Quietness, Comfortable Sound and Excellent Acoustics NAGATA ACOUSTICS

News 10-12 (No.276)

Issued : December 25, 2010

[ Japanese Version ]

Shibuya City's Owada Cultural Center Opens

By Nobuhiko Hattori

Cross sectional view of Owada Cultural Center
Cross sectional view of Owada Cultural Center

In November, 2010, Shibuya City's multipurpose Owada Cultural Center opened to the public. Shibuya has a reputation for shops and eateries popular with Tokyo's younger crowd. The new cultural center, with its two halls (one for western music and one for traditional Japanese performing arts), a planetarium (re-opening this local educational facility after a 9-year closure), a nursing school and a public health clinic, aims to be a destination for residents of all generations. In addition to being a cultural center, the building houses a diverse combination of educational, training, public health and welfare services and facilities.

Owada Cultural Center uses a site located between two high-rise buildings, the 40-story Cerulean Tower Tokyu Hotel and the 21-story Shibuya Infoss Tower. The dome-shaped ceiling and roof of Owada Cultural Center's top floor, designed for the center's planetarium, adds a new, easily recognizable landmark to this part of Shibuya's skyline. Until 1997, Owada Elementary School stood on the site now used by the cultural center. When the cultural center recently held its opening ceremonies, the guests included both Shibuya City representatives and many attendees who graduated from this school as young children.

Layout of the 6th floor
Layout of the 6th floor

<<Project Overview >>

Owada Cultural Center has 12 stories above ground and 3 stories underground. Its Sakura Hall has acoustics intended primarily for classical music performances. The center second hall, named Densho Hall, has an interior design and acoustics intended for traditional Japanese performing arts. In addition, the center has 5 music practice rooms, the planetarium, two floors for fashion design technical training, a nursing school, diagnostic health facilities, a library, and spaces for children's activities.

A joint venture of NTT Facilities and Nissoken Architects designed the cultural center and Taisei Corporation built it. Nagata Acoustics' participation focused primarily on the acoustical room design and sound isolation and vibration mitigation design for the two halls.

<<Sound Isolation Design >>

The plans for this mixed use building designated the lower floors for facilities that will be used by children and their parents, including both classroom and activity room areas. The library is also on the second floor. The upper floors have spaces for the nursing school, the fashion design training workshops and other classrooms and conference rooms. In between the lower and upper floors of the building, the two halls occupy the middle floors. To provide sound isolation between the halls and the floors above and below them, we installed a layer of anti-vibration rubber material and 3 layers of 12.5 mm. (0.5 in.) thick gypsum board.

As a cost-saving measure, for Densho Hall, we limited our use of anti-vibration and sound isolating structural additions, implementing these elements primarily in the stage. On the level above this hall, we installed a glass-wool floating floor. On the floor below, where there are 5 music practice rooms, we adopted an anti-vibration and sound isolation structural design to isolate these rooms.

<<Sakura Hall Room Acoustical Design >>

Sakura Hall stage

Sakura Hall interior seen from stage
Interior seen from stage

Sakura Hall seats an audience of 735 and is a multipurpose hall with acoustics designed primarily for the performance of classical music. The hall can be configured with an orchestra pit and a movable proscenium stage opening, and we equipped the hall's stage with sound reflection panels for use during classical music performances.

This hall's basic shape is a shoebox configuration, with a 15 m. (49 ft) high ceiling, a 17 m. (56 ft) wide audience seating area and one balcony. We installed random ribbing along the side walls of the first floor audience seating area to promote sound diffusion. On the balcony level, we placed an eave-like sound reflecting element along the upper portion of the side walls to enhance secondary sound reflections.

Inspired by our acoustical need for eaves along the upper portion of the balcony's side walls, the architectural team created a design that extends the eave-like decorative element from the walls of the stage along the entire length of the balcony's walls. As a result, the interior design and the acoustical requirements together achieved an integrated visual appearance and hall's acoustical objectives.

The stage's side sound reflection panels can be stored above the ceiling. At the rear of the stage, we installed fixed sound reflection panels. The sound reflection panels at the rear of the stage double as an anti-vibration and sound isolating element of the hall. It fixed panels contain air supply vents for the hall's air circulation system. Additionally, we designed "L" shaped pieces that we added at the top of the stage's side and rear sound reflection panels to minimize the possibility of gaps between these sound reflection panels and the ceiling sound reflection panels.

With the stage sound reflection panels in place, Sakura Hall's reverberation time measures 1.9 seconds (in a fully occupied hall, at 500 Hz). With the proscenium and stage curtain in place, the reverberation time measures 1.2 seconds (under the same conditions). The significant difference of 0.7 seconds between the hall's two configurations will make this hall eminently adaptable to the needs and expectations of the artists and patrons of a variety of classical music and other performing arts genres.

<<Densho Hall Room Acoustical Design >>

Densho Hall has a seating capacity of 345 persons and is a multipurpose hall with acoustics designed primarily for traditional Japanese performance genres (which typically include the use of traditional musical instruments). The stage opening can be varied between a width of about 9 m. (30 ft) and 11 m. (36 ft). The stage has a depth of about 11 m. (36 ft). We provided small risers and sound reflection panels for use with various instruments and performance configurations.

Densho Hall
Densho Hall

The audience seating area of Densho Hall measures 12 m. (39 ft) wide and 16 m. (59 ft) deep. It has a single, sloped floor with "sajiki" seating at the sides. A "hanamichi" runway can be added at the side for Kabuki plays.

Japan's traditional performing arts genres include a variety of vocal styles and instruments that have differing acoustical needs and optimal performance space conditions. For example, "naga-uta", a vocal style accompanied by the shamisen, requires a space with good reverberation and sound reflections for the unamplified vocalist. Also, musicians of traditional stringed instruments often say that they prefer a stage environment where they can hear the sound of their instruments reflected back to them from the rear wall of the auditorium.

Because of these needs and preferences, in addition to having this hall's ceiling and side walls be sound reflecting surfaces, we specified that all but a portion of the rear wall also be a sound reflecting surface. For the portions of the side walls and rear wall that are at the same height as the audience seating level, we prevented the possibility of overly strong sound reflections by installing clapboard siding to diffuse the sound.

Clapboard wall siding
Clapboard wall siding

Densho Hall's reverberation time measures 1.0 second when configured with the stage curtain (in a fully occupied hall, at 500 Hz). When the stage has the sound reflection panels set up, the hall's reverberation time increases to 1.2 seconds.

<< Owada Cultural Center in Operation >>

Since Owada Cultural Center's November opening, the planetarium that planners expected would attract a strong flow of visitors has proved its popularity. The two halls' opening events included local talent, such as a dance performance by children who live in Shibuya City and a traditional Japanese music performance by city residents. On weekends, seniors come to the library and young families energetically participate in active learning games and projects in rooms on the lower floors.

The cultural center just recently began serving the diverse needs of different age groups in the community. Naturally, I am most strongly interested in how the two halls will be used. The center intends to maximize rental use of the halls and limit center-sponsored performing arts programs. In addition to this practical strategy, Owada Cultural Center might consider developing themed programming that connects the parts of the center that residents typically use on a daily basis with performances in the two halls. Also, hall sponsored programming for Sakura and Densho halls would take advantage of the center's very convenient Shibuya location and attract audience patrons from other parts of Tokyo and beyond. I hope that, in the future, the center's administrators will decide to proactively add hall-sponsored programming to its halls' calendars.

The Web site for Shibuya City's Owada Cultural Center can be found at http://www.shibu-cul.jp/

Acoustical Building Materials from Around the World: Part 3 - Perforated Panels

By Dr. Keiji Oguchi

Example of panel with square perforations from a French manufacturer
Example of panel with square perforations
from a French manufacturer

In this article, I will introduce two interesting developments in perforated panels. In Japan, acoustical consultants often specify the installation of perforated panels as sound-absorbing wall or ceiling finishes. Typically, perforated panels consist of plywood board, gypsum board, metal or other material with round perforation holes. Suppliers sell ready-made perforated panel products with a range of perforation diameter and spacing specifications.

Outside of Japan, I've sometimes seen the use of gypsum board with square perforations. To some eyes, round perforations give the impression of a more custom-made finish, and therefore may be considered a more upscale product. Nowadays, advances in laser perforating technologies also make it possible to create any perforation shape.

TOPAKUSTIK® panel (from website)

One unique method to produce a perforation panel is to use a combination of separately fabricated front and rear panel sections. The front section has grooves cut into a thick panel so that they partially penetrate the board. This front panel is combined with a rear panel section that has partially perforated grooves cut at a different angle than the grooves cut into the front panel section. The grooves on each side of the panel system penetrate more than halfway through the panel and, as a result, where the front and rear grooves intersect, create perforations through the panel. Depending on the angle of the intersections of the partial front and rear grooves, the perforations through the panel take the shape of a different four-sided shape, such as a square, parallelogram or rhombus. Also, by pairing a grooved front panel with a rear panel that has round perforations, the grooves of the visible front section panel can have less open surface area than would a standard perforated panel with round holes.

TOPAKUSTIK panels used in a studio sound control room
used in a studio sound control room

In March, 2010, I visited n'H Akustik + Design AG, the Swiss company that pioneered the design and manufacturing of these panels under its TOPAKUSTIK® brand. The company gave me an in-depth tour of their facility and showed me the variety of dimensions they keep in stock for their front panel groove widths and spacing, and for the diameters and depths of perforated rear panels.

Yasuragi panels used on the walls of a meeting room
Yasuragi panels
used on the walls of a meeting room

In the April 2003 issue of this News & Opinions Newsletter, I discussed my different concept for minimizing the appearance of the holes in perforated panels. The visual appearance of my concept bears some resemblance to the grooved front panels I discussed above. I am pleased to report that my concept has been developed into the product "Grooved Yasuragi Acoustic Panels".

For more information about these products, visit the following Web sites: for TOPAKUSTIK® , visit http://www.topakustik.ch/en, and for Yasuragi Acoustical Panels, visit http://www.hky.co.jp/, in Japanese.

New Kabuki-za Theatre Begins Construction

By Toshiko Fukuchi

New Kabuki-za Theatre exterior (rendering)
New Kabuki-za Theatre exterior (rendering)

The Kabuki-za Theatre, a well-loved architectural landmark and cultural destination in the Ginza section of Tokyo, closed its doors on April 30, 2010. After the theatre's closing, preparations began for the construction of a new theatre and high-rise building on the same site. Demolition crews spent months tearing down the old structure and preparing the location. On October 28, 2010, representatives marked the official construction start of the new, fifth generation of the Kabuki-za Theatre.

<<The 5th Generation Kabuki-za Theatre Project Participants >>

Kabuki-Za Co., Ltd and a Specific Purpose Company which Shochiku Co., Ltd formed fund the fifth-generation Kabuki-za Theatre project. Mitsubishi Jisho Sekkei Inc. and Kengo Kuma & Associates created the architectural design. Shimizu Corporation is the general contractor.

New Kabuki-za Theatre interior (rendering)
New Kabuki-za Theatre interior (rendering)

Nagata Acoustics began participating on the project during the conceptual design phase, under contract to Mitsubishi Jisho Sekkei Inc. Our scope of work includes acoustical consulting services for both the project's architectural acoustics and the sound isolation design and vibration mitigation.

<< Project Programming >>

The 5th generation Kabuki-za Theatre project's programming defined four categories of objectives for the project.

1. Goals for the theatre:
  * Provide for the core use of the theatre as the new Kabuki-za.
  * Establish a theatre to the standards of a multi-genre cultural destination by
    - Upgrading the performance reproduction capabilities and other theatre equipment;
    - Creating a space that promotes the art of Kabuki and symbolizes the art of Kabuki to the general public;
    - Maximizing accessibility within the theatre, including increasing individual seat size and the number of restrooms.

2. Infrastructure and local access goals: Improve accessibility from nearby underground mass transit (subway) stations to ground level.

3. Landscape goals: Add greenery to the site.
  * Build a rooftop garden.
  * Plant trees and add other landscaping around the building.

4. Environmental goals: Adopt and implement environmental load reduction measures.

<< The 1951 Kabuki-za Theatre and the New, Fifth Kabuki-za Theatre's Progress >>

When completed, the new Kabuki-za Theatre will be the fifth Kabuki-za Theatre built on the same site. The first Kabuki-za Theatre at this Ginza location opened in 1889. The recently demolished fourth-generation Kabuki-za Theatre was repaired and renovated in 1951 after sustaining damage during World War II. Architect Isoya Yoshida designed the 1951 renovation, which included changing the theatre's coffered ceiling to one that used traditional Japanese ceiling ribs and "saobuchi" battens, and that, more significantly from the acoustical perspective, rose upward in height from the stage toward the rear of the theatre. This ceiling configuration seems to have been responsible for improved acoustics in the 1951 building.

The new, fifth Kabuki-za Theatre will have close to the same seat count as the fourth Kabuki-za Theatre and will preserve the look and atmosphere of the fourth Kabuki-za Theatre. Nagata Acoustics will ensure that the new theatre has acoustics that rival or exceed the acoustics of the old, fourth-generation Kabuki-za Theatre. Our upcoming activities on the project include building a 1/10 scale model and using the model to perform acoustical testing of the new theatre's interior architectural design.

Currently, and for the next few months, the on-site construction crew will build the underground portion of the building. After next year, the project will progress to building the above-ground portions of the building. The Kabuki-za Theatre project will complete in the spring of 2013. The opening will surely be a gala event that no-one will want to miss.

The Kabuki-za Theatre's home page (in Japanese) is http://www.kabuki-za.co.jp/.

For more recently constructed halls, sound reflecting panel systems now include stage lighting and stage entrance and exit doors as part of the sound reflecting panel system. Recent designs also use innovations such as panels that can be folded instead of separated for storage and ways to reduce the clearances needed between panels to as little as 100 mm. in order to reduce the quantity and size of gaps in the sound reflecting panel system.

"Organ Entertainment 4"Concert Planned

By Toshiko Fukuchi

On April 2, 2011 (Sat.), at 1:30 p.m., "Organ Entertainment 4" will be performed at Sumida Triphony Hall. The program will again feature organist Ryoki Yamaguchi.

A companion event will be held one day earlier, on April 1, also at 1:30 p.m. This event will include a video about the internal mechanism of pipe organs and a lecture-concert featuring Makiko Arai.

Cherry blossoms will be in bloom and Kinshi-cho's 634 m. Tokyo Sky Tree is expected to be completed and open to the public. If you'll be in Tokyo at the start of April, this will be excellent timing to enjoy Triphony Hall's pipe organ and spend time in Kinshi-cho as well.

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

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

(Paris Office)
75, avenue Parmentier
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 ]