Quietness, Comfortable Sound and Excellent Acoustics NAGATA ACOUSTICS

News 12-01 (No.289)

Issued : January 25, 2012

[ Japanese Version ]

Kadare Cultural Center Opens in Yurihonjo City, Akita Pref.

By Ayako Hakozaki

Kadare Cultural Center exterior
Kadare Cultural Center exterior

In the southern part of Akita Prefecture, at the foot of Mt. Chokai, the city of Yurihonjo spreads out on land that faces the Japan Sea. Here, the local population has long enjoyed the natural bounties of good land and fresh mountain springs. The city developed centuries ago around Honjo Castle. (The castle was destroyed in 1868.) The area produces delicious rice and has a large number of sake breweries that rely on the local availability of both the rice and the abundant and tasty water from Mt. Chokai.

At the end of 2011, Yurihonjo City celebrated the opening of Kadare Cultural Center. Public train transportation provides easy access to the center, which is a convenient five-minute walk from JR Ugohonjo Station.

The city ran a contest requesting submissions for the center's name and received suggestions from people throughout Japan. The chosen name of "Kadare" combines the Akita dialect's word "kadare", which means to include in one's group, with the Japanese verb "katari-au", which means to talk or chat with another person or a group of people.

Chiaki Arai Urban & Architecture Design served as the project architect and construction manager. Toda Construction built the center.

Floor plan
Floor plan

Wai-wai Street
Wai-wai Street

<< Overview of the Center's Facilities >>

Kadare Cultural Center has a main hall zone, a library zone and a community center zone, plus a natural sciences study zone that has a planetarium and astronomical observatory. In addition, there is an indoor walking mall named Wai-wai Street, restaurants and a shop that handles locally made products. All of these facilities existed in various buildings before the construction of the new cultural center, but the buildings had deteriorated with age and the city decided to combine all of their functionalities under one roof.

Wai-wai Street traverses Kadare Cultural Center from north to south, creating a thoroughfare with shops that connect visitors to the hall's entrance, the library, the gallery and other center facilities. The thoroughfare's architectural design and shops give it a feeling of vitality and activity that makes it easy to forget that you are indoors and, instead, creates the enjoyable illusion of strolling along a pleasant and interesting walking street.

The center's interior walls are exposed concrete. The interior design placed embedded lighting in the recesses left by the snap ties (a part used during the process of placing the concrete in forms). The ceiling is finished with several varieties of perforated metal panels installed in a random pattern. Occasional pieces of wood furniture placed throughout the center add a warm ambience as do some star-shaped light fixtures.

Planetarium in the Municipal Science Room 2
Planetarium in the Municipal Science Room 2

Main Hall (with seating)
Main Hall (with seating)

Main Hall (with seating stored away)
Main Hall (with seating stored away)

Super Box
"Super Box"

<< The Main Hall's Configurable Seating >>

The main hall is a multipurpose hall with a proscenium stage and a maximum seating occupancy of 1,100 persons. The architect planned the hall included emphasized closeness between the stage and the audience as well as good sight lines to the stage. The implemented design therefore minimizes the physical distance from the stage to the audience seats and achieves a feeling of intimacy between performers and audience.

To enable flexible use of the main hall's space, the hall's orchestra level floor has storable stands (bleachers) and seating wagons instead of fixed seating. Storable seating stands have a reputation for being uncomfortable, even when equipped with individual seats and backrests. They also often wobble when people walk along the rows. For this project, the client insisted that the storable seating not wobble, and that the comfort level of the seats come close to matching that of fixed seating. Several rounds of designs and improvements achieved the desired result, and this hall's seating stands are built so that they do not wobble and with very comfortable seats.

The seating stands can be stored by collapsing them into a stack under their last (highest) row and then lowering them into storage space below the flat floor of the main hall. Seating wagons for the front rows of the hall can also be stored. When all of the seats are stored, the first floor can be raised to the height of the stage, creating a roomy, flat-floor venue for exhibitions and similar uses.

<< Transforming the Main Hall into the Super Box >>

For events requiring larger floor space than the flat-floor configured main hall can provide, the hall and other rooms can be combined into the extra-large "super box"space. The center's layout has the main hall, a public activity room and the gallery in an aligned row, with each room only separated from the adjacent ones by removable dividing walls. When the dividing walls are removed, the combined rooms form a very large, flat floor, rectangular space.

The super box space will enable Kadare Cultural Center to attract bookings for events that need a very large indoor space. Yurihonjo has an annual summer festival organized by a Shinto shrine and one already proposed idea would bring indoors to the new super box the part of the festival known as Daimyo Gyoretsu, which is a long procession of people in historical costumes from Japan's feudal period.

<< Acoustical Consulting for the Kadare Cultural Center Project >>

In a multi-use facility such as Kadare Cultural Center, sound isolation between spaces with different functions is a key component and objective of our acoustical design. For the hall zone, we specified the use of acoustically effective expansion joints to prevent the transfer of solid-borne sound. Additionally, because the walls between the main hall and the public activity room must be able to be removed to form the super box room, we specified double layers of dividers that have sound-isolating characteristics. We also adopted anti-vibration and sound isolating structural designs for the public activity room, the studio and the practice rooms to obtain a high level of sound isolation for each of these spaces. Our design enables simultaneous use of all of these rooms.

For the main hall, our acoustical room design included an on-stage reflection panel system. We aimed to achieve a hall configuration that allows the reflection panel system to create a feeling of continuity between the stage and the audience seating areas. Our design also minimized overhang of the first floor seating by the balconies. In the design of the balcony blocks, we focused on creating sections and wall portions that will serve as sound reflecting surfaces.

Special Opening Concert with Sendai Philharmonic and chorus of local singers
Special Opening Concert with
Sendai Philharmonic and chorus of local singers

The main hall's white ceiling, designed with multi-faceted geometric shapes, extends from above the stage to the rear of the audience seating. To cause the ceiling to produce a large amount of sound reflections, we carefully specified the angles of the ceiling's surfaces. We also prevented overly harsh reflections from the concrete side walls by adding random ribbing and small indentations in the concrete walls. Behind the random ribbing on the upper portions of the side walls we installed sound-absorbing curtains that can be drawn open or closed to adjust the reverberation time in the audience seating area. When the hall is configured with the sound reflection panel system, the reverberation time measures 1.7 seconds (at 500 Hz, in a fully occupied hall).

<< Opening Events >>

On December 23, 2011, Kadare Cultural Center held its Special Opening Concert featuring the Sendai Philharmonic Orchestra and a chorus of local singers in a performance of Beethoven's Ninth Symphony. The chorus of some 170 people included a broad spectrum of the community, from elementary school children to senior citizens, most of whom had never before performed this Beethoven work. To prepare for the performance, they practiced and rehearsed for six months.

The chorus gave a performance full of passion and enthusiasm. The hall's acoustics had clarity and fullness. The sold-out concert filled every seat in the hall and long applause rang through the hall at the concert's conclusion.

Acoustical Design Legacies and Lessons of Older and Bygone Halls - Part 1

By Dr. Minoru Nagata, Founder of Nagata Acoustics

My professional work in the field of acoustical design and engineering began in October, 1949 when the Japan Broadcasting Corporation (today's NHK) hired me as an employee of its Technical Research Institute of Japan Broadcasting Corporation. At the time, the institute had several departments and dedicated all its work to radio broadcasting research.

<< Radio Broadcasting Studios the Acoustical Design Focus of the 1930s and 1940s >>

In 1931, in a corner of Tamura-cho, Shimbashi, part of Tokyo, NHK built the JOAK (NHK's radio call name) Tokyo Broadcasting Bldg. I once saw a document with calculations of the sound reverberation times of the broadcast studios in that building. In those days and during World War II, NHK also constructed broadcasting studios in other Asian countries and kept records of the accumulated empirical data obtained from the construction of the studios.

The ravages of war followed by the shock of Japan's defeat took a huge toll. Four years after the war's end, in 1949, Japan's reconstruction and revival was just starting to gain momentum. When I joined Technical Research Institute of Japan Broadcasting Corporation and was assigned to the group working on acoustics, NHK had just accelerated the rebuilding of Japan's nationwide radio network and was pursuing this goal at a feverish pace.

<< The Advent of the Age of Television >>

When I started my employment at Technical Research Institute of Japan Broadcasting Corporation, apparently just about everyone else was involved in, or trying to become involved with NHK's ambitions for a next generation of broadcast media, but I knew nothing about this and certainly had no idea that a new media was about to be born and that it would fundamentally change NHK's research focus and organization. The new broadcast media was, of course, television.

In June, 1951, Technical Research Institute of Japan Broadcasting Corporation implemented a total structural reorganization. It created four research departments, one dedicated to television, one to electron tube research, one to wireless technologies, and one for acoustical research, plus a fifth division in charge of developing prototypes.

Within the Acoustics Research Department, NHK established six research sections for sound equipments, recording, audio frequency circuits, architectural acoustics, sound effects and acoustical materials. This was the first time that a Japanese research institute organized itself to comprehensively cover every aspect of acoustics that pertains to broadcasting.

Television broadcasting in Japan began two years later in February, 1953. Television's arrival added visual imagery to a broadcasting world where audio reigned and the birth of this new media presaged revolutionary changes. The black and white images received by early televisions were of extremely poor quality, but over the course of the next 50 years technology advanced rapidly and the quality of images on television screens improved by leaps and bounds.

<< Audio Becomes a Digital Medium >>

Meanwhile, in the world of audio, phonograph records changed from SP to LP, followed by the use of magnetic tapes, CDs, memory chips and cards, each replacing a previous technology until today's virtual storing of audio in "clouds". Probably, digital signal processing can be identified as the key impetus that enabled these developments. Recorded audio signals could be stored on a chip smaller than the head of a household match. Digitization made small, lightweight devices possible. However, the sound entrance points and exits to this digital world, that is, microphones and loudspeakers, still rely on some vestiges of their technological origins even in their most innovative iterations.

The ubiquitous adoption of digital technologies also precipitated some losses. Compared with the years known as the age of audio, when interest in LP recordings was at its peak, the then vibrant culture centered on musical recordings has been relegated to the sidelines in the digital age. Concern for the sound quality of the human voice and speech has diminished to the point that the human voice serves merely as an information communication tool. Smart phones may represent an aggregation of today's most advanced technologies, but they often supply such a low-standard of audio performance that it can be difficult to identify the owner of a voice at the other end of a call.

<< Digital Television Overshadows Audio's Value >>

In Japan, digital terrestrial broadcasting technology significantly improved the quality of images viewers see on television screens. The move towards high definition television technologies in television devices and by broadcasters will also result in higher quality television images.

Surely, the information that end-users obtain from visual images far exceeds the information they gain from an audio recording and visual images strongly affect viewers. With audio now generally thought of as solely a way to provide auditory information to end-users who are primarily media viewers, NHK's interest in broadcasting sound now focuses on using multichannel technology to reproduce virtual space. This research focus points NHK in a direction away from valuing the aesthetic beauty of sound and its profound complexities.

<< The Beauty and Pleasure of Fine Audio Still Found in Concert Halls >>

Despite the trends I described in the above paragraphs, places that require and highly value the beauty and pleasure of environments with fine acoustics can still be found in the world of concert halls. The acoustics of concert halls make this possible. The acoustical properties of a room are related to the structure of the room's sound fields. When our scientific understanding of the nature of sound fields became elucidated in the latter half of the 1970s, the results of this research began to be applied to the design of concert hall room acoustics.

The discipline of architectural acoustics comprises, in addition to the design of room acoustics, the fields of sound isolation and sound system design. In the years when I was a member of NHK Labs' Acoustical Research Section, our objective was to achieve pleasing sound environments and this goal permeated every aspect of our design methodology, from the architectural planning phase through a hall's physical construction. We turned our research into reality in 1961, with the completion and opening of Tokyo Bunka Kaikan in the Ueno, Tokyo. In Japan, this hall's opening ushered in a boom era of building for concert halls and other cultural facilities that was propelled forward, in part, by Japan's very rapid economic growth (eventually spiraling into a bubble economy). However, in the midst of this boom, in June, 1970, NHK closed down the Acoustical Research Section, ending its 20-year history just a few short years before some of the discipline's most valuable advances.

Within the discipline of architectural acoustics, I've focused throughout my professional life solely on my goal of achieving the ideal sound environment requires the three aspects of "Quietness, Comfortable Sound, and Excellent Acoustics". This ideal relates to human sensory perceptions and is therefore an ideal tied to the human condition and an eternally relevant research pursuit.

Three years ago, a number of the colleagues I worked with at NHK Labs' Acoustical Research Section and I joined together to compile and publish the research papers and technical documentation produced during the section's 20 years of existence. Now I want to draw on my half century of work with sound and acoustics to shed light on some worthy bygone halls and overshadowed technical insights and accomplishments.

Within the field of room acoustical design, the room design methodologies for concert halls have advanced to a place where I think they will remain for some time. However, when I contemplate the path forward for classical music and the future of live performances on hall stages, I return to acknowledging that the relationship between sound and architecture is anything but simple. As today's technology pioneers to forge ahead in new areas of research, I think it will aid them to glean some things from the knowledge and sweat of those of us who precede them. With this idea in mind, I begin this new series of essays. Next time, I will write about Yamaha Hall, a hall that opened in Tokyo's Ginza district immediately after the end of World War II.

JATET Forum 2011: Reporting on the Great Tohoku Earthquake's Damage to Theatres and Halls

By Makoto Ino

Attendees filled the hall to capacity at JATET Forum 2011
Attendees filled the hall to capacity at
JATET Forum 2011

On Thursday, December 15, 2011, 280 attendees participated in JATET Forum 2011 at Owl Spot Theater in the Ikebukuro, Toshima City section of Tokyo. JATET (Theatre and Entertainment Technology Association, Japan), Owl Spot Theater and the Toshima City government sponsored the meeting with co-sponsorship by the Association of Public Theaters and Halls in Japan.

JATET devoted the 2011 gathering to the completed report of investigations into the theatres and halls that suffered damage in last year's earthquake, including the recording of eyewitness accounts from these facilities' managers. The main purpose of the report is to provide information and analyses that can be used to determine ways to better protect against future disasters and ensure public safety.

Prof. Shozo Motosugi of the College of Science and Technology, Nihon University served as the investigation's Executive Chairman. Prof. Hideaki Katsumata of the Department of Architecture, Faculty of Engineering, Tokyo City Unversity acted as Editor-in-chief of the 300-page report. Just weeks before the earthquake I had assumed the position of chairperson of the JATET Acoustics Division, replacing the outgoing Mr. Yasuhiko Yahata of Space Creators Alliance Inc. In my new capacity, I participated in the research for the report by collecting data on damage sustained by each JATET member company and the stage sound systems with which they are associated. At JATET Forum 2011, I reported on these findings during Part 2 of the meeting.

The day's proceedings were divided into three parts. The first part reviewed the report's findings, the second part focused on the reported damage to aspects of halls that JATET members design and install. During the third part of the forum panelists discussed reconstruction and other forward-looking efforts.

<< The Report's Overall Findings >>

During the presentation of the report's findings, we heard about the investigation's results of the extent of architectural damage, the measures taken by various hall managements at the time of the earthquake and during its immediate aftermath, and the state of reconstruction after the disaster. One memorable account came from the management of Sendai Sunplaza Hall. At the time of the earthquake, the hall was being used for graduation ceremonies with nearly 2,000 attendees. The hall's manager evacuated everyone from the building. Shortly after the evacuation, the hall's ceiling fell. The manager's quick decision and appropriate action averted both loss of life and many injuries.

Because Sendai Sunplaza Hall wasted no time in pursuing reconstruction, it was able to reopen in July, 2011. By comparision, of 44 theatre and hall buildings in Miyagi Prefecture, the reopening of 15% of them still remains undeterined.

In the area affected by the earthquake, the survey researched 855 public halls. With the exception of a small number of halls in the Kanto region and halls in the path of the tsunami, the report was able to verify that no injuries occurred in any of these halls.

Damaged halls and estimated seismic intensity

<< Earthquake Damage to Stage Machinery, Lighting and Sound Systems >>

In the second part of the program, speakers presented the results of surveys done by the Stage Machinery, Lighting and Acoustics groups. For each group's equipment, the number of facilities damaged by the earthquake was compared to the number of facilities in the survey. For stage machinery, of 758 facilities surveyed, 227 facilities had damage. For lighting, of 940 facilities surveyed, 77 had damage. For stage sound systems, of 552 facilities surveyed, 67 had damage from the earthquake.

As might be expected, counterweights, risers and other heavy stage machinery devices sustained comparatively more damage than lighting and sound system equipment. Within the category of sound system equipment, loudspeakers were the most reported damaged item, three-point microphones and related equipment were the second most reported item and portable devices were the third most reported damaged item.

In most halls, the loudspeakers are not attached directly to the ceiling. Instead, they are hung from brackets that are not integral to the speaker enclosures but independent parts and most of the speakers are suspended using steel wire. Speaker installation always includes a wire intended to prevent the speaker from swaying, but this wire is thin and the survey documented that in many cases of damage, this wire broke or became separated from the speaker. Apparently, there were no incidents of any speakers falling to the ground.

<< Panel Discussion about Reconstruction and Future Initiatives >>

The third part of the meeting featured a panel discussion about general disaster recovery efforts, reconstruction and revival of cultural operations in facilities in the earthquake zone. Prof. Motosugi led the discussion. Government representatives responsible for cultural facilities and managers from halls and theatres from the Tohoku region participated.

In addition to the findings presented at the forum, the published report contains other information provided by many people involved in theatre and halls in the Tohoku region, as well as data from related businesses and individual accounts of experiences during and after the earthquake. This very detailed and comprehensive report is well worth reviewing by all those interested in theatres and halls.

For more information about the reports discussed at the JATET Forum, contact JATET at http://www.jatet.or.jp/.

Nagata Acoustics Inc.

(Tokyo Office)
Hongo Segawa Bldg. 3F, 2-35-10 Hongo
Bunkyo-ku, Tokyo 113-0033, Japan
Tel: +81-3-5800-2671, Fax: +81-3-5800-2672

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2130 Sawtelle Blvd., Suite 308
Los Angeles, CA 90025, U.S.A.
Tel: +1-310-231-7878, Fax: +1-310-231-7816

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75011 Paris, France
Tel: +33 (0)1 40 21 44 25, Fax: +33 (0)1 40 21 24 00

E-mail: info@nagata.co.jp

[ Japanese Version ]