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

Nagata Acoustics News 04-01 (No.193)
Issued : January 25, 2004

Yamaguchi Center for Arts and Media (YCAM) Opens

by Dr. Keiji Oguchi

Yamaguchi Center for Arts and Media
Yamaguchi Center for Arts and Media (YCAM), a public-works project funded by Yamaguchi City, opened in November 2003. In the Yamaguchi City mayoral election held in April 2002, Mr. Eiichi Goushi successfully campaigned for the position on a platform that included a promise to reevaluate the YCAM project. After his election, the new mayor put the YCAM project on hold during the reevaluation process, creating a stir in the Japanese media that brought this facility to the attention of the entire nation. At the time that the project was put on hold, construction had already progressed to the stage that the building's steel frame was almost completely built.

<< The Project's Reevaluation Committee >>

In order to reevaluate the project, the city created a committee of 100 members, with the core committee participants selected from among local city residents. At the outset of the committee's work, Mayor Goushi addressed the committee and clearly shared his thinking on the objectives of the reevaluation, stating that the facility to be built must have a purpose and functionality that makes sense to the people of Yamaguchi City, has the public's support and will be used by the community at large.

Prior to the Mr. Goushi's election, the YCAM project plan included a plethora of terms such as "media art" and "multimedia," expressions that have a hi-tech sound and are mostly unfamiliar loan words from English. But these catchy words and phrases did not convey to the people of Yamaguchi City what activities would take place in the new center or what kind of facilities the center would have. It seems that a lack of communication was the root cause of the public's lack of understanding about the project's content.

<< The Reevaluation Committee's Pragmatic Recommendation >>

A look at the reevaluation committee's meeting minutes reveals that the participants offered a wide range of opinions on the appropriate direction the project should take. Since 100 people participated on the committee, it is natural that there were many different points of view. Overall, the committee's choices could be summarized into four categories: dismantle the structure and re-do the conceptual work of defining the facility's purpose; keep the structure but change the purpose of the facility to something other than arts-and-culture objectives; keep the objective of a cultural center, but reevaluate the contents of performances; or, continue the project as originally defined and designed.

In the end, the committee completed its work with a written report that, while recommending the option of proceeding with the exterior as originally designed and re-planning the contents of performances, also gives space to the other three approaches that it did not select. Upon receiving the committee's recommendation, and after a two-month hiatus of work on the project, the mayor gave the go-ahead for the project's construction to resume.

As for the changes to the center's original interior plans and design, community involvement and use became the underlying principle in developing the center's operational plans and the budget for center-sponsored operations and activities tightened. In terms of changes to the center's equipment and interior construction design, the changes were minimal and the center interior as well as exterior were able to be completed in March 2003.

<< Yamaguchi City's New Information Technology District >>

YCAM is located midway between a well-known hot spring named Yuda Onsen (which, according to Japanese legend, was discovered by a Buddhist priest when he saw a white fox curing its injured leg there) and the section of Yamaguchi City considered its "center," where prefectural and city government office buildings predominate.

One goal of Yamaguchi City has been to create a new focus destination in the area where it built YCAM, and YCAM is intended as one of the core attractions that will draw people to this part of the city. Immediately to the north of the YCAM site, a new headquarters is under construction for the Japan Broadcasting Corporation's Yamaguchi Prefecture affiliate. This new building's plans include a floor with interactive media for public use. Also, Yamaguchi Cablevision already occupies the land directly to the south of YCAM. Since the common link among these three new additions to the neighborhood is their involvement and connection with information technologies, they may well give this part of Yamaguchi City a reputation as the information technology district.

<< Three "Studios" and a Library Line Up Under an Undulating Roof >>

Section of YCAM
Inside YCAM, a library and three performance spaces called "studios" line up side by side, like a row of railroad cars. The project's architect, Mr. Arata Isozaki, designed the center's roof with an undulating shape that spans the entire building, echoing the mountain vistas of Yamaguchi City's natural surroundings. (The name "Yamaguchi" is written with the Chinese characters for "mountain" and "entrance/mouth.") Mr. Isozaki cleverly aligned the high points of the roof and the interior layout of the center so that the space beneath the peaks functions as the flies needed by the theater (Studio "A") and provides sufficient height for the flat-floored Studio "B."

The center's exterior walls are constructed of patterned glass, forming a glass curtain-wall along the sides of the building. Glass is also used as a divider between some of the building's spaces to create interior courtyards that bring an abundance of natural light into the building. The glass curtain-walls created one of this project's design challenges, because they required that special consideration be given to effective means of shutting out outdoor light and to obtaining the desired sound isolation for the performance spaces.

<< Theater Studio "A" >>

"Studio A," the largest of the three performance spaces, has pneumatically powered, configurable audience seating. The seating is fixed on palettes that can be raised and lowered using pneumatic devices. By maximally lowering the seating below the theater's floor level, the theater can be transformed into an 800 sq. m. (8,611 sq. ft) flat-floor hall.

When Studio "A" is set up with an end stage and tiered seating, the seat count is approximately 500. The room's interior is appropriately finished in black and dark tones for theater use.

Likewise, our acoustical design for Studio "A" is geared to theater use. Both the ceiling and the walls are covered with acoustically absorbing materials to control reverberation. The reverberation time of Studio "A" measures 0.7 seconds when the hall is configured with tiered seating and the room is unoccupied.

Studio A & Studio B

<< The Glass Walls of Flat-floor Studio "B" >>

The color scheme of Studio "B" contrasts with Studio "A" by being mostly a white space intended for exhibitions, performances that involve body movement and video/film showings. The room configuration is a box shape. The south wall of Studio "B" has glass panels that face onto one of the building's interior courtyards, which is sandwiched between Studio "B" and the library. The north wall of Studio "B" faces onto another interior courtyard, which is sandwiched between Studio "B" and the center foyer.

At both the north and south walls of Studio "B" we installed room dividers that can be rolled out along fixed rails to cover the glass walls and transform Studio "B" into a room with four white walls. Our programming work to understand how Studio "B" will be used determined that some performances and events held in the space will surely generate very loud sound, so we made accommodation for very loud sound by designing the room with a box-within-a-box, anti-vibration and sound isolation structure. We implemented the box-within-a-box design by using anti-vibration-rated rails for the room dividers that cover the glass walls. When the room dividers are rolled out and cover the glass walls, the room becomes a box-within-a-box structure.

<< Film Theater Studio "C" >>

Studio "C" has fixed seating for 100 persons and is intended as a cinema and lecture hall. This hall's acoustics and seating design are similar to those used in recently built commercial cinema complexes, with the floor, walls and ceilings all covered with sound-absorbing materials and comfortable, generously proportioned seating.

<< The Community Takes on Performance Production Planning >>

Most unusually for a publicly funded facility, from the earliest construction phases of the YCAM project, the center has had the benefit of two professionals to guide the development of its ongoing performance production planning. One of these individuals is Mr. Junya Yoshimitsu, who has taught at Yamaguchi University. The other person hired by YCAM to direct planning and operations is Mr. Masahito Kishi, who came to YCAM after years of experience at Public Theater in Tokyo's Setagaya Ward.

As a result of the reevaluation of the original plans for the center's interior design and ongoing operations, a board comprised of community members was established to provide advice, modifications and direction to the performance production plans and operational activities devised by YCAM's professional staff. In addition, a separate committee, also made up of local citizens, conducts surveys and gathers information on community needs and desires in order to align YCAM's performance production planning with performances and events of interest to the general public.

<< YCAM's Opening Series, Including Contemporary Media Arts >>

One of the contemporary media art works included in YCAM's opening series was an interactive art installation entitled "Amodal Suspension -- Relational Architecture 8" by Mexican artist Raphael Lozano-Hemmer. In this work, messages sent via cell phones were converted to flashes of light that played across the night sky as they were sent to the receiving cell-phone numbers. Another contemporary work included in the YCAM Opening Series was a work by Philippe Decoufle, entitled "Iris," that combines live dance with projected images of pre-recorded movement.

YCAM's Opening Series combined best-in-class contemporary media art with other programs and exhibits targeted at pleasing families with children, as well as showings of films by Yasujiro Ozu (1903-1963), one of Japan's most internationally venerated film directors, projected on a wall of YCAM's foyer. The atmosphere at Opening Series programs apparently confirmed that everyone who attended them enjoyed themselves, and community board members also gave the Opening Series high marks. After a rocky beginning, YCAM seems to have hit its stride and is being received as a wonderful addition to the cultural life of Yamaguchi City. I hope that it continues to enjoy the appreciation of the people for whom it was built.

Recent Trends in Assisted Hearing Systems

by Masaya Uchida

In recent years, many Japanese facilities and venues have made good progress in creating a barrier-free environment for people with disabilities. The inclusion of an assisted hearing system in hall sound system design has already been standard procedure in Japan's public halls and facilities for quite some time, due to the public-use nature of these projects and the requirement that audience participants with hearing disabilities be able to hear the amplified sound clearly.

When we refer to the term "hearing impaired," however, we include people with a wide spectrum of conditions, from difficulty hearing softly spoken conversation to severe impairments that prevent individuals from hearing rather loud sound. People may often equate the hearing impaired with the population of people who use hearing aids, but among people who have minor hearing loss, many do not use hearing aids. Exact statistics are not available, but reports estimate that approximately six million Japanese (about 5% of the population) have minor or severe hearing loss. As Japan's population continues its aging trend, the number of people who experience hearing loss due to old age is also likely to grow.

For all of these groups of people, assisted hearing systems provide important hearing support by transmitting to headsets or hearing aids the sound that is selectively captured by a microphone or generated by a sound system. In this article, I will review the three technologies currently available for assisted hearing systems.

<< Magnetic Induction Systems >>

Magnetic induction assisted hearing systems use a loop antenna installed around the audience area (often embedded under the floor), which transmits the sound signals produced during a performance or event to a receiving induction coil in a hearing aid. An advantage of this kind of system is that any induction-coil hearing aid can be used without extra devices (including both hearing aids worn over the ear and pocket models, types that are used by people with moderate to severe impairment). This feature means that hearing impaired audience participants can use their own hearing devices. In the past, magnetic induction assisted hearing systems were the most frequently installed systems in Japan.

The disadvantages of a magnetic induction system are: (1) incompatibility with in-ear hearing aids that do not have coils; (2) inability to be used by people who do not normally wear a hearing aid but have minor hearing loss; (3) degradation of sound quality due to magnetic induction's physical properties; and (4) users' inconsistent sensory results depending on how the hearing aid is attached to the body and also depending on the hearing aid model. While the technology is simple, the cost of laying the antenna can be a factor in implementing this kind of system. For large-scale halls and facilities, a limited portion of the audience area is often designated for installation of the loop antenna. Currently, about one half of all new projects in Japan still implement magnetic induction systems because this technology is the standard way to comply with assisted hearing requirements. However, from a performance perspective, the radio signal and infrared technologies that I will discuss next are undeniably superior to systems that use magnetic induction technology.

<< Radio Signal (RF) Systems >>

In assisted hearing systems that use radio signal technology, a transmitter sends the sound signal across radio waves (either at 300 MHz band or using the 75Hz frequency band reserved in Japan for educational and welfare use) to a special receiver. The technology offers the following advantages: (1) The system delivers good sound quality. (2) The receiver can be connected to earphones and used by people with minor hearing loss who do not normally wear hearing aids. (3) If an inductor is added, people with coil-type hearing aids that rely on magnetic induction can also receive the transmitted sound signals. In addition, within the area that receives the transmission, there is no need to limit or pre-define specific seats for assisted-hearing use.

One limitation of the radio signal technology system is that, in general, the transmitter's range only reaches as far as 30-to-50 meters (98-to-164 ft), making its use appropriate to small and medium-size facilities. Balancing this limitation is this technology's easy installation. A single, small transmitter can be installed without major construction and with only minimal impact on a facility's architectural design. It is also easy to install as a retrofit to an existing structure.

Radio signal assisted hearing systems have the following disadvantages: (1) The natural characteristics of radio signals give rise to "dead points" where the signal cannot be received (as occurs with some cell-phone systems). (2) Signals from strong external sources, such as the radio signals sent by truckers, can produce noise on the receivers. (3) The use of special headsets means that a facility must lend/rent equipment as well as store and maintain it. (4) Hearing impaired audiences must also accept and accommodate the use of extra headset equipment.

From a financial perspective, the cost of the radio signal devices for heavy-duty commercial use (especially the receiver units) can be expensive, making the overall cost of implementing a radio signal assisted hearing system as expensive as a magnetic induction system. However, for small-scale, public welfare facility applications, there are inexpensive models that are ideal for this purpose. Also, some new hearing aid models that have come on the retail market include FM signal receivers, so one possible future development may be compatibility between radio signal assisted hearing systems and individually owned hearing aids.

<< Infrared Systems >>

Infrared-technology assisted hearing systems transmit infrared signals from infrared radiator panels to specialty receivers that, like the receivers for radio signal systems, can be attached to a wide variety of headsets, earphones and in-ear devices. The sound quality is good enough that this is the same technology used in wireless headphone equipment aimed at the audiophile market. In addition to excellent sound quality, the other advantages of infrared systems are: (1) stable reception with minimal variation among seat locations; and (2) easy expansion of the system's coverage area throughout even large-scale auditoriums. Coverage can be expanded simply by installing additional radiator panels.

A further beneficial characteristic of infrared signals is that they do not transmit through walls. A single infrared assisted hearing system can be used in adjacent rooms without any interference or crossover of the sound signals, through the use of multi-channel signaling. For this reason, infrared signal technology is already the predominant technology used for multilingual simultaneous interpretation systems. Another capability of some infrared receiver units is stereo reception. Infrared technology has been robustly adopted and applied to numerous devices with strong performance capabilities and functionalities.

The relatively easy installation of an infrared assisted hearing system requires only hanging the infrared emitter panels on walls or ceilings and running electricity to them. However, this kind of system also has its drawbacks: (1) Hearing-impaired audience participants must use specially equipped receivers (as is true for radio signal systems). (2) The infrared systems do not work where there is direct sunlight, so precautions are needed to shut out direct sunlight. (3) The cost of infrared system equipment is expensive. With regard to the third, financial drawback, recent progress in producing less expensive infrared systems has made the cost of installing an infrared system comparable to the cost of a magnetic induction system.

<< Choosing the Right Assisted Hearing Receivers for Public Halls >>

When public halls in Japan install an assisted hearing system that requires special receivers, they typically purchase about 10 units or 3-to-5% of an auditorium's seat count. Also, because the in-ear parts and earbuds typically included with receiver equipment raise hygiene-related concerns when used by multiple individuals, public halls should choose headphones that fit on or over the ear for shared public use. In addition, from the hearing-impaired user's perspective, the best sound will be obtained from headphone styles that seal the area around the ear from ambient sound and that cover both ears. However, an extra hurdle exists with dual-ear headphones because of the monaural characteristic of most assisted hearing systems. Currently, a stereo-monaural connector must be added to dual-ear headphones to make them compatible with monaural assisted hearing devices. I am sure that users would be grateful if the equipment manufacturers would work to eliminate this impediment.

<< Halls' Assisted Hearing Systems Need More Publicity >>

Assisted hearing systems are installed in many of Japan's public auditoriums, but their availability remains mostly unknown to the general public and, consequently, installed assisted hearing systems remain underused. People who use assisted hearing equipment appreciate it greatly, and most people who use assisted hearing equipment once choose to use it again the next time they have the opportunity.

A more proactive approach is needed to promote use of assisted hearing systems. One way to do this would be to post information about their availability at auditorium entrances. For venues that have a radio signal or infrared system, the auditorium needs to lend headphones to audience participants who want to use the assisted hearing system, and this means establishing processes and policies for the distribution, return, storage and maintenance of the headphone receivers. While most halls operate with a skeleton staff of employees who may be understandably reluctant to take on such added responsibilities, the use of assisted hearing systems can only be encouraged if halls address the operational and maintenance aspects of making headphones readily available. Lastly, in order to make assisted hearing systems more widely used by the many people who can benefit from them, the equipment manufacturers need to pursue enhancements that make the systems easier for both the hearing-impaired and hall operations management to use, and the prices of these systems must come down to levels that make them more affordable.

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Nagata Acoustics News 04-01 (No.193)
Issued : January 25, 2004

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