Quietness, Comfortable Sound and Excellent Acoustics NAGATA ACOUSTICS

News 07-09 (No.237)

Issued : September 25, 2007

[ Japanese Version ]

Suntory Hall Re-opens After Its Renewal Project

by Makoto Ino

Interior of the Large Hall <br>after the renovation
Interior of the Large Hall after the renovation

Suntory Hall first opened its doors in October 1986. Last year, after the hall celebrated its 20th anniversary, the hall underwent a major renewal project, reopening on September 1, 2007.

Suntory Hall's first appearance in the Nagata Acoustics monthly newsletter coincided with the newsletter's very first issue, dated January 1988. At that time, our company founder, Dr. Minoru Nagata, focused the article on Suntory Hall's first year, writing about the hall's reputation with performers and audience during its inaugural year and also listing a bibliography of acoustical engineering articles written about Suntory Hall shortly after the hall's opening. In the months and years since the first issue of the newsletter, Suntory Hall has frequently appeared in these pages.

<< Some Pre-renewal Suntory Hall Memories >>

For Nagata Acoustics, Suntory Hall represented a turning point in the application of research on sound reflections to hall design, and the success of Suntory Hall proved the merit of our acoustical design methodology, which places importance on the characteristics of a hall's sound reflections. Dr. Nagata followed Suntory Hall's rise to prominence as a world class hall like a proud parent and has always retained a strong professional attachment to this milestone project.

In June 1988, for our newsletter's sixth issue, Dr. Nagata wrote an intriguing article about Suntory Hall entitled "Does a Hall's Sound Change?" When the hall had been in operation for one-and-a-half years, comments arose from both performers and concert patrons that something about Suntory Hall's acoustics had changed. I remember experiencing this sense of something changed when I attended a concert at Suntory Hall a few years after the hall opened and after a hiatus in my concert attendance there. My personal evaluation was that the hall's sound now had more clarity and subtlety than before, and I had a greater sense of the pleasurable way sound flows through the large space until it eventually vanishes. Dr. Nagata closed his article on whether hall sound changes by writing, "the good news is that the changes that occur are always positive." The experience of this positive change in the hall must have been a rewarding sensation.

<< Overview of the Suntory Hall Renewal Project >>

Now, 20 years later, the hall has preserved its fine acoustics through the recently completed renewal project. The project's key driver and leader, Suntory Hall Associate Chief Manager Yotaro Takeda says that planning activities for the project began about five years ago. Last autumn, the hall held its 20th anniversary festivities and brought them to a successful close; then, on April 1 of this year, the hall shut down completely and the renewal work went into full swing.

The same companies that performed the original work for the hall were brought back for the renewal project. Yasui Architects & Engineers, Inc. prepared the architectural plans and design, and Kajima Corporation was responsible for the renovation construction. Nagata Acoustics consulted on the acoustics and designed the new sound system, and Fuji Sound Co., Ltd. installed the sound system.

The main objectives of the renewal project included replacement of the stage mechanisms and building equipment, refurbishing worn aesthetic elements of the hall, increasing the restroom facilities and implementing universal design features to provide improved access for wheel chairs and patrons with other special needs. Additions were made to the stage-floor risers of both the Large and Small halls to accommodate a wider range of performance formats.

Sidewalls of the stage of the Small Hall
Sidewalls of the stage of the Small Hall

In the Large Hall, the walls' wood paneling was replaced, the ceiling painted and both the upholstery and the cushions of the audience seating were replaced. For all of these Large Hall renovations, the same materials and production methods that were used when the hall opened 20 years ago were used again in order to ensure that the renovation work would not affect the hall's acoustics.

In the Small Hall, changes to the sidewalls of the stage make them able to be manually positioned to enhance the stage with stage wings when needed. We maximized the value of this part of the renovation by designing the sidewall panels so that they can be set at any desired angle and used as sound reflection panels as well as to create stage wings.

<< Sound System Renovations >>

The Large Hall's old main cluster speaker
The Large Hall's old main cluster speaker

The new main cluster line array speaker
The new main cluster line array speaker

When Suntory Hall was under construction in the 1980s, the value of having a sound system in a concert hall was still relatively unrecognized. Some project participants even said that there was no reason to install loudspeakers in a concert hall. By contrast, nowadays, lecture concerts and other educational programming have become common concert formats, and the quality of amplified speech is an important element in successful production of these kinds of programs. I gave particular attention to this need in planning and designing the loudspeaker replacement systems for the Large and Small halls.

The two goals of replacing the Large Hall's loudspeaker system were to obtain a level of speech intelligibility that ensures ease of comprehension by the audience and, at the same time, to deliver amplified sound imbued with a dignified quality that appropriately complements the hall's acoustics. We began the loudspeaker selection process by following advice once given to us by Suntory Hall's founder, the late Mr. Keizo Saji. When Nagata Acoustics began acoustical design of Suntory Hall, it was a great challenge for us for we had never done the acoustical design of a vineyard configuration concert hall. Mr. Saji encouraged us by saying "Just go for it." Remembering this forward-looking attitude of trying anything, we brought in all the loudspeaker choices and "just had us a listen."

For the renovation project we again assembled the candidate loudspeakers from several manufacturers and brought them into the Large Hall to evaluate each one. The two finalists in our selection process represented two different array technologies by two different U.S. manufacturers. One was EAW's coaxial AX series, which uses a methodology that moves the air through a common horn, delivering very clear, crisp sound. The other finalist, the XLVC series by Electro-Voice (E.V.), uses the technology of combining multiple loudspeaker units end-to-end in line arrays, an approach that produces sound characterized by very high intelligibility. We surveyed the preferences of several dozen individuals connected with Suntory Hall and the project and discovered that while some acoustical professionals tended to prefer the coaxial type of loudspeaker, everyone else tended to favor the line array type of loudspeaker. After debating the merits of the two loudspeaker systems, we aligned our decision with our goal of ensuring a high level of speech intelligibility and selected the line array loudspeakers.

In the Large Hall, the main cluster can be raised up into the ceiling to hide it from sight. We installed additional in-ceiling and above-ceiling loudspeakers as a supplement to the main cluster so that the loudspeaker system can be effectively used while the main cluster is in its raised position. I performed the initial configuration work to program the system's settings, after which the company responsible for on-site sound technician needs, NHK Art Inc., completed the fine tuning. The result is that we achieved extremely high quality intelligibility for amplified sound in the Large Hall. The Large Hall's main cluster was needed for the hall's 20th anniversary celebration concerts and events, which we knew would include frequent speeches in-between performances, so we obtained the approval of Suntory's leadership team to install this equipment during the summer of last year when the hall had a scheduled maintenance closure, in advance of the actual start of the renovation project.

In our renovation plan for the Small Hall, we gave careful consideration to the programming direction of Suntory Hall's President, Mr. Nobutada Saji, who aimed to have the refresh and renewal project be an opportunity to increase the hall's appeal with younger audiences. To enhance the ability to present recorded media to this demographic, we installed a full hi-vision video projector and greatly increased the number of loudspeaker units in the Small Hall to enable the reproduction of 5.1 channel surround sound from DVDs and other sources. Given the serene interior of the Small Hall and the objective of upgrading this hall's sound system, we chose the German company d&b audiotechnik's Ci series and E series loudspeakers for this part of the renovation.

With the reopening of Suntory Hall, Mr. Saji passed the helm to a new hall president, Mr. Tsuyoshi Tsutsumi, the accomplished professional cellist and chancellor of Toho Gakuen School of Music. With the renovations done and Mr. Tsutsumi in charge, I have full confidence that Suntory Hall will fill its calendar with inviting and exciting programs for all ages, from children to seniors. I look forward to seeing my music-loving friends, acquaintances and associates at Suntory Hall again soon.

Chiba City's Mihama Culture Hall

by Akira Ono

Exterior of Mihama Culture Hall
Exterior of Mihama Culture Hall

Mihama Culture Hall opened on July 1 in Chiba City's Mihama Ward. The hall project was part of a city-wide renewal construction project in all of Chiba City's wards.

Mihama Ward, with its coastline along Tokyo Bay, is the Chiba City ward closest to neighboring Tokyo. The entire ward sits on reclaimed land and its man-made origins have been accompanied by a focus on urban development planning. In the environs of the Mihama Culture Hall site, many multi-dwelling skyscrapers fill the landscape in orderly rows, and a primary goal of the new hall is to provide a center the ward's resident to use and enjoy.

A consortium of Koizumi Atelier & Partners, Coelacanth and Associates, and Murai Architect Design Office designed Mihama Culture Hall. A joint venture of Okumura Corporation and Asahi Construction Corporation served as the general contractor.

<< The Project's Unique Interior "Zoning" Approach >>

This project combines the two objectives of a cultural center and a public health and welfare center under one roof. When planning a mixed-purpose facility such as this one, where the administration, operations and people who will use the two different functionalities are completely independent of one another, the architectural plans usually physically separate the hall wing from the health and welfare wing. Typically, a layout design technique known as "zoning" is adopted, and the floor space for each set of functionalities flows independently, either in horizontally adjacent layouts or zones separated vertically into exclusive locations on different floors. In a building designed with zoning, the people using the facility for one purpose rarely, if ever, cross paths with the people using the facility for its other purpose.

By contrast, the Mihama Culture Hall project's architectural team, led by Mr. Masao Koizumi, adopted an approach they called "fusion architecture." Instead of creating specialized, autonomous areas, the building's layout intentionally causes people engaged in different kinds of activities and objectives to come into contact with each other, so that they experience their proximity and an awareness of each other in the natural course of using the facility, and the facility has a more unified character. Moreover, the implementation of the fusion concept goes beyond simply placing spaces intended for diverse users near each other, because the concept includes defining "zones" based on commonalities in the kinds of work done in specific spaces and in the parts of the day when the spaces will be used.

The unique zoning approach implemented by the Mihama Culture Hall architectural team grouped together administrative-type office space and conference rooms expected to be occupied by workers during daytime hours. Another zone comprises the building's two halls and support rooms together with the heath and welfare center's rooms for volunteer activities, which will be used mostly in the evening hours and mostly by local residents not formally employed in the building. The building's "zoning" is based on these two groupings and divided by floor. As a result, health and welfare volunteers who come to the hall cross paths with people coming to the hall to attend a performance and patrons of plays and concerts see volunteers contributing their hours and skills to community-related health and welfare activities.

<< Mihama Culture Hall's Two Halls >>

Main Hall's foyer viewd through the passageway
Main Hall's foyer viewd through the passageway

Main Hall
Main Hall

Music Hall
Music Hall

Mihama Culture Hall has a 354-seat Main Hall and a 152-seat Music Hall. The two halls are located at opposite ends of the building. At first glance this placement may seem inconvenient for hall operational personnel who must come-and-go between the two halls. However, the halls' foyers are connected by a light-filled lobby-like passageway that enables both foyers to be kept in view and makes the comings and goings of hall personnel pleasant and efficient. In addition to the two halls, Mihama Culture Hall has a rehearsal room built with a sound and vibration-isolating structure and two studios as supplementary cultural facilities.

The Main Hall is designed primarily for events that use amplified sound, such as theater productions, dance concerts, popular music concerts, lectures and symposiums. This multipurpose hall has a proscenium stage and, at the request of the client, Chiba City, we focused our acoustical design emphasis on theatrical use of the hall. Instead of installing suspended, retractable sound reflection panels from overhead stage batons, we provided only a simple set of sound reflection panels that can be set up when needed. The hall's calendar already includes a number of professional classical music performances, and I have some doubt as to whether the current on-stage sound shell apparatus will prove satisfactory for these kinds of performances. At some future time, Chiba City may need to rethink its decision regarding the stage sound shell.

The smaller Music Hall has a shoebox configuration and is finished simply with white stucco walls. The distribution of sound reflections and delay time to this audience seating area is controlled by the wave-like shape of the hall's ceiling and by the sidewall design. Each sidewall has four rows of horizontal, slightly curved, almost fin-like shallow ledges. The sections of vertical wall between each horizontally protruding shallow ledge and the angle of these vertical surfaces also contribute to controlling the delay time and distribution of sound reflections.

<< Acoustical Characteristics of the Two Halls >>

The Main Hall has a spatial volume of 3,200 cu. m. (113,006 cu. ft) and a reverberation time of 1.4 seconds when the stage curtain is in use and 1.5 seconds with the simple sound reflection panels deployed. The Music Hall has a spatial volume of 1,500 cu. m. (53,000 cu. ft) and a reverberation time of 1.4 seconds. This hall does not have apparatus to vary the reverberation time. Both halls' reverberation times are for measurements at 500 Hz.

<< The Facility's Management and Operations >>

The project's construction cost about 2.6 billion yen (US$23 million or 17 million euro). The annual maintenance and operational fee that will be paid from tax revenues is estimated at more than 100 million yen (US$880,000 or 640,000 euro). Management and operational responsibility for the facility has been entrusted to the private-sector company Artwind.

For Mihama Culture Hall's opening concert, entitled "Mihama Breezes," both numerous well-known entertainers and local amateurs recruited through a series of auditions participated. The event heralded the direction of this new facility, where local residents will be performers as well as audiences. As their affection grows for the new facility, more residents will surely volunteer, not only to appear on stage, but also to participate in the health and welfare initiatives taking place side by side with the performing arts. I look forward to hearing about the activities and culture that will be nourished in this new venue.

The Chiba City Mihama Culture Hall website is http://www.mihamahall.jp/.

Nagata Acoustics Inc.
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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[ Japanese Version ]