Academy Users Report Vol.17

Department of Precision Mechanics, Faculty of Science and Engineering, Chuo University Acoustic Systems Laboratory

Quick to Pay Attention to Making Comfortable Sound According to Situations, Also Developing into Smart Sound Design / With UC-win/Road Used for Constructing Experimental Environment VR for Sound Quality Evaluation and Comfortable Sound Design

Department of Precision Mechanics, Faculty of Science and Engineering, Chuo University "Acoustic Systems Laboratory"
Location:Bunkyo-ku, Tokyo
Research and development contents: study on sound quality improvement and the comfortable sound design in a wide range of areas including automobile, household electrical appliances, and precision instruments

"Our laboratory does research on designing "sound" for various things. (As part of this) we change driving scenes of automobiles using VR (driving simulator (DS)) to see human reaction to the sound to be heard there."

20-odd years ago, the main way of thinking was to aim at noise reduction, as "sound" was regarded as "a bad and noisy thing", that is, noise. However, Professor Takeshi Toi, Department of Precision Mechanics, Faculty of Science and Engineering, Chuo University was based on the viewpoint that only lowering the volume of sound might also delete good sound, with the intrinsic fascination of sound such as operational feeling (flavor components) to get lost. With this idea, he developed his original study approach to "sound quality improvement" as a keyword, aiming at making best use of sound. Based on his own experience of joining an electric machinery company for a while after graduating university, he positively adopted joint research with outside companies, which was not so common at that time. In doing so, a plan has been made materialized to explore solutions to various social phenomena and problems related to sound.

In such a situation, he paid attention to the possibility of DS from early on in automobile-related studies. He looks back that he has been utilizing evaluation based on bio-information obtained by interlocking hearing sense with visual sense, and further with driving operation in working for various kinds of sound quality improvement and comfortable sound design.

In addition, through his activities of "Acoustic Systems Laboratory" which Prof. Toi teaches and Sound Quality Evaluation Technical Committee established in Society of Automotive Engineers of Japan, Inc., it has been requested to build up a simulator that reproduces actual driving situations more realistically in studying the relationship between acceleration feeling of an automobile and sound, or sound quality evaluation during driving based on biometrical information. To meet such needs, "UC-win/Road", a three-dimensional (3D) real-time VR produced by FORUM8 has been introduced as a tool to create diverse experimental environments.

With Research Base in City Center, Having Advantages Such as Industryacademia- government Collaboration

Chuo University was founded as Igirisu Horitsu Gakko (English Law School) in 1885. Under the founding spirit of "Fostering the ability to Apply Knowledge to Practice", the Univ. has been literally embodying practical education to make full use of intelligence for society.

The Univ. is currently organized by 6 faculties of Law, Economics, Commerce, Science and Engineering, Letters, and Policy studies; 7 Graduate Schools of Law, Economics, Commerce, Science and Engineering, Letters, Policy Studies, and Public Policy; and 2 Professional Graduate Schools of Law and Strategic Management. The Univ. has 690 fulltime teachers for about 26,000 students including undergraduate and graduate schools (as of May 2018). It has its educational and research bases in 4 campuses including Tama, Korakuen, Ichigaya, and Ichigaya Tamachi Campuses; and Surugadai Memorial Hall.

Among them, Faculty of Science and Engineering is organized by 10 Departments of Mathematics, Physics, Civil and Environmental Engineering, Precision Mechanics, Electrical, Electronic, and Communication Engineering, Applied Chemistry, Industrial and Systems Engineering, Information and System Engineering, Biological Sciences, and Integrated Science and Engineering for Sustainable Society. The Faculty is situated in Korakuen Campus along with Graduate School of Science and Engineering. Prof. Toi talks about the advantages of establishing campuses equipped with research facilities in the city center, taking for examples joint research with companies and planning and promoting industry-academiagovernment collaboration projects mentioned before.

There are more than 700 students of undergraduate and graduate schools in total in "Department of Precision Mechanics and Department of Precision Engineering", which aim to study advanced precision machinery. 14 laboratories including "Acoustic Systems Laboratory (Toi Laboratory)" are established.

Professor Takeshi Toi, Acoustic Systems (Toi)
Laboratory, Department of Precision Mechanics, Faculty of Science and Engineering, CHUO University
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From Website of Toi Lab.

Idea for Sound Quality Improvement and Concept of Comfortable Sound Design

"In old days, noises were so loud. Today, noises have become much smaller than the old days even in the offi ce environment."

It can be said that this is the result of working hard for noise reduction. On the contrary, however, "small noises" are now becoming obvious. Is it good to decrease the sound volume until no sound is heard? If so, no audible information can be obtained, even producing weird feeling. Then he wondered if the idea of sound quality improvement was needed. This was the motivation for him to start studying the concerned area, says Prof. Toi.

"In the beginning, we were designing comfortable sound for each product". Then it was converted to the idea like "let's make suitable sound depending on what is necessary in living environment or according to the time zones or purposes." Prof. Toi had come to pursue the stance to assume each of the sound source being a musical instrument and coordinate them so that people living there would not get tired or can feel them as comfortable acoustic environment (smart sound design).

In other words, the traditional approach was to manufacture something, and if the produced sound was bad, it would be regarded as uncomfortable sound and processed for noise reduction. On the contrary, he positioned production of sound to improve comfortability as "comfortable sound design". At the fi rst stage of manufacturing automobiles or household appliance, sound is determined to defi ne whether or not this contributes to the functionality of the product itself, for example, asking "is this comfortable to use if we make the sound like this?" To do so, however, it is necessary to evaluate the present sound. After that, the setting goal of sound should be decided. Then, a method has been formed to consider the whole thing throughout the process from evaluation to the feedback of design, for example, "How will the sound be changed by changing where in what way?", or "How should the design be changed to produce this sound?".

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Research cases on acoustics in the Lab

Utilizing Diverse ICT, Unique Research Developed in Broad Areas

When he established the lab 20 years and more ago, the term "comfortable sound" itself was hardly used. Therefore, he needed to explain from its defi nition even when he was making presentation in academic meetings. In recent years, however, the concept of "sound quality improvement" and "comfortable sound design" have penetrated so widely that they are ordinarily used.

On the other hand, "Acoustic Systems Laboratory" has about 10 undergraduate students and another 10 or so graduate students, and several researchers dedicated for joint research on the register. Regarding joint research with companies that the lab started to take in positively early, more than 10 themes are progressing at the same time in a year. Each theme is positioned as a project for 2 to 3 years. So far 200 and some 10 themes have been dealt in total.

One of the important facilities for these researches is an anechoic room. The Lab uses multiple rooms according to the purpose. They include two anechoic rooms as well as a semianechoic room capable of accommodating actual vehicles and large structures, which is the largest scale for a university in Tokyo. The Lab also utilizes wide-ranging ICT (information and communication technology). For example, they use software for oscillation analysis, acoustic analysis, and different kinds of numerical simulation; sensors to measure bio-information, acceleration, and sound pressure; measuring equipment to measure oscillation or acoustics, and various kinds of simulators.
Especially, combining and merging multiple software programs in their own way, the Lab is trying to draw evaluations from such points of view that have been overlooked so far, or feedback to the design based on these evaluations.

"In fact, there are not so many elements to deal with sound in the mechanical system."

Speaking of the world of sound, what are generally known includes architectural acoustics as well as electro-acoustics for deleting or making sound (active noise control and active sound control etc.). Based on precision mechanics, the Lab started with a study on noise that occurs from machines, refl ecting its specialty. In expanding its objects steadily, the Lab has been covering issues of sound in the areas of vehicles, offi ces, living spaces, and medical care and welfare.

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Explaining sound design for living environment

Introducing UC-win/Road for Studies on Vehicles, Future Development and Challenges of Studies

In recent years, Acoustic Systems Laboratory had tendency to do various kinds of research on sound regarding automobiles using DS through joint research etc. Prof. Toi reveals that his fi rst frank impression about UC-win/Road was "being capable of creating motion pictures nicely, with comparatively affordable price compared with other software programs we have".

Several years ago, he came up with a research idea as follows: "Is it alright that the driver's seat, the passenger seat, and back seats have the same sound environment, or is it necessary to have different sound environments for each seat?" In trying to build up experimental environment for evaluating sound for each of "sound only", "sound and vision", and "sound, vision, and driving operation" in the laboratory, it is rather hard to handle without using a tool like UC-win/Road in the part related to vision and driving operation. In particular, when trying to add some driving conditions, the display and sound were required to change linked with the acceleration and deceleration of the vehicle. This made them consider introduction of UCwin/ Road to meet such needs.

Almost at the same time, as mentioned at the beginning, when he heard from the working group studying acoustic evaluation in vehicle driving using bio-information that they want to represent actual driving conditions more realistically, in Sound quality evaluation technical committee (Society of Automotive Engineers of Japan, Inc.), with which he had been involved from its establishment, he introduced UC-win/ Road to them, which was adopted as a result.

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Experimental environment for evaluating appropriate alarm sound created with UC-win/Road
(simulation executed by switching day and night, clear and rainy sky)

For example, for the scene where a person is running out of a side street, UC-win/Road is actually used to create environment to see at what timing the alarm sound should be made in advance for the driver to perceive the scene more safely. He says that he realized its convenience in that it is easy to switch day and night or clear and rainy weather. What's more, it was made easier to represent the travelling environment, which was rather diffi cult before. Additionally, since the created sham driving environment changes according to acceleration (rapid and slow) or based on the driving operation etc. for various kinds of events set on the route, it exerts excellent oneness. Furthermore, he evaluates that it can be a very strong tool since all logs are kept. Particularly, in the sense of seeing the change in sound environment accompanied by operational system, UC-win/Road is easy to use, and useful for constructing comfortable and functional smart sound design, says Prof. Toi.

On the other hand, he expects from an acoustic specialist's point of view that it makes it possible to raise the degree of freedom for sound such as sound quality control. At the present, one of the big challenges is to monitor human information. For example, if emotion can be monitored, appropriate sound environment and oscillation environment are to be created based on this. He says that what they should do from now in relation with automobiles is to build up environments that refl ect fi ve senses based on such monitoring.

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Lab members around DS applying the experimental environment of UC-win/Road in the anechoic room
(Written by Takashi Ikeno)
(Up&Coming '18 Summer issue)