Quietness, Comfortable Sound and Excellent Acoustics NAGATA ACOUSTICS

News 10-06 (No.270)

Issued : June 25, 2010

[ Japanese Version ]

Ueno Gakuen University's Ishibashi Memorial Hall, the Legacy and the New Hall

By Dr. Minoru Nagata, Founder of Nagata Acoustics

<< The History behind Ishibashi Memorial Hall >>

The Original Ishibashi Memorial Hall
The Original Ishibashi Memorial Hall
19 Nov. 2005

The New Ishibashi Memorial Hall
The New Ishibashi Memorial Hall

The new Aeolian Hall
The new Aeolian Hall

Ueno Gakuen University began as Ueno Girls' School in 1904. The school's founder, Zogoro Ishibashi, aspired to establish a school where girls and young women would learn the spirit of "self-awareness". After the end of World War II, Japan's educational system was restructured and Ueno Girls' School became two schools, Ueno Gakuen Middle School and Ueno Gakuen High School.

In 1949, Ueno Gakuen High School became the first all-girls high school in Japan to establish a music track. Thereafter, in 1958, Ueno Gakuen University established its Music Department and began offering Japanese girls and women the opportunity to pursue a music concentration at the university level. In 1974, Ishibashi Memorial Hall opened, named after the school's founder and commemorating the 70th anniversary of the school's founding.

<< The Original Ishibashi Memorial Hall's Innovative Concert Hall Design>>

The original Ishibashi Memorial Hall's 662 seats, its 36-stop, three-tier keyboard pipe organ installed front and center at the stage rear, and its rich overall acoustics and particularly splendid mid- and upper-register reverberations made this medium-scale hall the focus of attention in Tokyo from the day it opened. At the time, Tokyo had very few concert halls of this size.

Ishibashi Memorial Hall was Nagata Acoustics' first acoustical design project. Nagata Acoustics was then a fledgling company and I decided to draw a clear line of distinction between my acoustical design approach for the hall and the multipurpose hall acoustical designs prevalent in Japan at the time. I had spent a year studying in West Germany and my first-hand experience hearing the acoustics of Europe's old, stone cathedrals and study of West Germany's post-World War II research into the acoustical effects of early sound reflections informed my thinking about the acoustical design of Ishibashi Memorial Hall.

When the original Ishibashi Memorial Hall opened, its reverberation time of 1.5 seconds caused certain local classical music performers to object to the "liveliness" of the hall, but as time passed, their consternation dissipated of its own accord. However, in the 1980s, when Tokyo experienced a concert hall building boom and the addition of one after another new venue of similar size to Ishibashi Memorial Hall, these new venues overshadowed Ishibashi Memorial Hall and caused the hall to become a relatively forgotten presence of the Tokyo classical music scene.

<< Ueno Gakuen Adjusts to a Changed Tokyo and Economic Environment >>

During the same period when concert hall venues in Tokyo increased, the number of students attending Ueno Gakuen University, as well as the middle school and high school markedly decreased. In 2007, the schools decided to take the modernizing step of becoming co-ed institutions.

The schools also decided to give a major "face lift" to their campus, which is located in the Higashi Ueno section of Tokyo. On the western half of the site, they would build a 15-story building of classrooms for the university, the junior college and the high school. On the eastern half of the property, where the original Ishibashi Memorial Hall stood, they would build a 14-story office building and allot floors one through five for a new concert hall.

<< Nagata Acoustics Designs the New Ishibashi Memorial Hall >>

To our delight, the Ueno Gakuen Educational Foundation (the schools' umbrella organization) selected Nagata Acoustics as the Acoustical Consultant to design the acoustics of the new Ishibashi Memorial Hall. Moreover, the foundation expressed the strong desire that the new hall recreate the acoustic personality of the original hall, and we developed the new hall's acoustical room design with this goal in mind.

Other aspects of particular focus on this project included improving the vibration and sound isolation characteristics of the hall to isolate it from the nearby subway line and train yard. In addition, we enlarged the dimensions of the stage's floor and rearranged the locations of dressing rooms and other support rooms to make their access and use easier for performers and hall personnel.

Platform Company performed the project management role and a portion of the project's architectural design. GKK Architects and Engineers served as the lead architect and Shimizu Corporation was the general contractor. The project's construction completed in March, 2010 and Ueno Gakuen Foundation held the hall's Grand Opening in May. We dedicate most of this issue of the newsletter to the topic of the new Ishibashi Memorial Hall project.

Room Acoustical Design and Sound Isolation Design of the Project

By Ayako Hakozaki

<< Room Acoustical Design of the New Ishibashi Memorial Hall >>

As Dr. Nagata mentioned above, the new Ishibashi Memorial Hall's client required that the new hall "inherit" the acoustical personality of the original hall. As a first step toward this goal, we began the room acoustical design work by investigating and reconfirming the original hall's room physical specifications and acoustical characteristics.

The original Ishibashi Memorial Hall's ceiling, with its steeply sloped, cathedral-like angles, was the hall's most defining architectural characteristic. Using computer simulations, we confirmed that the ceiling's steep, cathedral-like angles caused reflections from sound produced on the stage to reach the audience seating in abundant quantities. Clearly, these abundant reflections figured significantly in producing the hall's well-known rich room acoustical characteristics. Additionally, the original hall had concrete sidewalls that, in the section of the audience seating closest to the stage, gradually widened outward (away from each other). The shape of these sidewalls had a design that also progressively stepped the walls outward, like the surface of a folding fan when it is stretched open. The concrete sidewalls provided effective sound reflecting surfaces for low frequency sounds and this also made a valuable contribution to realizing the hall's rich acoustics.

To recreate the original hall's acoustics in the new hall, our design reused the acutely angled, cathedral-like aspects of the original hall's ceiling. To improve the usability of the stage, we increased both its width and depth, compared with the dimensions of the original hall's stage. For the portion of the new hall's sidewalls alongside the audience seating nearest the stage, we also adopted the original hall's sidewall design, and we specified precast concrete panels as the material for the sidewalls to obtain the same rich acoustics for low frequency sounds as the original Ishibashi Memorial Hall.

Unlike a pure cathedral ceiling design, the original hall's design formed a trapezoid shape at the top, with a flat portion instead of a peak. Between the two steeply sloped ceiling surfaces, the flat portion of the ceiling extended the entire length of the hall, from the stage to the rear wall. This flat ceiling portion of the original hall sloped gently downward towards the rear of the hall. In the new hall, we changed the design of this portion of the ceiling to be of level height, thereby increasing the overall air volume in the room and obtaining a slightly longer reverberation time in the new hall. We measured the new hall's reverberation time during the new hall's April 25 pre-opening concert, when the hall had a full audience, and found that the new hall has a 1.8 second reverberation time (at 500 Hz).

<< Room Acoustical Design of Aeolian Hall >>

The new Aeolian Hall accommodates uses stackable chairs to seat an audience of up to 84 persons and, with about half the spatial room volume of the old building's Aeolian Hall, might be called a mini-size hall. The initial project plan designated this space as a rehearsal room, but Ueno Gakuen requested to continue the legacy of the original Aeolian Hall by designing the room as a space for performances before audiences. We created a room design appropriate for concerts that feature early instruments and small chamber music ensembles.

This hall's small size challenged us to find ways to place sufficient sound-diffusing elements on the walls and to sufficiently disperse sound absorbing elements. The architects spent many hours designing the right combination and placement of these elements. Eventually, we achieved a design that offers performers and audiences of early music appropriate acoustics and an unpretentious atmosphere.

<< Vibration and Sound Isolation Design >>

Because the new Ishibashi Memorial Hall and Aeolian Hall occupy the first five floors of a 14-story office building, this project's sound isolation design included ensuring sound isolation between the halls and the offices above them. Also, because the building is located both adjacent to the Ginza subway line's train yard and about 100 m. from busy Showa-dori Avenue, which has the Hibiya subway line running below it, our vibration and sound isolation design also gave high priority to isolating Ishibashi Memorial Hall from vibration produced by the trains.

We adopted an anti-vibration sound-isolating structural design for Ishibashi Memorial Hall. Our design utilized the precast concrete panels of the hall's sidewalls to implement the vibration and sound-isolating structural aspects of the acoustical design, resulting in intricate specifications and construction requirements. Both the engineers who produced the construction drawings and the field construction personnel who built the hall exerted dedication and focus to implement the design and successfully achieve the desired results. The new Ishibashi Memorial Hall's acoustics demonstrate a high level of sound isolation performance. The subway noise that caused negative comments about the old Ishibashi Memorial Hall is gone and replaced by a quiet hall environment.

"The Sound System Design"

By Masaya Uchida

The new Ishibashi Memorial Hall, seen from one side of the hall
The new Ishibashi Memorial Hall
seen from one side of the hall

The new Aeolian Hall stage
The new Aeolian Hall stage

Ishibashi Memorial Hall set up for a Noh performance
Ishibashi Memorial Hall
set up for a Noh performance

To plan the sound system design of the new Ishibashi Memorial Hall, I began by meeting with Mr. Orihara, who has been in charge of the hall's sound system operation since the opening of the original Ishibashi Memorial Hall in 1974. Based on Mr. Orihara's input and opinions, I devised a sound system for the new hall that provides ample sound recording functionality and natural, clear sound amplification.

In the new hall we installed a triple-point hanging microphone that can be extended down into the stage area so that sound can be captured close to its source. To capture the hall's sound reverberations in recordings, we also placed hanging microphones from the ceiling at the rear of the audience seating area.

In addition, we designed the hall so that temporary sound recording setups by external organizations can be done efficiently and robustly. Specifically, we installed electrical outlets for microphones in numerous locations of the hall ceiling, together with small openings in the ceiling that can accommodate the temporary addition of additional hanging microphones. Also, we laid sound system cable, electrical lines and cable junction boxes throughout the backstage area and at the sides of the stage, so that external organizations and professionals who will record in the hall can easily install all of their desired temporary audio equipment.

For the recording mixer, we reused the same Studer-brand mixer used in the original Ishibashi Memorial Hall.

For sound amplification, we installed line array loudspeakers and, by focusing the sound toward the audience seating area, we avoided the possibility of excessive reverberation and ensured clarity of the amplified sound. With their slim silhouettes, the line array speakers can barely be distinguished in the photo of the side view of the new Ishibashi Memorial Hall. They are the objects that appear as vertical dark lines at the wall near the edge of the stage and at the end of the side balcony. Measuring just 5 cm. wide and 6 cm. deep, we were glad to be able to choose these extremely slim line array speakers, because they have both the right functionality and they blend well with the architectural design of the hall.

In Aeolian Hall, we installed a manually-operated dual-point, hanging microphone and a microphone to capture the hall's sound reverberations. For the hall's sound amplification loudspeaker system, we adopted the same slim design speakers that we installed in the new Ishibashi Memorial Hall.

<< Stage Lighting and Apparatus Design >>

As part of its consulting work for this project, Nagata Acoustics provided the stage lighting and apparatus design as well as the room acoustical design, sound isolation design and sound system design. The stage lighting design in the new Ishibashi Memorial Hall follows the design of the original hall, with 4 lighting batons above the stage, additional lights at the sides of the front of the stage and ceiling spotlights. Because of the ceiling's limited flat area, we left the lighting batons exposed to view and we focused our design efforts on the two criteria of determining the baton placements that would allow the use of the longest length batons, and ensuring that the batons would not affect the site lines from the audience seating to the pipe organ at the rear of the stage.

The Ueno Gakuen schools have a significant collection of early instruments and the schools encourage these valuable instruments' use in performances. Temperature changes can affect early instruments more than other instruments, so we took the precaution of installing heat shield filters with the ceiling spotlights in order to regulate the temperature on stage.

We also installed a unique stage apparatus that has its origins in the original Ishibashi Memorial Hall. This is a curtain suspended from a baton with the purpose of hiding the pipe organ. The hall uses this curtain during its annual Noh performances. For this unusual apparatus, we used the lighting baton closest to the rear of the stage (and closest to the pipe organ) and we supplied support bars that attach to fittings at the end of the baton and enable the baton to be turned so that the curtain can be unfurled and rolled up.

In Aeolian Hall, we installed 9 spotlights that have automatic controls for raising and lowering them. We also added heat shield filters to these spotlights.

<< The New Ishibashi Memorial Hall-Continuing a Legacy and More >>

By Dr. Minoru Nagata

I listened to the new Ishibashi Memorial Hall during pre-opening test performances, and again during three grand opening performances, one of which was a Noh play. Consistently, the new hall adheres to the aspects of the original hall's acoustics that both the Ueno Gakuen and we dearly wanted to preserve. At the same time, the new hall presents the image of a more sophisticated interior space that responds well to Ueno Gakuen's need for both pomp and subtlety. I hope that the new hall will become the mainstay of the school's performing arts activities and that Ishibashi Memorial Hall will bring a fresh new spirit into Tokyo's music world.

Bamberg, Germany Concert Hall Renovation

By Yasuhisa Toyota

Renovation - Before
Renovation - Before

Renovation - After
Renovation - After

The town of Bamberg resides in Germany's southern state of Bavaria and is a small city of some 70,000 people. The town escaped the ravages of World War II, enabling its streets to still have an appearance that harks back as far as the middle ages. In 1993, UNESCO named Bamberg a world heritage centre in recognition of both its beauty and its historical significance.

The town of Bamberg is also home to the Bamberg Symphony Orchestra (Bamberg Symphoniker), Bavaria's state sponsored orchestra (Bayerische Staatsphilharmonie). The orchestra has a comparatively young history, having been founded in 1945 by musicians of German descent who were forcibly repatriated from Czechoslovakia to Germany after the end of the war.

Bamberg Symphony Orchestra enjoys an internationally acclaimed reputation, both for its recordings and its tours on many continents. At home, of the total population of 70,000 people in Bamberg, fully 6,000 residents subscribe to the orchestra's subscription concerts, an incredible percentage. When I think about what such a percentage of concertgoers would mean in a large metropolis like Tokyo, I realize that Tokyo would need to have one million season concertgoers to have a similar ratio of concertgoers to population.

Bamberg Symphony Orchestra Stage Layout
Bamberg Symphony Orchestra Stage Layout

Clearly, the town of Bamberg supports its orchestra enthusiastically. Nevertheless, even with nearly 10% of the population attending subscription concerts, 6,000 people are not sufficient numbers to sustain a 21st century professional orchestra. Rather, the orchestra distinguishes itself by performing on the world stage, both through its large discography and its frequent worldwide tours. Japan counts as one of the orchestra's repeat tour destinations, and some Japanese classical music fans have become so accustomed to attending Bamberg Symphony Orchestra concerts that they consider it a given that the orchestra will be in town regularly. In this way, the name of the small town of Bamberg has become well-known throughout the world of classical music through the accomplishments and acclaim of its symphony orchestra.

<< The Orchestra's Main Hall, the Joseph-Keilberth-Saal >>

A concert hall for the Bamberg Symphony Orchestra opened in the town of Bamberg in 1993. Named after the orchestra's first conductor, Maestro Joseph Keilberth, the concert hall has a modern design, but soon after its opening, several problems became apparent. In particular, the performers on stage could not hear themselves or their fellow musicians.

In early 2005, renovation plans began for the concert hall and Nagata Acoustics was selected for the role of acoustical consultant. During the next three years, we interviewed and met with the orchestra's conductor and members of the orchestra to understand their opinions and requirements, and we formulated the renovation plan.

<< The Renovation Plan >>

For the first phase of the project, during the hall's 2008 summer recess, we focused on renovating the stage area. Specifically, we reconsidered the seating arrangement of the orchestra sections and we introduced risers of varying heights for all of the orchestra sections, including the string sections. The stepped risers, which we designed so that the orchestra's configuration on stage has a more semicircular shape, give the orchestra a more three-dimensional presence on stage and also bring the musicians physically closer to each other. As a result of these changes, the orchestra reported to us that both the conductor and the members of the orchestra can now hear each other and themselves.

In the summer of 2009, additional renovations gave the hall a "face lift". The changes included reupholstering the audience seats, painting the Joseph-Keilberth-Saal ceiling a different color and making architectural changes to enlarge the lobby and entrance. When the classical music season of autumn, 2009, began, the orchestra greeted its loyal local concertgoers to a now very visibly renovated hall.

In the future, the orchestra plans the more long-term and substantial renovations of redesigning the shape of the ceiling and the sidewalls.

Two web pages about the orchestra and this project may be of interest to the reader: the home page of the orchestra and a page about this project

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 ]