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

Nagata Acoustics News 04-11 (No.203)
Issued : November 25, 2004

Matsumoto Performing Arts Centre Opens

Overview of the Centre's Halls and Rehearsal Spaces

by Ayako Hakozaki

Matsumoto Performing Arts Centre ("MPAC") is located an easy 800 m. (0.5 mile) walk east of Nagano Prefecture's Matsumoto Station, on the site of the old Municipal Community Center. MPAC's facilities include a Main Hall, Small Hall, and large and medium-size rehearsal rooms. On August 29, 2004, the Centre celebrated its opening with the Saito Kinen Festival performance of Alban Berg's opera "Wozzeck" in the Main Hall, and a performance of Moliere's "Scapin" in the Small Hall. Mr. Kazuyoshi Kushida, MPAC's General Manager and Artistic Director, directed the inaugural's Japanese rendition of "Scapin," and also starred in the leading role. Mr. Hiroshi Watanabe, well known in Japan as the former Chief Manager for Cultural Events at Tokyu Bunka Mura in Tokyo, became Producer and Executive Director.

<< MPAC's Effective Use of Limited Space>>

Plan (Level 3)
Visitors to MPAC enter the building from the main entrance on the north side of the site and are immediately welcomed by soft light that filters through sections of glass embedded in the GRC (glassfibre reinforced concrete) panels of the entranceway's west wall. A wide stairway leads upstairs from the entrance to the third floor lobby. This lobby connects the foyers of both the Main Hall and the Small Hall and is an area of spacious dimensions that makes it possible to forget the very narrow shape of the land on which the Centre was constructed.

Standing at the top of the lobby's stairway, the visitor's eye is immediately drawn to the glass wall that separates the lobby from the Main Hall's stage control room. Through this glass wall can be seen not only the control room and the hall's stage beyond it, but also a view clear across the hall's audience seating area to the rear of the hall.

On the building's fifth floor, directly above the rear stage of the Main Hall and the lobby, are found the Centre's large and medium-size rehearsal rooms. Architects Toyo Ito & Associates designed the Centre and a consortium of Takenaka, Toda and Matsumoto Doken corporations built the facility.

<< The Main Hall >>

Main Hall
The Main Hall has four balcony tiers and its horizontal plane has a horseshoe shape. Maximum occupancy is 1,800. Upon entering the hall, the impressive use of color in the hall's interior creates an eye-catching sensation. The hall's walls and audience seating upholstery near the stage are uniformly black, but as one moves away from the stage, the color of the walls and seating upholstery changes gradually through numerous shades of pink, completing the gradation with a pale rosy tint at the rear of the auditorium. In addition, the off-white color of the ceilings above the balcony tiers and the strings of lighting along each balcony combine with the pink gradation to create a posh and glamorous setting that naturally enhances the audience experience.

The Main Hall is designed as a multipurpose hall with a stage that can be temporarily customized to match the needs of dramatic performances, opera and music concerts. Depending on the performance genre, the hall's functionality, maximum seating capacity and hall reverberation time can be customized by changing the height of the ceiling and/or the height of overhead acoustical reflection panels, opening the orchestra pit or closing it to create an apron stage and by using the stage's portal bridge to set up an on-stage acoustical shell.

The Main Hall ceiling can be lowered to reduce the hall's height by two balcony tiers, for a decrease in hall spatial volume of 4,500 cu. m. (26,000 cu. ft). The Centre uses the label "large hall" for the Main Hall's configuration with full spatial volume and the label "mid-size hall" when the hall's configuration has the ceiling at its lowest possible height. In addition, the hall stores stepped, removable seating that can be deployed at the rear of the stage to create an experimental theater space.

<< The Main Hall's Acoustics >>

Our acoustical design of the Main Hall included a focus on preventing two undesirable tendencies that commonly occur in horseshoe configuration halls. One concern was the difficulty of obtaining early reflections at the center of the audience seating area. The second concern was that reflections off the curved rear wall of the stage might produce echoes.

We first addressed these concerns during the design stage, using computer simulations to develop and validate our design approach. Thereafter, during the construction phase of the project, we continued our evaluation and testing in a 1/20 model.

Our resulting successful design implements a wave-shaped wall at the front sections of the auditorium's side walls and precisely angled ceiling panels as part of the ceiling's "gallery" of lighting apparatus. These design elements effectively deliver early sound reflections throughout the hall's seating area, including the seating at the center of the hall.

To prevent echoes, we adopted wave-shaped designs for both the balconies' handrails and the rear wall of the auditorium. In addition, we added delicate wave patterns to the surfaces of the acoustical panels at the front parts of the auditorium's side walls, as well as to the surfaces of overhead acoustical reflection panels and the ceiling spot gallery that can be raised and lowered. The hall's reverberation time, when configured for concert use and with full occupancy measures 1.4 seconds.

<< The Small Hall >>

Small Hall
The Small Hall is a box-shaped room designed primarily for theater performances. Acoustical curtains can be deployed at the side walls of the stage and from the upper portions of the hall's side walls to adjust the hall's reverberation characteristic. The Small Hall has a skylight installed in the roof above the stage, providing an extra light source that is particularly useful during stage set-up activities. To insulate the hall from exterior noise that might enter the hall through the skylight, we added a soundproofing panel that can be slid into place over the skylight to shut out noise from outside the building.

<< The Sound Absorption and Sound Isolation for the Rehearsal Rooms >>

In the large and mid-size rehearsal rooms, we hung HVAC ducts made of fiberglass from the ceiling, selecting this material so that the ducts would also act as sound absorbers and, in addition, prevent flutter echoes. We also partially covered the rehearsal rooms' walls with sound-absorbing, perforated aluminum panels, distributing these sound-absorbing surfaces across the walls.

Our acoustical design included requirements for effective sound isolation between the two rehearsal rooms and the Main Hall and also between the two rehearsal rooms. To meet these requirements, we adopted anti-vibration and sound isolating structural designs for each of the rehearsal rooms.

One wall of the large rehearsal room is made entirely of glass panels and faces onto the Centre's rooftop garden. The glass panels can be fully opened to create a refreshing space seamlessly connected to the outdoor garden. The large rehearsal room will be used for an actor's training school and other workshops as well as for rehearsals.

MPAC's Stage Sound Systems

by Makoto Ino

Reversible Stage
In the development of stage sound system designs for the Centre's halls, we worked closely with Mr. Kunihiko Ichiki (of Setagaya Public Theatre), who provided theater consulting expertise as our advisor on this part of the project. Yamaha Sound Technologies, Inc. installed the stage sound systems in the halls.

The functionality and quality of the stage sound systems of both the Main and Small halls exceed the typical specification standards set for multipurpose halls. In particular, the halls' sound systems boast robust sound effects editing and reproduction capabilities and an impressive in-house production-communication system.

In addition, because the Main Hall has a "second personality" as an experimental theater space when the 360-seat-capacity stepped, removable seating system is deployed at the rear of the stage, turning the rear of the stage into the front of the experimental theater space, our stage sound system design needed to prioritize the use of portable equipment and placement flexibility. We specified a complete system of free-standing, movable sound system equipment intended for shared use in the rehearsal rooms as well as in both halls.

<< The Main Hall's Loudspeaker System >>

The Main Hall's main loudspeakers are a 3-way system that combines a 2-way, one-box loudspeaker and a subwoofer. We installed these loudspeakers at left, center and right positions along the stage proscenium and at the right and left sides of the stage. To prevent the phenomenon of cloudy sound and reduced sound clarity that sometimes occurs with enclosed spaces for loudspeakers, I customized those spaces by making the interiors of their casings sound absorbing, a technique I used before on earlier projects.

Additionally, on this project, I discovered another beneficial way to modify the loudspeakersf spaces at the stage sides. In order to improve the passage of sound out of the loudspeakers, I decided to use black stage curtain cloth instead of the usual rigid board material for the rear panel of the loudspeakers' spaces. I came upon the idea for this innovation serendipitously while working on the job site, and found that the cloth backing resulted in clearer sound generation for low-register tones than I obtained with the board material. Quite amazingly, the use of the stage curtain cloth for the rear side of the loudspeakersf enclosing spaces also reduced a surround sound phenomenon that had been occurring in the central area of the stage before I implemented this modification. As would be expected, with this modification, I had no trouble performing corrective adjustments to the sound quality and the resulting amplified sound has not only excellent clarity, but also warmth and richness.

For the reproduction of sound effects, we installed multiple large loudspeakers across the ceiling and in the side walls of the auditorium. For the hall's mixing console, we selected a top-of-the-line digital console model with the most extensive assortment of available features.

<< A Focus on Flexible Use for the Small Hall's Sound System >>

Compared with the Main Hall's high-end mixing console, for the Small Hall, where we anticipate a wide variety of recitals, dramatic theater and other genre performances, we selected a small and portable digital mixer and free-standing, portable loudspeakers, prioritizing flexible and easy configuration changes as key objectives of this hall's sound system design. In selecting the loudspeaker and power amplifier models, we focused on ease of use and the ability to relocate the equipment from room-to-room within Matsumoto Performing Arts Centre. We chose German manufacturer d&b's products for almost all of the Small Hall's sound system equipment.

The d&b power amps we selected contain internal filters for the sound quality correction of each loudspeaker, plus remote power on/off, mute, sound volume setting and monitoring, and error monitoring capabilities from an ordinary laptop or desktop computer. Because these functionalities enable effortless daily maintenance and monitoring of the sound system equipment, our product selection supports MPAC's implementation of effective operations activities in addition to providing a flexible system that can be configured to meet many diverse performance needs.

<< High-end Systems for Professional and Frequent Utilization >>

At MPAC, the programming plans call for opera and theatrical drama to be performed regularly in the Centre's two halls. In addition to hosting one-or-two-night performances of traveling productions, the Centre will plan and produce professional productions that will be performed with running engagements extending across periods of weeks or months. These plans for professional use and a high utilization rate of the halls influenced the architectural design of the two stages and decisions regarding the stages' scopes and specifications.

The anticipated professional quality of the productions and high utilization rate were also among the important factors considered when we selected the stage sound system equipment. Our approach was to maximize the functionality and performance specifications of the stages' architectures and sound systems to match the anticipated needs of opera and theater professionals who we expect will use the stages and their sounds systems on a regular basis.

<< The Value of a Robust In-house Communication System >>

One set of equipment essential to professional-quality performances is a robust production communication system. There are many electronic devices made for theaters' production communication systems, including audio-visual monitors, call staff and performer systems for easy communications with dressing rooms, other back-stage areas and other parts of the halls, talkback system for theater production set-ups and tear-downs, intercom systems and cue lights.

The installation of an effective production communication system ensures that directors' and designers' instructions can be conveyed anywhere in the hall and to anyone in the hall at the precise time the communication needs to occur. Equipment can be adjusted and operated to carry out the artistic intent of the director or set designer, and the increased communication capabilities also increase the safety level of production preparations and performances.

Since the end of the 1980s, Nagata Acoustics has worked to design in-house production communication systems that bring together devices with the best combinations of functionality, improved ease of use and least cost. It is only recently that devices with the appropriate quality, user-friendliness and price tags have become available for the effective implementation of small-scale systems in public, multipurpose facilities such as MPAC. The system we installed at MPAC provides a full complement of features, including specifications that a few years ago would have been considered expensive optional add-ons. For all who may have the opportunity to do so, I would urge a visit to MPAC's backstage area to see the robust in-house production communication system we installed there.

<< The Stage Design Team >>

In designing the stage sound systems and in-house production communication systems, we joined with a team of theater experts who designed other aspects of the halls' stage designs. Mr. Motoi Hattori of Akari-gumi designed the lighting. Mr. Tetsuya Oguri, of Art Creation, served as an advisor on the stage machinery and Prof. Shozo Motosugi of Japan University's College of Science and Technology Architecture Department, oversaw the overall aspects of the theater and stage design work at the program level. Matsumura electric mfg installed the stage lighting and Kayaba System Machinery installed the stage machinery.

The URL for MPAC's web-site (in Japanese only) is http://www.city.matsumoto.nagano.jp/mpac/.

Nagata Acoustics Celebrates 30th Anniversary

by Satoru Ikeda

To celebrate the 30th year of our establishment, Nagata Acoustics thanked those who have been working with us, some of the clients and the arts community for their years of support with an Appreciation Concert performed at Toppan Hall on October 28, 2004. The concert featured harpist Naoko Yoshino in a program that included both music performance and some words from Ms. Yoshino in honor of the occasion.

Ms. Yoshino told the audience, "When I play music, my main wish is that what the audience hears matches as closely as possible, in a positive sense, the sounds I aim to convey." She also said, "Toppan Hall is one of the best halls for solo harp performance. It has an appropriate amount of reverberation and fine tones do not get buried in the reverberation. The subtle and delicate nuances I want to express in my music can be heard by the audience just as I created them, without any adulteration."

Ms. Yoshino treated the audience to a varied program of harp compositions, from Baroque period works to adaptations of familiar piano tunes. The event deftly presented the delicate and subtle tones of the harp instrument and the suitability of the venue to this music.

This concert provided an excellent example of how "a hall is like a musical instrument and as important as the musical instruments to the audience's listening experience." Ms.Yoshino made this clear in her remarks and her performance that gave us a great encouragement.

Nagata Acoustics donated a portion of the gift given to us to relief organizations helping victims of the recent Niigata Chuetsu earthquake and the typhoon in Hyogo Prefecture.

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Nagata Acoustics News 04-11 (No.203)
Issued : November 25, 2004

Nagata Acoustics Inc.
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Hongo, Bunkyo-ku, Tokyo 113-0033 Japan
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