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

Nagata Acoustics News 05-12 (No.216)
Issued : December 25, 2005

Hyogo Performing Arts Center Opens

by Akira Ono

In October 2005, the Hyogo Performing Arts Center celebrated its long-awaited opening at the south entrance of the Hankyu Railway's Nishinomiya Kitaguchi Station, the site chosen for the center 17 years ago and 3 years before the Great Hanshin-Awaji Earthquake (magnitude 7.3) devastated the area. Initial selection of the architect dates back to 1992, when the government of Hyogo Prefecture awarded the project to Nikken Sekkei, based on this architectural design firm's winning proposal. In the same year, Nagata Acoustics joined the project as Acoustical Consultant, with overall responsibility for the project's acoustical design, related construction oversight, fine tuning and post-completion evaluations.

<< The Project's Survival through Earthquake and Economic Change >>

Exterior of Hyogo Performing Arts Center
As initially conceived, the Hyogo Performing Arts Center was to be one part of a major multi-structure undertaking by three entities: Hankyu Corporation, superstore Nichii Co., Ltd. (now Mycal Corporation) and Hyogo Prefecture. The January 17, 1995, Great Hanshin-Awaji Earthquake brought the project's progress to a sudden halt and precipitated radical changes to the project's deliverables. In the days immediately following the quake, many of the people associated with the project surely thought that the project might be not only stalled, but canceled forever.

Local residents, local performing arts groups and cultural organizations continued to advance the project's resumption. They recognized that the arts and culture can serve as catalysts that bring encouragement and courage to the community and help people focus on reviving and recreating lifestyles that were uprooted and torn asunder by the earthquake. The Hyogo Performing Arts Center project came to represent the rebuilding of the symbolic heart of the region's cultural life and, in 1997, the project received the "green light" to move forward.

More hurdles remained to be overcome before the groundbreaking of construction in 2002. Hankyu Corporation decided not to build a hotel, Mycal filed for bankruptcy in 2001 (completing a restructuring in 2003) and the land on which the Hyogo Performing Arts Center would be built underwent investigation to ensure no important architectural artifacts would lie forever buried beneath the project. Each of these vicissitudes stalled the project and/or resulted in substantial design changes. Both individual and organization stakeholders and participants met the project's many twists and turns with perseverance and endurance, finally culminating in the joyous grand opening of the center in October of this year.

<< The Center's 3 Halls, and Design and Construction Highlights >>

The Hyogo Performing Arts Center features three halls as its core facilities: the 2,000-seat Grand Hall classical music concert hall, the 800-seat Theater for dramatic performances and the 400-seat Recital Hall. In addition, the center has large and small rehearsal rooms, practice rooms and support rooms.

Interior of Grand Hall
The client's definition of Grand Hall included both the requirement that the hall be a world-class classical music concert hall and the requirement that it also be a suitable venue for opera and ballet performances. Specifically, our acoustical design included both narrowing the width of the audience seating area to rely on the angle of the sidewalls and the hall's eaves to deliver early sound reflections to the audience, while also taking into consideration the need to keep the audience seating at as close a distance as possible to the stage to create optimal viewing conditions for opera and ballet performances. We found the best balance of these somewhat competing requirements by building computer simulations and 3-dimensional models of the hall and examining the merits of each acoustical design option. Because the project's delays extended the time available to us to consider and refine Grand Hall's configuration, we had ample time to consider and revise the hall's shape, giving us a high level of confidence that the finalized design most closely matches the client's requirements.

The 800-seat Theater is intended as a specialty hall for drama performances. The interior walls and ceiling finishes use Japanese cedar paneling darkly stained to imbue this medium-size hall with a weighty, dignified ambience.

Interior of Recital Hall
For the Recital Hall, we adopted an arena-style configuration with a centrally-located stage surrounded by blocks of audience seating on all sides. The Recital Hall footprint is a regular octagon, and the use of this shape as the basis of the hall's design necessitated that our acoustical design proactively prevent the undesirable acoustical phenomena such as focusing that are likely to occur in halls of this shape. We angled the sidewalls gradually, from floor to ceiling, toward the center of the room, and we designed the major upper portions of the sidewalls with alternating concave and convex curves, creating a surface that looks as if the walls surround the room like an undulating wave. In addition, we deliberately located the center of the floor's regular octagon and the center of the circular ceiling to not vertically align, producing a unique 3-dimensional shape.

While I can explain the Recital Hall's 3-dimensional shape in words with comparatively little effort, building the hall to these unusual specifications posed a difficult challenge. Before the start of construction of the hall's interior, we used the 1/10 model of the hall to confirm and finalize the torsion of the ribs as they rise from floor to ceiling on the curved sidewalls' surface, and we took the additional step of building a one-half-size mockup of the sidewalls to further confirm that our specifications for the flow of the curved wall surfaces and the ribs' torsion would all fit together correctly. The Recital Hall began as a standard shoebox-configuration hall in the Hyogo Performing Arts Center's original plans and evolved during our continuous work during the long pre-construction duration into a uniquely shaped hall sharing little in common with any other hall in Japan.

<< Artistic Director Yutaka Sado's Requirements >>

From the initial stages of the project's conceptual programming, Hyogo Prefecture articulated the guiding principle that the center's highest priority be its performances. As early as 1991, the prefecture sought out and retained noted Japanese playwright Masakazu Yamazaki as the center's Artistic Advisor. Mr. Yamazaki heads the theatrical company Hyogo Performing Arts ("Hyogo Butai Geijutsu") and, with the opening of the center, he will concentrate his advisory activities on content planning and direction for the center's 800-seat Theater. In 2002, Hyogo Prefecture appointed Maestro Yutaka Sado to the position of Artistic Director, and Maestro Sado joined the project as a key stakeholder client, providing his opinion and requirements regarding the project plans for the halls.

Immediately following the announcement of Maestro Sado's appointment as Artistic Director, we visited with him in a dressing room at Osaka Symphony Hall to brief him on the Hyogo Performing Arts Center's acoustical design plans. We arrived at the dressing room minutes after he finished the concert's dress rehearsal and while he was still wearing perspiration-soaked rehearsal attire.

Without bothering to change his clothes, Maestro Sado proceeded to listen intently as we presented our acoustical design plans. When we had completed our presentation, he opened for us his copy of the score of Beethoven's Ninth Symphony, to be performed that evening. In a manner both methodical and passionate, he walked us through the score, explicating the intent of Beethoven's composition. He pointed out the importance to the work of the contrabass and timpani low-register tones and told us to build a hall where these notes would be robustly heard.

Later, during the pre-opening concerts to fine tune the Grand Hall, Maestro Sado conducted the orchestra and again focused his attention on the robustness of low frequency sound in the hall, walking from the stage to various seats in the audience and listening to the sound of the contrabass and timpani parts of the music. While it is the hall's patrons who, over time, will ultimately judge the success of our acoustical design, for now, we are content to have received high marks of approval from Maestro Sado.

<< The Center's Resident Orchestra >>

A distinguishing feature of this Japanese performing arts center is its resident orchestra, the Hyogo Performing Arts Center Orchestra. The 48 musicians who comprise this orchestra currently represent 13 nationalities, have an average age of 27 and were each selected to join the orchestra based on auditions.

The orchestra members' contracts include housing with soundproof rooms paid by the orchestra. Each musician's tenure with the orchestra is limited to 3 years and the orchestra performs an average of 90 concerts annually. Unlike a traditional orchestra such as the Vienna Philharmonic, which aims to retain musicians for many years and have them grow their talent together with the hall, a primary goal of the Hyogo Performing Arts Center Orchestra is to serve as an educational opportunity for talented young musicians.

<< Hyogo Performing Arts Center's Sold Out Opening Concerts >>

Beginning on the evening of October 22, 2005, the Hyogo Performing Arts Center held its inaugural concerts. Maestro Sado conducted the Hyogo Performing Arts Center Orchestra and the Kobe City Philharmonic Chorus in a program of Beethoven's Ninth Symphony. Tickets for 3 repeat days of this same program sold out as soon as the tickets went on sale. Two days of additional performance were added to the initial 3 days, and the tickets for the added days also sold out immediately.

On the first night of the inaugural concert performances, Maestro Sado began the concert with Bach's Aria in G, played as a memorial to the people lost in the terrible Hanshin-Awaji Earthquake. The performance of Beethoven's Ninth Symphony followed and, at the end of the performance, the hall roared with the audience's standing ovation and shouts of "Bravo!" Three women seated next to me unfurled a banner they had brought with them, emblazoned with the words "Congratulations! This is Our Piazza." The elation of the audience exceeded anything I had ever seen before at the end of a classical music concert. After the concert, I spoke with Maestro Sado, who told me that he had envisioned the concert hall taking on the personality of a community public square and his delight that the audience also perceived this role for the concert hall.

Maestro Yutaka Sado enjoys especially strong popularity in the Kansai region of Japan, the region that includes Hyogo Prefecture and is known internationally by its cities of Osaka, Kyoto and Kobe. To the reviving community of Hyogo Prefecture has come not only the opening of its long-awaited concert hall, but also the community's favorite conductor as the hall's artistic director. It will surely be a pleasure to watch and hear this winning combination lead the community's rebirth of its musical and cultural life.

Further information about the Hyogo Performing Arts Center can be found on the Center's website at http://www.gcenter-hyogo.jp

Installed Sound Systems /
Part 1: Common Causes of Client Complaints

by Masaya Uchida

Sound systems installed in any spaces all share one fundamental functional requirement: deliver human speech to the ears of everyone present. Achieving this requirement with quality means that each amplified word must be heard clearly and the content must reach the listeners with sufficient intelligibility. If the coloration of the voice(s) of the person or people speaking and the subtle nuances of speech can also be heard by the audience, the sound system approaches perfection.

Yet, when a facility administrator or a church building committee struggles with the complaint that "people cannot catch what is being said," capturing fine nuances of human speech is a utopian level of excellence far beyond the practical goal of making the amplified speech clear to listeners. What causes this frequent problem? Below are some of the reasons that 3 different kinds of facilities encounter lack of intelligibility from their sound systems.

<< Causes of Unintelligible Amplification in Indoor Gymnasiums >>

In indoor gymnasiums and swimming pools, when the names of athletes are announced, and during speeches delivered at the opening and closing ceremonies of competitions, what is being said over the sound system can sometime be unintelligible to the audience. One cause of this problem is the long sound reverberation times of these kinds of facilities. While a facility's reverberation time may not hinder sports and normal conversation, when loudspeakers are used to amplify speech, the long reverberation time may negatively impact intelligibility. Other phenomena that cause lack of amplified speech clarity are long path echoes that bounce off the interior walls and the focusing of sound reflections propagated off dome-shaped ceilings. Recent advances in loudspeaker technologies make it more possible than before to obtain clear amplified speech in spaces with long reverberation times, but if the indoor space has an extremely long reverberation time and/or echoes, then the sound system alone cannot overcome the room's conditions and acoustical room design intervention becomes necessary.

Poor intelligibility can also be caused by the sound system equipment. The most common reason sound systems cause poor intelligibility is that the loudspeakers' specifications, number of units installed, location and/or angle of the loudspeakers are often inappropriate to the indoor space. In particular, in Japanese school gyms, loudspeakers developed specifically for use in indoor athletic facilities are hung quite high on the walls and without being positioned at a downward angle. The result is not only that the amplified sound does not directly reach the audience, but also that it reflects off the opposite sidewall and/or off the ceiling, exacerbating the sound reverberation and echoes. Japanese educators point out that at ceremonial occasions held in the school gyms, students become distracted because they cannot understand what teachers are saying over the gyms' public address systems.

Another frequent cause of poor amplified speech intelligibility is inattention to the post-construction task of acoustical fine tuning to balance the loudspeaker's output level and compensate the sound quality by equalizers for specific aspects of the room's acoustical characteristics. This task may be missing entirely from the project plan or it may be performed in a rudimentary fashion or by someone who is not well qualified. Typically, behind this cause lies the assumption that the sound system is not very important in an indoor athletic facility, an assumption that results in the inability to garner the appropriate budget for the sound system and the implementation of architectural designs and installation of sound systems without consideration for the impact design and installation have on the quality of amplified sound in the completed facility.

<< Sound System Complaints Related to Houses of Worship >>

The representatives of houses of worship often request both rich acoustical characteristics to enhance the singing of hymns and organ music and, at the same time, clarity of amplified human speech for the delivery of sermons, two sets of requirements that, from an acoustical perspective, are naturally antagonistic. In these kinds of projects, successful acoustics depend on close coordination, collaboration and validation between the architectural and sound system designs. However, the integrity of an architectural design may dictate placing the loudspeakers in locations that are acoustically inappropriate or the architect may hide the loudspeakers behind cosmetic paneling that has small apertures for the sound, negatively affecting the sound waves emitted by the loudspeakers and the quality of the amplified sound, with the result that the priest's or minister's sermons become unintelligible to the assembled congregation.

Many congregations include large numbers of older worshipers. If these congregants' hearing needs are also to be satisfied by the sound system, extra attention must be given to the sound quality.

Another frequent complaint about sound systems in houses of worship stems from setups that generate howling. The main possible causes of this problem include:

The above problems relate to the sound system equipment, their layout, and other physical aspects of the house of worship. In addition to these problems, the root cause of sound system complaints can be the users. These causes fall into two categories. One category includes problems attributed to sound systems but caused by the person speaking, who may speak in a very quiet voice or mumble. The second category of is causes that result from lack of attention to adjusting the settings of the sound system. If the sound system of a house of worship has been plugged into an electrical outlet, but neither the volume nor other settings have been adjusted to the needs of the sanctuary or size of the congregation present, then poor intelligibility can result even if the sound system is well designed.

<< Examples of Concert Hall Sound System Complaints >>

Concert hall complaints about sound systems typically arise when a hall holds lecture concerts or a similar program, and audience say that they cannot hear the person speaking from the stage. Usually, the cause of this problem is either that the hall's sound system functionality was built solely as a public address system intended for brief pre- and post-concert announcements, or the sound system equipment includes a large on-stage loudspeaker for lectures, but the hall decides not to use the loudspeaker because it is not visually appealing.

If a hall has side balconies and hall adds on-stage loudspeakers to amplify speech, but locates the loudspeakers at the sides of the stage, the sound fields of the loudspeakers may not cover the side balconies. In this situation, the speech of the person on stage will not be heard clearly by that portion of the audience.

Lastly, if the sound system operator listens only to the monitor loudspeaker in a sound room, the settings may not be adjusted optimally for audience listening in the hall. This problem results from the inexperience or lack of training of the person assigned to operate the hall's sound system.

<< What We Can Learn from Reviewing Sound System Complaints >>

The key learning from a review of common sound system complaints is that good amplification of human speech from a sound system depends as much on the room's architectural design, room acoustics, proper installation of the sound system equipment, microphone use of the person speaking, and training and skill of the person(s) operating the sound system as it does on the sound system design itself. Therefore, designing and installing a successful sound system requires close interaction and collaboration with the designers of the project's other physical elements, and also with the sound system installers and the future users of the sound system.

Another key learning comes from the fact that sound system concerns often first arise only after a facility has been designed, built and opened for use. This situation results from the lack of interest or concern in the quality of amplified sound on the part of architects, sound system installers and clients. In future articles in this series, I will outline how early and proper attention to the sound system's requirements can prevent audience dissatisfaction with the quality of amplified speech delivered by sound systems.

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Nagata Acoustics News 05-12 (No.216)
Issued : December 25, 2005

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