Title means "Quietness", "Comfortable Sound" and "Excellent Acoustics"

Nagata Acoustics News 03-07 (No.187)
Issued : July 25, 2003

Richard B. Fisher Center for the Performing Arts Opens at Bard College (New York)

by Yasuhisa Toyota

Fisher Center at Bard College Exterior
On April 25, 2003, Bard College, in Annandale-on-Hudson, New York, held a gala opening for the 900-seat, medium-scale, multipurpose hall that is the key performance facility in the school's new Richard B. Fisher Center for the Performing Arts. The opening marked the completion of Nagata Acoustics first hall project in the United States.

Bard College is located about 150 km (90 miles) north of Manhattan on the east bank of the Hudson River in the small, college town of Annandale-on-Hudson in the picturesque Hudson Valley. Founded in 1860, Bard College has a long tradition as a small, progressive liberal arts college and continues to uphold a strong dedication to the humanities and arts.

<< The Annual Bard Music Festival >>

Since 1990, the Bard College campus has been host to an annual summer music festival that is now in its 14th year. Prior to this year, the festival was held in a temporary tent facility set up for the festival, and the festival's programming focused on orchestral music, solos and chamber music, with about 10 to 12 concerts and a number of lectures being the main festival offerings.

Starting with this year, the festival occupies its newly built, permanent home for the first time. With the change to the new venue, the festival's programming already demonstrates a broader range of performance genres, expanding in scope to include operas and dance performances as well as its usual range of music concerts.

Considering the size of the nearby college town and the small size of Bard College, the annual Music Festival's international renown may seem disproportionately large by comparison. But this music festival's strong reputation stretches worldwide, due in large part to its unique programming formula. Each year, the festival dedicates its entire programming to a focus on a single composer, not only exclusively putting the composer's music in its concert programming, but also using lectures, film and other ways to delve deeply into the composer's life and the historical circumstances in which the composer lived. This academically inclined approach has found much favor and acclaim among erudite New Yorkers, who also appreciate the opportunity to enjoy the Hudson Valley's cool respite from the hot New York City summer weather.

<< College President Leon Botstein's Vision >>

At the helm of the annual Bard Music Festival is Mr. Leon Botstein, president of Bard College. Mr. Botstein also serves as Music Director and Principal Conductor of the American Symphony Orchestra, which performs its main subscription seasons at Lincoln Center's Avery Fisher Hall.

The new performing arts center is the brainchild of Mr. Botstein. It creates for the college both a venue for performing arts instruction and performances, and, through the annual Music Festival, aims to increase Bard's ability to draw students and visitors to Bard and the Hudson Valley region. In the words of Bard College's website, "the arrival of this extraordinary building marks a transforming event in the cultural life of the college and the region--a moment in which theater, dance, music, and opera have found a stunning new showcase in New York's historic Hudson Valley."

To implement Mr. Botstein's vision, the center's construction project was supported by a budget of $62 million, including about $5 million of funding invested by New York State. Under Mr. Botstein's direction, the center's 900-seat Sosnoff Theater was planned and designed as a multipurpose hall for both concert and opera performances.

<< Master Architect Frank O. Gehry >>

Master Architect Frank O. Gehry designed the Richard B. Fisher Center for the Performing Arts. Mr. Gehry is also the architect with whom Nagata Acoustics is working on the Disney Concert Hall in downtown Los Angeles. The earlier opening of the Richard B. Fisher Center for the Performing Arts makes it a harbinger for the Disney Concert Hall project that is still in progress.

<< Acoustical Characteristics of this Multipurpose Hall: A Focus on the Acoustic Shell >>

Hall Interior
Even though the new hall at Bard needed to be a multipurpose hall, this did not mean that there was any willingness to compromise on the hall's acoustical characteristics, which aimed for world-class concert hall acoustics. To this end, from the start of the acoustical design work, we focused on the highly significant stage area and, in particular, on the design of the stage's removable acoustic shell.

To enable performances by large orchestras, we defined a stage with a large area and we also made sure that the ceiling above the stage would have adequate height. Our approach was to design the orchestra pit so that it can be raised to stage height for concert use. As a result, so that the stage used for concert performances protrudes as much as possible towards the audience seating area and has a higher stage ceiling height than was formerly possible in a multipurpose hall.

In addition, to obtain effective sound reflections for the entire range of low-to-high frequency sound, a key aim of the design was to maximize the mass of the acoustic shell. But we were also working under an obligation to contain construction costs, and a compromise plan was implemented regarding the time and labor necessary for the acoustic shell's set-up and storage. Setting up the acoustic shell requires five or six people and five-to-six hours of work.

<< The Hall's Acoustical Characteristics >>

The hall's reverberation time (at 500 Hz) is:

The hall's HVAC system noise level is controlled to lower than NC-15 throughout the audience seating area.

<< Preparing for Mahler as the Opening Concert >>

The hall's opening concert program featured Mahler's Third Symphony, a composition that requires a large orchestra of about 100 members. From the perspective of the hall's seating capacity (about 800 seats for the concert hall configuration), a chamber orchestra-sized ensemble could fairly be considered the ideal size performance group for such a space. Mr. Botstein's decision to push the limits of the hall's capabilities for the inaugural concert was in keeping with his character as music director. (In the words of the hall's website: "The Frank Gehry-designed center ... inspires risk-taking and provocative programs.") At the same time, this presented a large challenge to us at Nagata Acoustics.

In the post-construction period, through the acoustical tuning sessions that involved various sizes and kinds of ensembles, followed by the opening concert rehearsals and the opening performance, our stress levels stayed unabatedly high. Thankfully, the result was a Mahler symphony of unequivocal and resounding success. Even the moments of large volume fortissimo that were our greatest concern did not take the sound to the point of acoustical saturation; the sound of each of the instruments on stage could be heard with distinct clarity. The delicate pianissimos also reached every seat in the hall.

Solo and chamber music concerts followed the opening concert, and each demonstrated the new hall's acoustical capacity and versatility. The hall received rave reviews from the New York Times and other respected publications.

<< Bard SummerScape 2003 >>

On July 25th, as part of this year's Bard Music Festival, Sosnoff Theater will have another gala opening with its opera-configuration performance. This year, the festival highlights Czechoslovakian composer Leos Janacek, and his opera "Osud" (Fate) will be performed. Of particular note for the opera configuration is the stage design, which was designed by master architect Frank Gehry.

Sapporo Convention Center Opens

by Masaya Uchida

Sapporo Convention Center
Main Hall (left) and Conference Hall (right)
(©Hokkaido Nikken Sekkei)
As part of Sapporo City's efforts to become a choice location for convention holders, this capital city of Hokkaido (Japan's northern-most main island) has been investing in the construction of an easily accessible, major convention center. Sapporo Convention Center completed construction at the end of 2002 and opened for use this past June. The new convention center is just a six-minute subway ride from downtown Sapporo to Higashi Sapporo Station, plus an easy 10-minute walk from Higashi Sapporo Station.

<< Overview of Sapporo Convention Center >>

Sapporo Convention Center's facilities include:

The center is a full-service facility, capable of handling both large-scale and small conferences, as well as their breakout or satellite sessions, and the full range of exhibitions and hi-tech demonstrations that convention planners may wish to make available to attendees. The center's built-in equipment includes the full complement of AV and lighting systems, the ability to transmit live conference broadcasts, and high-speed, advanced digital connectivity, including Internet connections, making this convention center a structure ready to meet the expectations of the Information Technology age.

<< The Center's Site and Spacious Layout >>

The convention center occupies part of an expansive site that was previously used by Japan's National Railroad as a freight yard. The center's design took full advantage of the large site by locating each of the Main Hall, the Conference Hall and the meeting rooms, Mid-size Hall and Small Hall in three separate, freestanding buildings. All three buildings' entrances face onto a central, garden courtyard, connecting the structures into a single, spacious campus.

<< The Project Team >>

For the convention center's architectural design, four design firms: Hokkaido Nikken Sekkei; Nihon Sekkei; Sun Sekkei; and, Sapporo Nissoken combined efforts in a working arrangement created specifically for this project. The joint venture of Taiyo, Kankyo, Tsukada and Maki corporations was responsible for the mechanical and electrical engineering design.

For the general contracting work, the project was divided into two sections awarded to two different consortiums. General contracting responsibilities for the buildings of the Main Hall and the Conference Hall were awarded to a consortium of Obayashi, Tanaka, Mitsui and Satoh corporations and the other building had a consortium of Chizaki, Maruhiko-Watanabe and Kishida corporations. Nagata Acoustics served as Acoustical Consultant on all aspects and both sections of the project, with responsibility for the acoustical designs and construction management of acoustical aspects of the projects, as well as post-construction measuring and analysis.

<< Features and Uses of the Main Hall >>

Main Hall
(©Hokkaido Nikken Sekkei)
With area dimensions of 40 m. (131 ft) wide x 60 m. (197 ft) deep, and a 12 m. (39 ft)-high ceiling, the convention center's main hall doubles as both a conference hall and an exhibition hall. It features a stage that can be raised and lowered to blend with the auditorium's flat floor, a retractable proscenium and suspended stage batons, as well as movable audience seating for 1,000 persons, and accommodates as many as 2,500 persons when configured for exhibitions.

Through the use of 12 m. (39 ft)-tall, oversized movable partitions, the main hall can also be divided into two or three halls of smaller size. Above the locations in the hall where the partitions will be deployed, we specified the installation of sound isolating barriers in the open space above the ceiling. The sound isolation barriers ensure effective sound isolation during simultaneous use of the separate spaces created by the partitions.

<< The Main Hall's Sound-absorbing Interior Acoustical Design >>

Aluminum panels are the primary material used for the Main Hall's interior walls, rising to second-story height. Between the top of the aluminum panels and the ceiling, the walls are exposed concrete. Some of the aluminum panels installed on the side walls are perforated and backed with glass wool having sound absorbing properties. In order to prevent echoes, we specified the placement of the side-wall panels so that each perforated panel on the right or left wall faces a non-perforated panel on the opposite wall.

The entire rear wall of the auditorium is also finished with sound-absorbing treatment adapted to fulfill the sound-absorbing specifications of our acoustical design. The all aluminum panels on the rear wall are perforated and backed with glass wool. The upper portions of the rear wall are covered with glass wool boards on concrete. The lower section of the rear wall opens to storage space for the hall's movable seating, so for this portion of the rear wall, we installed an acoustically transparent, aluminum sliding wall with a ribbed surface, and utilized the sound absorbing properties of the stored seating to create a sound-absorbing surface.

We also incorporated sound-absorbing elements into the main hall's ceiling design by creating a pattern of 600 mm. (24")-wide stripes made of perforated paneling backed by glass wool. In addition, to ensure that the reverberation times would not be overly long when the hall is partitioned into smaller rooms, we used the same sound absorbing methods on the partitions as on the hall's fixed walls.

When the main hall is unoccupied (with or without the movable seating deployed), at 500 Hz, the hall's reverberation time is 2.3 seconds with an entirely flat floor. When the stage is raised and the seating is deployed, the reverberation time is 1.8 seconds (at 500 Hz, with the hall unoccupied), and when the hall is divided into thirds, the reverberation times range from 1.8 to 2.2 seconds.

<< The Main Hall's Sound System >>

We installed three kinds of loudspeakers in the Main Hall to meet the hall's several configurations and intended uses. One set of loudspeakers is a suspended (retractable) main cluster of six units (three facing left, center and right towards the front half of the hall and three facing left, center and right to the rear half of the hall) for use when the entire hall is configured with its stage and audience seating. Additionally, we placed embedded sub-speakers in the side wall for use when the hall is partitioned and 54 ceiling speakers (18 in each for each third of the hall that can be segregated by partitions) for PA announcements and background music when the entire hall is configured as a flat-floor auditorium (with the stage lowered to flat-floor level), and to be used as auxiliary loudspeakers with the main cluster and/or sub-speakers.

To handle adjusting the equalization and the delay of the sound system's total of 33 channels, we selected a DSP (digital signal processor) that has settings fully controllable from a PC in the hall, and we installed two of these DSPs with a cascade connection between them. One advantage of this system is that it simplifies the sound system by eliminating the need for separate, dedicated pieces of equipment to perform different sound system control functions. Another advantage is that controlling the settings for the sound system's many channels is centralized in a single PC.

<< Sound Isolation and Noise Control >>

Because the Main Hall occupies its own, free-standing structure, we relied on the building's structural separation and sound-isolating doors to provide the Main Hall's sound isolation from the convention center's other key facilities. For the sound isolation between the Main Hall and the Conference Hall, we achieved effective sound isolation performance for at least 85 dB, at 500 Hz. Between the Main Hall and the Mid-size and Small halls, we achieved effective sound isolation performance for at least 83 dB. (Both of these measurements are based on the sound source being the Main Hall.) We controlled HVAC system noise to under NC-25.

<< The 700-seat Conference Hall >>

Conference Hall
(©Hokkaido Nikken Sekkei)
The convention center's fully equipped Conference Hall boasts six simultaneous translation booths, seats 700, and includes a fixed-seating balcony along its rear wall, appropriate for observers or as a press gallery. The Conference Hall's dimensions are 20 m. (66 ft) wide x 30 m. (98 ft) deep, with a ceiling height of 11 m. (36 ft).

The Conference Hall has wall-to-wall carpeting. The walls of the hall's ground-floor level are finished using a local stone named "Sapporo Nanseki," the balcony level walls have wood louvers and the ceiling has aluminum louvers. An inverted-dome-shaped, elliptical-motif fixture covers a large portion of the ceiling's center, from which hangs a chandelier of inspirational design that evokes the image of Hokkaido snow falling from the sky.

For the hall's ground floor, stone walls, we specified an openwork design and installed glass wool and glass cloth behind the stone openwork to create a sound-absorbing surface. In addition, we specified the use of some cleft stone pieces intermingled with the mostly smooth-finished stone, so that the uneven surfaces of the cleft stone would prevent flutter echoes.

The upper walls' wood louvers have an alternating pattern of two kinds of vertical ribs. The surfaces of one kind of rib curve gently, like archery bows, towards the hall interior and measure 45 mm. (2 in.) wide x 100-200 mm. (4 - 8 in.) deep. These ribs alternate with straight ribs measuring 100 mm. (4 in.) wide x 90 mm. (3.5 in.) deep. The purpose of alternating two kinds of ribs is to inhibit the negative acoustical impacts that can be produced by wall surfaces with uniform ribbing. Behind the louvers, we installed a sound absorbing infrastructure of perforated panels and glass wool. The Conference Hall's reverberation time measures 1.2 seconds, at 500 Hz, with the hall unoccupied.

The Conference Hall's sound system uses the main loudspeakers that locating at both sides of the three-sided multi-screen at the front of the hall, and these loudspeakers are supported by additional loudspeakers in the ceiling.

The HVAC system noise level is controlled to below NC-25.

<< Summary of the Center's Other Facilities >>

In addition to the Main Hall and the Conference Hall, the new center's facilities include the pantry-equipped, 600-person-capacity Mid-size Hall, making it usable for receptions where food is served, and the 191-seat Small Hall, which has stepped, fixed seating. To maximize the flexibility of the center's 15 meeting rooms, they are equipped with partitions so that their sizes can be adjusted to the size requirements of many different gatherings.

The convention center's website (http://www.sora-scc.jp/) lists a long and diverse schedule of professional, academic and other conventions, conferences and exhibitions already signed up to make use of this new, full-service convention center. I hope that this excellent start will be matched by a vibrant future for the center in the heart of one of Japan's best-known northern cities.

Sapporo Convention Bureau (Sapporo International Communication Plaza (a non-profit foundation)) can be reached by phone at +81-11-211-3675.

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Nagata Acoustics News 03-07 (No.187)
Issued : July 25, 2003

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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