This awareness of sound design is related to the growing interest in quality of life (QOL) and usability of products and services in a mature society after high economic growth. The application of design to sound, which has been considered noise, was initiated by the limitations of conventional quantitative evaluation and countermeasures based on such evaluation.

For example, the concept of soundscape (see below), which is considered as a theoretical framework for the design of sonic environment, was proposed during the 1960s and 1970s. It started when proponent R. Murray Schafer questioned the conventional mechanistic approach to noise problems and people’s attitude toward the sonic environment, and after various projects, it was systematized in his main book, The Soundscape: Our Sonic Environment and the Tuning of the World. Also, with the recent development of electronic technology, the use of auditory signs (including warning sounds) for the purpose of conveying information have spread rapidly, resulting in an overflow of them and confusion, and it has become necessary to design them appropriately. The sensory evaluation and design of machinery noise began with the sound quality study of automobile engine noise by Andrews et al. (1979) against the background of the limitations of noise reduction and cost issues. As mentioned above, sound design has been developed based on the awareness of issues in each field. Sound design can include organizing the relationship between humans and sound as well as creating the optimal sound based on consideration of how sound should be in the society and environment in which people live, and creating an environment in which the sound can function properly. In the following, we will discuss the concept and development of sound design by focusing on the design of sonic environments based on the concept of soundscape and the design of auditory signs.

Soundscape is a term coined to mean “landscape of sound,” and means an acoustic field composed of all the events heard by individuals and society. The sound is perceived in relation to the meaning, context, people’s life, and society. With this perspective, we can create a better sonic environment by removing or preserving sounds and arranging them appropriately. This is the design of sonic environment based on the concept of soundscape. A concrete example is Rentaro Taki Memorial Museum (Takeda City, Oita Prefecture, opened to the public in 1992), which tried to recreate the soundscape that a famous musician would have listened when he was a child. Furthermore, the Ministry of the Environment of Japan conducted a project to select sound sights and “soundscapes to preserve” throughout Japan. These activities are aimed at promoting awareness of sound and the relationship with the environment, which will lead to its conservation.

The term “design of sonic environment” is not synonymous with “soundscape design.” Soundscape design has a broader meaning. It is believed that the actual creation of the sonic environment should be done by ordinary people, and thus design reflects the individual’s awareness and sensitivity toward sounds and the sonic environment. Therefore, in addition to approaches to sound itself, such as adding or removing sound and preserving the sonic environment, education, which nurtures people’s sensibilities, is also considered an act of design (Keiko Torigoe, 1997). Accordingly, soundscape design includes the selection of “soundscapes to be preserved” and the training in the act of listening (sound education) as well.

The warning sound used in emergency situations should be designed carefully. The auditory sign that alert people to dangerous situations such as fires and earthquakes. Another example of auditory sign except the warning information is the guidance for the visually impaired people. Those should not be disturbed by environmental sounds, and should be audible to people of all ages and easily understood by listeners of different cultures and nationalities. To design such auditory signs, it is necessary to understand the listners’ perception and cognition. For example, it is known that sensitivity to high-frequency sounds decreases with age. This means that auditory signs used by many people should be designed to function independently of such perceptual characteristics. According to the some studies on the listeners’ perception and meaning of auditory signs, listeners generally perceive sounds with the higher fundamental frequency and the faster interruption rate as being more urgent. Therefore, these characteristics should also be taken into account. The information of the auditory sign is not only alarm or urgency. A product’s auditory sign can be added to provide a variety of information, such as the acceptance of operation, the termination of processing, and the operating status. Since it is assumed that various auditory signs will be sounded simultaneously from multiple products and even from the same product, auditory signs should be designed according to their functional imageries in order to ensure that the meaning of each sign is correctly understood.

The design guidelines of auditory signs including the above have been organized as international standards. For example, the international standard ISO 8201:2017 standardizes acoustic characteristics, operation methods, and testing methods for emergency evacuation signals, and the “Guidelines for older persons and persons with disabilities – Auditory signals for consumer products” shows the recommended acoustic characteristics of auditory signs for home appliances according to the purpose of the sign. In Japan, JIS S 0013:2011 provides design guidelines for auditory signs added to products for the elderly and visually impaired.

Sound is used to solve problems manifested by changes in people’s awareness and society, and the process of creating the optimal sound for a purpose or situation is the sound design. The “optimal” depends on the purpose and situation. In some cases, advanced design is required, not only in terms of functionality, but also in terms of user sensibility. Although user sensibility differs with culture, nationality, and individual, we believe that there are indeed sounds that appeal to the sensibilities of many people. We are currently analyzing perceptual structures related to sound evaluation and trying to elucidate the design methodology of sound that add value to objects.

(TAKADA Masayuki, YAMAUCHI Katsuya)

Related Classes

Acoustic Design Course Technical Listening Training I

Acoustic Design Course Rating and Control of Noise

Acoustic Design Course Acoustic Environment Assessment

References

• ISO 8201:2017 (2017), Alarm systems — Audible emergency evacuation signal — Requirements.
• Murray Schafer, R.(1977), The Tuning of the World, Random House Inc. （Ｒ.マリー・シェーファー（2006）『世界の調律』鳥越けい子他訳、平凡社）
• Andrews S.A., D. Anderton, J.M. Baker (1979) “The Analysis and Mechanism of Engine Crank Rumble,” Proc. of Institution of Mechanical Engineers, 99-109.
• Takada M., H. Mori, S. Sakamoto, S. Iwamiya (2019), “Structural analysis of the value evaluation of vehicle door-closing sounds,” Applied Acoustics 156, 306-318.
• JIS S 0013:2011 (2011)「高齢者・障害者配慮設計指針－消費生活製品の報知音」
• 環境省、残したい日本の音風景100選
• 財団法人家電製品協会（2001）『家電製品における操作性向上のための報知音に関するガイドライン』
• 鳥越けい子（1997）『サウンドスケープ その思想と実践』 鹿島出版会