Quietness, Comfortable Sound and Excellent Acoustics NAGATA ACOUSTICS

News 08-10 (No.250)

Issued : October 25, 2008

[ Japanese Version ]

Akasaka Sacas' Two New Performance Spaces: ACT Theater and Akasaka Blitz

by Chiaki Ishiwata

Akasaka Sacas
Akasaka Sacas

For shopping, innovative architecture, culture and fun, Tokyo's Odaiba, Shiodome and Roppongi top many local residents' and visitors' lists. Along with retailers, restaurants and other businesses, these popular gathering places are also often the location of one of Tokyo's main broadcast networks. Recently, a TV network's headquarters has become one possible key "anchor" of urban development projects.

This article focuses on the two new performance spaces in the Akasaka urban redevelopment complex built with a major TV network headquarters as one of its anchor occupants. In 1994, Tokyo Broadcasting System (TBS) completed a new headquarters on land adjacent to its previous Akasaka main location. On the site of the old headquarters, temporary structures were built and housed the rock performance space BLITZ and Akasaka Musical Theater. Now, on the same site, a new BLITZ and a new musical entertainment theater ACT have been constructed and an entire redevelopment project has surrounded the two halls on about 3.3 hectares (8 acres) of land. On March 20, 2008, the completed project, "Akasaka Sacas" held its grand opening.

The Akasaka Sacas complex includes TBS's Broadcasting Center, a 180 m. (591 ft)-tall retail and office tower named "Akasaka Biz Tower" and "Akasaka The Residence," a 21-story condominium building, as well as ACT Theater and Akasaka BLITZ. Akasaka Biz Tower connects directly to Akasaka Station via an underground shopping concourse.

Akasaka Sacas' name is a creative mix of Japanese and English. In Japanese, the word "saka" means "hill," the word "saku" means "to bloom" and, adding a few more letters, the word "sakura" means "cherry blossom." Change the "k" to a "c" and the spelling becomes "saca." Now add an "s" to create the plural, or "sacas," and you have the name Akasaka Sacas. Of course, this development is located in an area with plenty of hills and where the complex's developers planted more than 100 cherry trees along the new walkways. The redevelopment project's architect was Kume Sekkei and Obayashi Corporation served as the general contractor. Nagata Acoustics was responsible for the two halls' sound isolation and room acoustics.

<< ACT Theater >>

ACT Theater
ACT Theater
(photo by SS Tokyo Co.,Ltd.)

When Akasaka Sacas' ACT Theater opened, it proclaimed that its mission is to be a theater of "authentic entertainment." The theater has 1,324 seats and is expected to focus its programming primarily on musical theater. The seating configuration includes one balcony and the main seating area has a slope that ensures easy visibility of the stage from all seats. Visually, when the lights come up, the subdued blacks and reds of the hall's interior walls and upholstery create an atmosphere that will be attractive to serious theater-goers.

We designed the room acoustics of this hall with the expectation that the sound system will be used during most performances. To enable optimal use of the sound system, our design provides for a short reverberation.

<< Akasaka BLITZ >>

Akasaka BLITZ
Akasaka BLITZ
(photo by SS Tokyo Co.,Ltd.)

Run by the same company that also opened a BLITZ performance space in Yokohama in 2004, Akasaka BLITZ has a busy calendar of rock and popular music. Typical performances do not have seating in the main portion of the audience area and, in this configuration, the hall accommodates 1,298 persons. The hall can also be configured with up to 604 seats and has one balcony at the rear and sides of the main audience area.

A powerful sound system is a must for most BLITZ performances. The lighting and sound booth is located at the rear of the main floor, in an area that generally has some audience seating set up. At the sides of the stage, large line array loudspeakers and subwoofers were installed. The chosen speakers were Nexo Geo-T models. The vertical array system at each side of the stage combines 12 units of the 4805 module, 2 units of the 2815 module and 5 units of the CD18 subwoofer.

As we did for ACT Theater, for this hall we also created a room acoustical design that assumes the use of a sound system. Our design aimed to create a room that is acoustically "dead" and that has flat frequency characteristics across the entire spectrum from low to high frequencies.

<< Sound Isolation Design >>

Sound isolation between ACT Theater and Akasaka BLITZ, as well as sound isolation to prevent the sound of either hall from escaping into the Akasaka Sacas complex were key objectives of our work on this project.

To achieve sound isolation between the halls, our first step was to require that each facility be built as a separate structure. Both structures have a concrete slab substructure and roof poured on site while their walls are made of precast concrete. These concrete structural elements form the buildings' structural sound isolation layers. The structural design also incorporates an understanding of the somewhat impermanent nature of these halls. Like the old BLITZ performance space that stood in this same location and was replaced by these new buildings, at some future time business reasons may dictate that these halls be torn down to make room for a different building or buildings. Therefore, we designed structures that would also be easy to demolish.

Additionally, two reasons led us to implement special sound isolation structural measures for the BLITZ building. One reason is the proximity of the ACT Theater and BLITZ buildings. They are separated by just 5 m. (16.4 ft). The other reason is that BLITZ performances are expected to generate very loud sound volumes and, unless special measures were adopted, these large sound volumes would surely escape outside the concrete structure. To ensure effective sound isolation, we used a floating structural design for this hall. Also, because BLITZ audiences typically stand during performances and move in time with the music's rhythm, the floating structural design will provide the additional benefit of mitigating the vibrations that will be generated when large portions of the audience dance or stomp their feet in time with the music.

The BLITZ building's floating structural design includes floating concrete floors supported by anti-vibration elastic material for both the main floor and the stage floor, and a floating floor for the balcony using glass wool degree. For the walls and ceilings of the space we used triple layers of 15 mm. (0.6 in.) particle board held in place with anti-vibration fittings.

In addition to isolating sound generated in ACT Theater and by BLITZ performances, electromagnetic shield materials were installed in both halls. The reasons for this design element are the very near location of the TV broadcast headquarters and the large quantity of wireless microphones in use at both halls.

<< Sound Isolation Testing Using a Simulated Performance >>

When the BLITZ building completed construction, we tested the sound isolation performance level of the building by playing CDs through BLITZ's loudspeakers at sound volumes comparable to the level of a typical performance and measuring if the sound could be heard inside ACT Theater, in front of the TBS headquarters and at several locations on the site of the residential tower. Inside BLITZ, where the test sound volume reached a sound pressure equivalent of 126 dB with equalized sound that simulated a typical BLITZ performance, the amount of low frequency sound was so large that instead of simply making my ears hurt, it was loud enough that I could feel it in my chest.

At ACT Theater, where ambient noise is about 30 dB(A) and at the tested outdoor locations, where ambient noise is about 50~55 dB(A), the simulation results verified that the level of sound that can escape from the BLITZ building is insignificant enough that it becomes camouflaged by the ambient noise in these locations and cannot be heard by the human ear. Our design strategies succeeded in achieving their desired sound isolation goals.

<< For The Achievement of High Sound Insulation Performances >>

The precast concrete panels we used in this project offer excellent sound isolation properties, but they are not appropriate for situations where tiny fissures and gaps need to be sealed. Even on this project, during construction we found many tiny fissures where the steel frame comes in contact with the precast panels, and these gaps could not be fixed with sealant alone. We relied on a variety of materials, including steel sheeting, rock wool and lead sheeting, in combination with the sealant to close the many fissures.

The use of dry construction is likely to increase on future projects. When precast panels are used on a project that requires a high level of sound isolation performance, the simplest possible method for installing the panels should be determined during the project's planning phase, and during the project's construction phase the installers need to act quickly and with patient attention to detail to seal gaps that may be discovered. These activities and a system for inspecting and confirming that the contact points of the panels are sealed will make a significant contribution to ensuring that projects achieve their sound isolation performance objectives.

<< The Two Venues' Busy Calendars >>

From their first days open, both ACT Theater and BLITZ have been enjoying very busy performance calendars. Events in other parts of the Sacas complex have also contributed to a buzz of activity.

Both venues are just a few minutes' walk from Akasaka subway station in the heart of an area known for its many restaurants, nightclubs and bars, making it easy to enjoy a night out on the town that includes entertainment, dining and a few drinks as well. When in Tokyo, these halls are well worth including in your entertainment itinerary.

The Akakasa Sacas website is: http://www.sacas.net/index.html

Acoustics'08 Paris

By Marc Quiquerez

Opening lecture of Acoustics'08 Paris in the Grand Amphithéâtre of the Palais des Congrès (Paris, France) - June 30, 2008
Opening lecture of Acoustics'08 Paris
in the "Grand Amphithéâtre"
of the Palais des Congrès (Paris, France)
- June 30, 2008

From June 30 to July 4 of this year, the second ASA-EAA joint conference, "Acoustics'08," gathered over 4,000 participants from 76 countries together in Paris, France. This joint conference, thought to be the largest ever gathering of acoustical professionals, offered more than 3,500 presentations through 263 oral sessions and 167 poster sessions. The event incorporated the 155th Meeting of the Acoustical Society of America (ASA), the 5th Forum Acusticum of the European Acoustics Association (EAA), and the 9th Congrès Français d'Acoustique of the French Acoustical Society (SFA) into one joint conference, and integrated the 7th EUROpean conference on NOISE control (euronoise), the 9th European Conference on Underwater Acoustics (ecua) and the celebration of the 60th Anniversary of the SFA. More than 50 exhibitors attended, comprehensively representing all areas of acoustics, such as acoustical equipment and software, acoustical consultants and many other specialties.

Two Nagata Acoustics consultants, Keiji Oguchi and this author, attended the event. Dr. Oguchi also presented his invited paper on the acoustical design of the recently opened Shenzhen Concert Hall (Shenzhen, China). (See our November, 2007 "News & Opinions" for an article about the Shenzhen Concert Hall.)

The conference included 29 oral sessions and 16 poster sessions devoted to architectural acoustics. Within this category, the sessions addressed a wide variety of subjects, including case studies of renovations or designs of concert halls, the acoustical design and evaluation of opera houses, analysis of orchestra platforms and layouts, and sessions about historical designs and new trends, coupled-volumes acoustics, design concepts and criteria of concert halls, new measurements parameters, computer modeling and predictions, and other topics. Despite the rich diversity of scheduled programs, the sessions turned out to be a little repetitive in content. Admittedly, the very large number of presentations limited the time for in-depth discussions, and the resulting time constraint may have caused or contributed to this sense of repetition. Nevertheless, some lectures and topics held my attention and that of other attendees.

In some presentations, I noticed a strong interest in the use of sound-field microphones and B-format recordings in room acoustics measurements and the analyses of the spatial distribution of the reflections around a listener. The latter presented information that goes beyond the now commonly accepted concept of lateral fraction (LF) and inter-aural cross correlation (IACC). A. Bassuet of Arup Acoustics (New York) proposed promising analysis and results to describe the 3D spatial composition of sound in music spaces, recalling Dr. Yamazaki's 1990 study, "Measurement of spatial information in sound fields by closely located four point microphone method," in the Journal of the Acoustic Society of Japan, vol.10, no.2.

Also of great interest was the talk by T. Hidaka of Takenaka R&D Institute (Chiba Pref., Japan). Mr. Hidaka proposed a comparative survey between shoebox and non-shoebox halls through the study of Reflection Energy Cumulative (REC) curves. Nagata Acoustics' Yasuhisa Toyota introduced the application of REC curves to the professional acoustics community in 1988 and Nagata Acoustics commonly uses them as a design and study tool.


Finally, I will mention the presentation by Marshall Day Acoustics (MDA) consultants' J. Valentine and T. Scelo on the topic of the in-progress design of the Philharmonie de Paris concert hall. Nagata Acoustics serves as acoustical consultant to the architect on this project (in peer association with MDA). (See our May, 2007 "News & Opinions" for an article devoted to the Philharmonie de Paris project.). The MDA presentation drew a large audience who expressed avid interest in the design presented.

Kabuki Revivals: Heisei Nakamura-za and a New Kabuki DVD Series

by Makoto Ino

<< Heisei Nakamura-za >>

View from the BUTAI (Stage)
View from the BUTAI (Stage)

In late September, I attended a Japan Theatre and Entertainment Technology Association tour of Tokyo's Heisei Nakamura-za. In the Japanese language, the character for "za" literally means "seat," but when appended to the name of a family of actors or a genre, such as "Kabuki," the suffix takes on the meaning of "theater." Heisei Nakamura-za is a temporary Kabuki theater, built and run by the Nakamura Kabuki troupe, where modern building materials and ingenuity combine with traditional Japanese theater design.

Heisei Nakamura-za is a short, five- or six-minute walk from Asakusa Station, located directly behind the famous Senso-ji Temple's main building. (The Kaminari-mon gate of this temple, with its huge red lantern suspended above the gate's entryway, is a stock photo of tourist brochures about this "shitamachi" section of Tokyo.) In keeping with the theater's temporary nature, the theater's exterior "skin" is heavy-duty tent canvas.

Inside the theater, the floors of both the stage and the audience seating area have frames made of interlaced square and round aluminum pipe topped with plywood. Kanai Scene Shop, Ltd., Kabuki's traditional purveyor of stage backdrops and other interior theater construction needs, designed the flooring system and, even though the floor frame sits on construction scaffolding, the joints are so tightly and exactingly put together that there is not even a hint of a sway or a creak anywhere.

On the theater's interior walls, Kanai Scene Shop used traditional Kabuki stage-backdrop distemper paint and rock pigment materials and techniques to create the look of natural wood. In addition, rows of Edo-era-style paper lanterns hang above the main level's side-box seating, above the side balcony and at the rear of the theater, completing the visual ambience of a Kabuki theater of pre-modern Japan.

<< The "Essence" of Kabuki DVD Series >>

To learn about the history of Nakamura-za, I turned to a new DVD and book series published by Shogakukan. The four volume series, issued exclusively in Japan, has the title "Kabuki no Iki." The "iki" of the series title refers primarily to the unique mix of melodrama, humor and heart-racing action artistry which inform the Kabuki genre, and secondarily has meanings of "essence" and "life-breath." The DVD series contains a vast amount of information and actual performance footage.

From the Shogakukan series, I learned that the theater's history dates back to 1624, during the reign of Shogun Tokugawa Iemitsu, the third Tokugawa ruler and grandson of Japan's great Shogun Tokugawa Ieyasu, who unified Japan into one country. Kanzaburo Saruwaka, head of the Saruwaka acting troupe, which later changed their actors' stage surname to Nakamura, petitioned Shogun Iemitsu's government and obtained the right to build the original Nakamura Kabuki theater in Edo. According to the Shogakukan series, the original Nakamura Kabuki theater is considered the starting point of Japan's still vibrant Kabuki genre.

Knowing the history of Kabuki and own it's theater led me to the thought-provoking realization that when I sit and watch a Kabuki performance in the Heisei Nakamura-za, I am experiencing the same entertainment and surroundings that residents of Edo enjoyed 400 years ago. The new Kabuki DVD series includes recordings of 58 favorite's and climax scenes, in which the chanters' vocalizations enhance the climactic moments of a Kabuki play's third act. I encourage our readers to watch these scenes before you next attend a live Kabuki performance at Nakamura-za or at another venue during one of Kabuki's international tours. Familiarity with favorite's and climax scenes will enhance your enjoyment and appreciation of the live performance.

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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Los Angeles, CA 90025, U.S.A.
Telephone: (310) 231-7818
Fax: (310) 231-7816

E-mail: info@nagata.co.jp

[ Japanese Version ]