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

Nagata Acoustics News 02-2 (No.170)
Issued : February 25, 2002

Koyanose-za Hall Opens in Kita-kyushu City

by Toshiko Fukuchi

Koyanose-za (exterior)
Koyanose-za is a new multipurpose hall constructed as one of two major facilities comprising the Nagasaki Kaido Koyanose Memorial Pavilion recently completed in the Koyanose section of Yahata-nishi Ward, Kita-kyushu City, Fukuoka Prefecture. The hall's opening coincided with New Year's Day 2001.

<< The Historical Significance of Nagasaki Kaido >>

During Japan's Edo Period (1603-1868), the reigning Tokugawa Shogunate oversaw the construction of a network of major thoroughfares (kaido) and branch crossroads in order to enforce the policy of sankin-kotai under which the daimyo lords were required to reside in the Edo capital during alternate years. The policy effectively limited the lords' ability to develop competing power bases and allegiances. The main spokes of the network of roads were the five main "highways" named Tokaido, Nakasendo, Nikkodo, Koshudo and Oshudo.

Nagasaki Kaido figured as one of the network's branch roads, but it was special in that it was the only road that connected Japan to the outside world because it extended from the town of Kokura in Fukuoka Prefecture to the port town of Nagasaki. During the Edo Period, the government forbid overseas travel as well as visits from foreigners or foreign vessels, with the exception of Nagasaki where vessels from Europe and Asia were allowed to dock and where a tiny international community resided.

Nagasaki Kaido had 25 "stops" along its route, places where inns served wayfarers and commerce grew. Koyanose was one of six stops located in the territory of the Fukuoka daimyo and was popular with travelers and merchants as a place to spend the night. In addition to the commerce generated by foot-travelers, Koyanose's economy benefited from its proximity to Onga River. The town's docks were used for boats that traveled the river and as a vibrant location for trade and industry.

Even today, some of the buildings that flanked Koyanose's Nagasaki Kaido in the days of shoguns and daimyo remain standing, creating an uncanny sense of time warp for visitors to this section of Kita-kyushu City. A few of these houses' interiors have been restored to look as they did when they were first built and are open to the public for viewing. On weekends, tourists can be seen strolling the old streets of Koyanose, which has become an established tourist attraction of Kita-kyushu City.

One of the restored houses is the birthplace of Harube Ima, a well-known Japanese radio scriptwriter, and has been designated for historic preservation as a Tangible Cultural Property by Kita-kyushu City. The design work for this building's restoration was done by SAM Architectural Design Studio, the same architects responsible for Koyanose-za Hall.

<< Memorial Pavilion Is Built on Site of Traditional Tea Houses >>

Nagasaki Kaido Memorial Pavilion has two main areas, the multipurpose hall, Koyanose-za, and a museum (Michi-no-Kyodo Shiryokan) that exhibits artwork and crafts preserved from traditional local merchant houses and farmhouses. The pavilion's site faces onto Nagasaki Kaido at the location where a traditional "town" tea house (machi-chaya) stood during the Edo Period. Then, daimyo en route to the Edo Capital lodged in special tea houses at each highway stopping point, while the "town" tea houses provided overnight food and lodging to other travelers and members of the daimyo's entourage that the special tea houses could not accommodate.

Excavation work at the pavilion site uncovered structural remains from the tea houses that stood there during the Edo Period. Initially, the pavilion's basis of design called for the construction of a single building. However, when structural remains were found from two separate tea houses, the client decided to build Koyanose-za Hall and the museum as two separate structures.

Nagasaki Kaido makes a nearly 90-degree bend in the road about midway along the edge of the Memorial Pavilion site that flanks the road. By constructing the Koyanose-za Hall and the museum as two separate structures, and taking into consideration the change in direction of the Nagasaki Kaido road, the two buildings were designed in a complementary fashion to face each other.

<< History Meets Modernity: Controlling Noise from Trucks and Traffic >>

The land at the rear of the Memorial Pavilion's two buildings leads quickly to the banks of the Onga River. A modern road artery parallels the river on the same side as the Memorial Pavilion, linking Kita-kyushu City with neighboring Nogata City. The road is heavily traveled by trucks and other traffic and is a source of noise and vibration at the Memorial Pavilion site. Addressing this environmental element was one focus of Nagata Acoustics' work on this project.

<< A Concrete Structure Helps with Sound Isolation >>

The exterior and interior of Koyanose-za Hall are patterned after a Japanese theater called "Taisho-za" located in Koyanose many years ago. While Koyanose-za Hall is designed to function as a 21st century multipurpose hall, it retains the look of the earlier theater's traditional Japanese architecture. (Please see accompanying photo.) During the initial planning stages, there was even discussion about the possibility of building Koyanose-za Hall entirely of wood, the building material used for the earlier theater. However, with our input on the sound isolation advantages of reinforced concrete buildings over wood-framed structures, ultimately the decision was made to build the hall using steel framed reinforced concrete strusturs.

<< Koyanose-za Hall's Japanese-style Interior >>

Two levels of saziki
Koyanose-za Hall is a rectangular space with a 7 m. (23 ft)-deep stage. The main audience seating area is a flat floor that measures 11.5 m. (38 ft) wide x 12.5m (41 ft) deep. Along the two longer sides of the hall there are two levels of Japanese-style rooms, known as saziki. The first floor saziki are divided into three semi-private rooms on each side of the hall. Each of these saziki is an eight-tatami-mat room (140 sq. ft in area). Sliding, opaque-paper fusuma doors separate each room from the others and there are also fusuma between the tatami rooms and the main seating area of the hall. These doors allow great flexibility in use of the space because they can be easily removed or deployed, and opened or closed, to create multiple room layouts of greater or lesser privacy. The upper level saziki, located directly above the first level ones, have wood floors instead of tatami mats, and do not have fusuma doors.

Koyanose-za seats a maximum of 300 persons. The client's primary objective was to create a hall that would serve as a kind of civic center and be used by local residents for both concerts and many other kinds of events. Consideration was also made for the hall's use as a venue for traditional Japanese performing arts, including Noh Theater, and Koyanose-za Hall has a portable Noh stage that can be deployed specifically for this purpose.

<< Koyanose-za Hall's Sound Isolation Strategy >>

The major acoustical challenge of this project was developing a robust sound isolation strategy to counter the noise and vibration from the heavy vehicle traffic along the road paralleling the Onga River in proximity to Koyanose-za Hall. (The stage end of the hall is the side of the hall nearest the source of the noise and vibration.) Our strategy relied first on maximizing the use of concrete for the hall's walls. In addition, we designed all doors and windows with double layers and we specified the installation of sound-isolating doors and window sashes.

However, since the fittings of windows and doors to a steel frame always results in tiny gaps, and gaps are also inevitable at other places in the construction where materials are joined, a key aspect of our sound isolation strategy was on-site monitoring of the construction work while it was in progress. Wherever we found a gap, glass wool or lead sheeting was used to plug or block the gap and thereby prevent noise from seeping through to the hall. Our sound-isolation strategy happily resulted in preventing external noise from negatively impacting the acoustics of events held in the hall.

<< Koyanose-za Hall's Room Acoustical Design >>

In photographs, Koyanose-za Hall's interior appears to be paneled in wood, but the ceiling material is actually aluminum and the material used for the rear walls is metal sheeting. In this way, we combined the look and atmosphere of a traditional Japanese theater with modern building technology. The reverberation time is 1.3 seconds (at 500 Hz, unoccupied).

The hall stage does not, unfortunately, have reflected panels. On the plus side, there is no free span above the stage, so that the ceiling is relatively low. This design, combined with the minimal amount of stage curtains, remedies the acoustical minus of the stage's lack of reflection panels. I have not yet personally had an opportunity to listen to a classical music concert in the hall, but I hear that musicians who have performed in the hall say that the space is user friendly for the performing musicians.

<< The Architect's Close Ties to Koyanose >>

The project's lead architect, Mr. Yoshizaki of SAM Architectural Design Studio, maintains close ties with the residents of Koyanose. His connection with the community began with a local-opinion survey he conducted concerning neighborhood development along Nagasaki Kaido. Thereafter, he deepened his relationship with local residents by participating in local event-planning activities. Through his work as the lead architect of the Nagasaki Kaido Memorial Pavilion project, Mr. Yoshizaki's ties to Koyanose grew even stronger. Recently, he used one of the houses on Nagasaki Kaido as an exhibition space and he continues to lend his creative energies to enhance Koyanose's cultural vitality.

Koyanose-za Hall's opening marks the start of a new cultural evolution in a section of Kita-kyushu City that is already rich in historical flavor and hosts many visitors. I look forward to hearing about the performing arts that will blossom in the new hall.

For more information, please contact the Nagasaki Kaido Koyanose Memorial Pavilion directly by phone at +81-93-619-1149 or by fax at +81-93-617-4949.
The pavilion's address is Koyanose 3-16-26, Yahata-nishi Ward, Kita-kyushu City, Fukuoka Prefecture.

Renovations and Acoustical Design
Part 1: Encourage the Inclusion of Acoustical Design in Renovation Plans!

by Hideo Nakamura

During the past 20 years or so, hall and theater construction in Japan experienced an economic boom. Naturally, Nagata Acoustics focused our work on acoustical designs for new venues, many of which were halls in multi-use cultural centers. For years, virtually every issue of our News and Opinions newsletter included one article or more about the opening of one of these new facilities.

<< Renovating Facilities Built Without Regard to Acoustical Design >>

Though our renovation-related work stayed out of our News and Opinions spotlight while we wrote about our acoustical design work for new halls, throughout these decades we have, in fact, been steadily engaged in acoustical renovations of churches, athletic arenas and gymnasia, and parliamentary and other legislative chambers, as well as other kinds of spaces. Some of the renovations were commissioned because the acoustical performance levels of the locations had fallen below current expectations. In these cases, our work aimed to upgrade acoustics that were previously thought to be acceptable. But the majority of our renovation work has its origin in claims and complaints because of deficient acoustics in a new facility. Moreover, for almost all of the latter renovation projects, renovations for acoustical reasons would have been unnecessary if acoustical designs and implementation had been specifically included during the facilities' initial construction.

<< Renovating the Halls of Cultural Centers >>

Most of the halls built in Japan as part of cultural centers benefited from the input of a professional acoustician and almost none of them have required remedial acoustical renovation work. For other reasons, however, many of these facilities now face the need for renovations. The cause of this need is that the buildings are aging and require upgrades and, in particular, seismic upgrades in order to meet current codes and regulations.

The construction boom of Japan's cultural centers began in the late 1950s, more than 40 years ago. In addition to the natural wear-and-tear over the past four decades, there have been many changes in the building codes and regulations to incorporate the many technological advances that improve building safety. Surveys conducted by the Public Cultural Buildings Forum and other organizations show that the number of cultural facilities that require major renovations is now increasing rapidly. Many of these halls replaced their stage equipment and audience seating after about their first 15 years of use, but the renovations required after 40 years of use must necessarily be of a much greater order of magnitude.

<< Acoustical Design Is Important in All Renovation Projects >>

The reasons for acoustical renovations can be summarized and divided into three categories:

* The building or facility itself needs renovations due to aging.
* The client desires to upgrade the acoustical performance.
* Claims or complaints about the acoustics require redress.

While the causes and circumstances of renovations may differ from project to project, the importance of acoustical design to the success of the renovations is the same in all cases, regardless of the reason why the client embarked on the renovations.

As Japan continues to weather the long economic stagnation that followed the boom-and-bust period of the 1980s, communities are unlikely to tear down old buildings and build anew. Rather, the course of action will be to make the most of existing structures, renovating them to better meet the desires and expectations of the present day. In these economic times, there is no doubt that renovation work will be a greater piece of the total construction "pie" than it was in the past.

<< A New Series of Articles on Renovations in News and Opinions >>

In response to clients' increasing focus on renovation projects, Nagata Acoustics decided to begin a new series of articles devoted to this topic. Beginning with this article, and appearing approximately on alternate months, our acousticians will introduce specific examples of renovation projects, including, as always, challenging highlights and issues we believe will interest our readers.

In the remainder of this first article, I will offer an acoustician's perspective on each of the three categories of renovation projects.

<< Renovating a Cultural Center's Hall Because the Facility Has Aged >>

* Today's Audiences Expect Finer Acoustics
Among Japan's older cultural centers, those that were built several decades ago often face the challenge of proximity to a new specialty classical music concert hall built in the past few years. This "challenger" created a new environment that must be taken into account in the acoustical decisions for the renovation project. Distinguishing the renovated hall's acoustical objectives from the acoustics of a newer nearby hall is both important and potentially problematic. The audience for both halls now knows the rich concert hall acoustics of the newer hall. To make the renovated hall attractive to this clientele requires that the renovation project's basis for design be clear and precise. Otherwise the resulting renovations may fall short of the expectations of both performers and audience members. One example of a hall that successfully re-invented itself through renovations is Tokyo Bunka Kaikan, which retains its strong appeal after its renovations, and has not been forsaken by fans despite the numerous, fine, large and small Tokyo concert halls built in recent years.

* Renovation Plans Should Start Early, with Input from the Original Construction Management Firm and Acoustical Consultant
Cultural Center halls typically need to begin thinking about stage equipment replacement and some other renovations and upgrades after the facilities have passed their 10th anniversary. The fast pace at which the need for renovations and upgrades arrives at cultural center halls makes these kinds of facilities different than other public spaces, which may not require substantial upgrades for a much longer period of time.

Most cultural centers spend their first years engrossed in getting their operations on track. At the time a hall first opens, administrators and hall directors are typically far too busy to think about the question of future renovations and hall upgrades. Nevertheless, 10 years pass very quickly. Especially in today's tough economic climate, the process of requesting public appropriations to fund hall upgrades and renovations must be made well in advance of when the monies will be needed, since the opinions and approvals of more than one governmental agency and legislative body are likely to be required.

It is not too soon to begin a hall's long-term renovation plans at the time the hall first opens its doors. It is equally important to include the original construction management firm and the acoustical consultant in developing the hall's long-term renovation plans. These professionals know the hall intimately in all its details. Including these professionals early in the planning for a hall's future renovations means that the renovation plans will benefit from the construction and acoustical professionals' specific knowledge of the original project. Their advice and contributions are critical to developing hall renovation plans that can be executed successfully and with the desired results.

* Minor Renovations Can Impact a Hall's Acoustics
Cultural center halls are built and outfitted with a vast variety of equipment and fixtures. These items differ in their durability and use, and, therefore, each requires its own replacement timetable. We cannot emphasize enough the importance of caution when a hall requires minor renovations and replacements of hall fixtures or equipment. Even when the renovation work appears to be small in scale, or of a nature unrelated to the hall's acoustics, we strongly recommend consulting with the acoustician of the project. It is not unusual that minor changes to a hall's fixtures or equipment, or renovations seemingly unrelated to the acoustical design will have major unintended impacts on a hall's acoustics.

<< Renovating a Hall to Upgrade Acoustical Performance Characteristics >>

Many years after a facility is built, the sound sources used in the facility may change or other conditions in the room's use may shift, so that the acoustical performance characteristics of the hall may now be an impediment to the room's achieving its fullest acoustical potential. In these cases, acoustically appropriate renovations are clearly desirable.

One example of this kind of situation is a church or chapel that installs a pipe organ. The sanctuary now needs renovations to maximize the beauty of the pipe organ music. Another example of upgrade renovations to meet changing conditions is the installation of a sound amplification system to increase the audibility of sermons or other speech for aging audiences.

In some instances, the acoustical upgrade required enhances sound isolation, such as renovations to increase the sound isolation performance characteristic between music practice rooms to accommodate the very loud decibels of some contemporary music. Another kind of upgrade typically occurs in sports facilities. Originally, the facility may have been planned exclusively for individual or team practice and official games. Thereafter, the client wishes to use the facility for sports instruction. In this situation, the acoustical upgrades may focus on increasing the clarity of the spoken word so that students can hear and understand their instructors. Many other kinds of acoustical performance upgrades can be designed depending on the venues' specific requirements and objectives.

<< Correcting Acoustical Problems >>

Claims and complaints about acoustical problems touch on a variety of different issues. However, the most common claims mention one of the following problems: noise, sound leakage from one room to another, excess reverberation, and inability to hear human speech. Any of these claims can be raised about a variety of facilities including sanctuaries of houses of worship, indoor athletic facilities, exhibition halls and galleries, legislative chambers, and structures serving many other purposes. These kinds of claims typically come to light immediately after the completion of a building's construction, and it is not uncommon for discovery of the problem to then escalate to an investigation of who bears responsibility for the problem. In almost all of these cases, acoustics were not included in the requirements during the planning phase of the project.

Every building or structure must first meet certain pre-determined and appropriate performance criteria, including acoustical criteria, in order to function as intended. If a new hall will be built in a community cultural center, everyone understands the importance of the facility's acoustics to the overall success of the project. However, an understanding of the important role of acoustics in renovation projects is much weaker, and if the facility is not a hall for the performing arts, then even if the project is new construction, concern for the facility's acoustics is almost always ignored. It is my sincerest wish that more people will come to understand that the current manner of ignoring any building's acoustical considerations surely increases the need for remedial construction with all its accompanying frustrations and expense.

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Nagata Acoustics News 02-2(No.170)
Issued : February 25, 2002

Nagata Acoustics Inc.
Hongo Segawa Bldg. 3F, 2-35-10
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