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

Nagata Acoustics News 01-5 (No.161)
Issued : May 25, 2001

Yamagata Terrsa Hall Opens in New Labor and Community Welfare Center

by Masaya Uchida

On April 1, 2001, a new Labor and Community Welfare Center opened its doors in Yamagata City. Employment and Human Resources Development Organization of Japan and Yamagata City jointly planned the facility, which is known by the moniker "Yamagata Terrsa."

The "Terrsa" labor and community welfare centers are a series of public works projects planned by Employment and Human Resources Development Organization of Japan and built in communities throughout Japan. "Terrsa" is an acronym meaning "town employees' relax, refresh and social amenity." "Yamagata Terrsa" is the last facility constructed as part of this initiative.

<< Choosing a Specialty Concert Hall Instead of a Multipurpose Hall >>

All of the previously built Terrsa facilities were designed with multipurpose halls for use by the local communities. What makes Yamagata Terrsa different is that the planners chose to include a classical music concert hall instead of a multipurpose hall. The primary reason the planners made this decision is the active presence in Yamagata of the professional Yamagata Symphony Orchestra.

Until Yamagata Terrsa opened, the Yamagata Symphony Orchestra performed at various publicly owned hall venues in Yamagata City, all of which are multipurpose halls, so the orchestra yearned for a concert hall with acoustics more suited to its performances. At one time, the city government had considered sponsoring the construction of a concert hall, but this never came to fruition. When it came time to plan Yamagata Terrsa, the city was able to make the concert hall construction a reality.

During the conceptual phase of the project, the planners first considered the development of a multipurpose hall with retractable, sliding reflection panels as the orchestra shell. However, in order to achieve a balance between the new Yamagata Terrsa facility and the city's existing venues, and to clearly differentiate the new hall from the city's multipurpose halls, the project planners opted for a true concert hall.

<< Yamagata Terrsa Project Summary >>

Terrsa Hall
Yamagata Terrsa's "Terrsa Hall" is an 800-seat concert hall. In addition to this main hall, the building has a rehearsal room, the 400-seat, multipurpose room named "Applause," conference rooms, a lounge, a fitness club and a restaurant, as well as the office space for the local unit of Employment and Human Resources Development Organization of Japan. Yamagata Terrsa is also set up to provide ongoing career and job opportunity information, physical rehabilitation and wellness training, adult education courses, and other programs consistent with community expectations for a comprehensive Labor and Community Welfare Center.

A consortium of Gendai, Itoh and Honma design management companies were responsible for the project's architectural design management, and Obayashi, Asanuma and Chitose general contractors were jointly in charge of construction. The theater-design planning consultant was Theater Workshop, and Nagata Acoustics provided the acoustical design, management and evaluation expertise.

<< Noise Prevention Strategies for Terrsa Hall >>

The Yamagata Terrsa project site is located near Japan Railroad tracks. As prevention against solid-state noise transference to the hall, the project's design plans located the facility's parking structure on the land nearest the train tracks and the facility's building as far from the tracks as possible. There is a distance of approximately 80m (262 ft) between the railroad tracks and the side of the Yamagata Terrsa building that is closest to it.

The interior architectural design of Yamagata Terrsa includes a main lobby that divides the building into north and south halves, thereby clearly setting apart Terrsa Hall from the building's other rooms and facilities. We designated the use of expansion joints in this area of the structure to prevent noise and vibration generated in the southern part of the building from reaching the concert hall.

<< Terrsa Hall's Acoustical Room Design >>

Terrsa Hall's shape is based on the traditional shoebox configuration, with a rectangular orchestra-level seating section and one balcony that has seating along both side walls as well as at the rear of the hall. The hall's ceiling is appropriately designed to be as high as possible, in keeping with the specialty concert hall character of the hall. In addition, in order to promote diverse timing distribution of sound reflections to the audience seating areas, the ceiling was designed to slope gently, in stages, from both the front and rear of the hall, with a central peak at the center of the hall.

Terrsa Hall is 20m (66 ft) wide x 38m (124 ft) deep. The ceiling height measures 13m (43 ft) above the stage floor and 17m (56 ft) above the audience area floor at the hall's center. Per person volume for the 800-seat hall is approximately 13 cu.m (459 cu. ft).

Much of the hall's interior surfaces are finished with ribbed wood-product paneling. To promote sound diffusion in the hall, we specifically designed the ribbing of the panels to have six differently shaped facings, installed in a random assortment throughout the hall. Behind portions of the ribbed paneling we also inserted some glass wool to achieve the addition of a sound-absorbing element to the hall without negatively impacting the hall's interior decor. Behind the ribbing at the rear of the stage, we installed a sound absorbing curtain that enables the hall to make small fine-tuning adjustments to the hall's acoustics to best match the needs of different performance programs. Terrsa Hall's reverberation time is 1.9 seconds (at 500 Hz, in an empty hall.)

<< Terrsa Hall's Sound System >>

The design of Terrsa Hall's sound system focused on achieving three main objectives: (1) the clarity of amplified speech; (2) high quality recording capability; and, (3) the ability to use the hall as a venue for live broadcasts. To obtain excellent clarity of amplified speech despite the hall's long reverberation time, we distributed the placement of the hall's main speakers across the entire ceiling area. This strategy shortens the distance from any audience seat to the nearest main speaker and also ensures that the amplified speech reaches all sections of the audience seating equally well. We also made accommodation for the now popular practice of combining concerts with pre-concert talks or other combinations of musical performance and spoken commentary by providing additional deployable speakers finished with the same wood finishing as the concert hall's interior surfaces. These speakers can be brought out on stage without disturbing the classical music concert hall ambience of the setting, because they blend perfectly with the hall's decor.

For recording purposes, we installed a suspended three-point microphone, placed slightly forward of the front of the stage, as well as three suspended one-point microphones at key positions directly above the stage. We also arranged for the installation of a separate sound mixer reserved exclusively for recording purposes, supplementing the sound mixer installed in the hall's sound room. The sound room's mixer is intended for use in adjusting the sound system for the benefit of live audiences. Additionally, we ran the acoustical-quality conduits and electrical circuits into the hall's large green room, so that this space can also be used for professional recording purposes.

In order to make it possible to broadcast live concerts from Terrsa Hall, we installed a receptacle panel at the hall's loading dock and laid audio cables between the panel and the hall stage and the recording and control rooms. In our design of these portions of the cable routing, we considered it such that divide the lines for in-hall use and the lines for recording or live broadcast use clearly and hall staff or others do not get confused.

<< "Applause," Yamagata Terrsa's Multipurpose Room >>

Yamagata Terrsa's multipurpose room, named "Applause," is located on the third floor of the new labor and community welfare center. This versatile space has a stage that can be raised or lowered, so that it can be made to "disappear" by setting its height level with the rest of the room's floor. The stage is basically an "open stage" design without a proscenium, but can be changed to a proscenium stage by rotating the sidewalls and ceiling around the stage. The room's audience seating is also not fixed, but can be removed to suit each event's needs. Applause also has a double layer of sliding wall partitions that divide the room in half for use as two separate, smaller spaces. Examples of the many possible uses for this space are: training seminars, lectures, parties, non-elaborate dramatic performances, and piano and other music recitals.

These features of variable room configurations required us to give special attention to the interior materials in the room. Our aim was both to realize an appropriate reverberation time when the entire room is used in its concert configuration and to prevent the reverberation time from being too long when the entire room is used in its lecture configuration and when the room is divided in half and one or both of the smaller spaces are used for other purposes. Our strategy was to have the sliding wall partitions fabricated of perforated board filled with glass wool, thereby making them absorptive surfaces. Applause's reverberation time is 1.4 seconds when the stage is lowered flat with the floor and the seating is removed, 1.2 seconds when it is set up in its concert configuration, and 1.0 seconds when it is set up for lecture purposes. (All measurements are without the wall partitions, at 500 Hz, with the hall empty.)

<< Applause's Sound System >>

We provided two groupings of speaker equipment for use in the Applause multipurpose space. For use when the room is set up with its stage, we implemented proscenium-center, side and fixed feedback speakers. For use when the room is set up with a flat floor and no stage, we installed ceiling speakers. We also provided movable speakers for use in conjunction with the ceiling speaker when the room is divided in half, and the sound system has a rolling cart that contains a small sound mixer and sound reproduction equipment, to further accommodate the partitioned room arrangement. This equipment can easily be moved into either of the partitioned halves of the room. Our overall focus in designing the Applause Sound System was to implement a simple system that is easy to use by the local community groups and organizations expected to book events in the room, as well as to provide flexibility and adaptability that will meet a wide variety of sound system needs.

<< Yamagata Symphony Orchestra's Terrsa Hall Inaugural Concert >>

On March 22, 2001, following the inaugural ceremonies, the Yamagata Symphony Orchestra performed its first public concert in Terrsa Hall, under the baton of Juichi Sato. The concert was a brief program of four works, lasting about 30 minutes in all, and included Strauss' "Die Fledermaus" Overture, Op. 362. The hall's acoustics exhibited excellent balance between low and high sound registers, as well as a comfortable balance between the sense of sound clarity and the sense of being surrounded by the music. While listening to the speeches during the inaugural ceremonies, I had the satisfaction of confirming the clear and easy listening quality of amplified speech in the hall.

After its official inauguration, Terrsa Hall scheduled a series of hall tours and other opportunities for the public to visit the hall and, on May 22, held a gala opening concert by the Yamagata Symphony Orchestra, and featuring piano soloist Alicia de Larrocha. With the hall's close ties to the locally based, professional Yamagata Symphony Orchestra, we have high expectations that Terrsa Hall will be a well-used, well-loved hall in Yamagata City.

Additional information about Yamagata Terrsa and Terrsa Hall can be found (in Japanese) at www.yamagataTerrsa.or.jp. The facility's phone number is 23-646-6677

Improving the Acoustical Environment in a Pachinko Parlor

by Katsuji Naniwa

This case study discusses work we implemented at a pachinko parlor located in a crowded and bustling shopping area just a few minutes' walk from the commuter train station of a bedroom community near Tokyo. The situation that led to an acoustical project at such a seemingly unlikely venue is as follows.

<< Project Background >>

Shortly before Nagata Acoustics was contacted, a competing pachinko parlor located even closer to the train station than our client's business remodeled its parlor, giving it a fresh, new look. Our client noted ruefully that his competitor's combined advantage of a more prime location and a new decor was drawing in more clientele, decreasing the popularity of our client's parlor.

Our client's competitor had used the strategy of an interior and exterior cosmetic makeover in order to attract a larger clientele. In response, our client decided that rather than trying to outmatch the competition with his own round of architectural design changes, instead, he would spend his budget on improving the sound environment inside his pachinko parlor.

<< A Pachinko Parlor Owner with a Love of Fine Music and Acoustics >>

Even before our client needed to overcome a competitive threat, he had apparently thought frequently about how he might improve the sound quality of the background music and announcements heard in his pachinko parlor. Since our client is a devotee of classical music, his motivation probably stemmed primarily from his personal sensitivity to fine acoustics. But since he also owns a foreign language school, it is clear that this pachinko parlor owner has a broader cultural vision than one would expect from a person in the arcade-type, pachinko parlor business. His wide-ranging interests may also have played a role in igniting his creative decision to improve the pachinko parlor's acoustics.

<< The Power of the Internet Brought this Client to Us >>

Nagata Acoustics' introduction to our pachinko parlor client came as an unsolicited inquiry from the pachinko parlor facilities manager, whom the owner had put in charge of the parlor's sound equipment renovation project. The facilities manager read about Nagata Acoustics on our company website and gave us a call.

We learned that the facilities manager had turned to the Internet somewhat out of desperation when his discussions with audio equipment manufacturers and equipment installation contractors failed to solve his sourcing requirement for the expertise his project needed. Since the manager himself had no prior experience with sound equipment renovation or acoustical improvement work, he was at quite a loss as to where to turn for help until his internet search led him to the Nagata Acoustics website.

<< The Pachinko Parlor's Pre-renovation Speaker Placement >>

The pre-renovation pachinko parlor used a large number of 12 cm (5 in)-diameter, high-performance speakers hung visibly from the ceiling throughout the parlor. The total number of speakers was about 30 units. There was no problem with the quantity of speakers, but we needed only one look at their placement and direction to know that these were inappropriate. In addition to the specifics of where on the ceiling the speakers had been installed, the speakers were turned so that they mostly did not face in the direction of the pachinko-playing customers.

The parlor's pachinko machines are arranged in banks of two rows each, with the backs of each two-row bank of machines facing together. (For those who are unfamiliar with pachinko machines, they are similar to vertical pinball machines. Individual players sit in front of the machines in a configuration similar to some slot-machine areas at casinos.) The parlor's speakers were installed close to the banks of pachinko machines and many were directly above the pachinko machines. The speakers were not turned toward the customer seating, but either toward the walls or toward the pachinko machines.

<< The Effects of Pointing Speakers in the Wrong Direction >>

We could understand the reason for the placement of the speakers near or directly above the pachinko machines. This was a safety measure that prevents the possibility of a customer being hit on the head by a speaker if one becomes loose and falls, a valid concern in earthquake-prone Japan.

However, pointing the speakers toward the walls or at the pachinko machines was beyond our comprehension, considering its impact on the valuable sound quality that leads people to select a good, high performance speaker. Even if the intention was to create an unobtrusive tone for the parlor's service announcements, or if for some reason there was a desire to diffuse the sound so that it sounded consistently flat and uninteresting, not directing speakers at the intended audience is unthinkable from an acoustical perspective. (Nevertheless, when we later did an informal survey of other pachinko parlors, we saw that this placement and "unthinkable" angling of the speakers is very much the norm at this kind of establishment.)

<< Sound Level Creep and Distortion >>

Because of the placement of the speakers and how they were angled, customers found it difficult to hear the parlor's announcements and the background music. Invariably, the response in this kind of situation is a vicious circle in which the sound volume is raised, creating a noisy atmosphere and damaging the clarity of the amplified sound, leading to another round of increasing the sound volume. The loud sound level also impairs the ability of the pachinko parlor's employees to communicate with each other using the wireless intercom handsets that they rely on while working in different parts of the parlor.

<< The Pre-renovation State of the Sound System Components >>

The pachinko parlor's CD player and sound mixer were severely worn, despite their relative newness. In addition, the equalizer that should have helped to improve the quality of sound reproduction from the speakers was inappropriately set, so it failed to provide any benefit.

<< Equipment Maintenance Expectations >>

I was in for a surprise when I looked behind the sound system components rack and in the area behind the counter near the parlor entrance where control equipment for the pachinko machines was located. Unlike the orderly, sometimes polished and finely trimmed set up we are used to seeing at concert halls and theaters, the wires and connections and circuitry looked as if they had been left exposed, after the electrical work was completed, without any attempt at concealment.

While there is probably nothing intrinsically wrong with a bare-bones approach to wiring, I queried the parlor's maintenance manager about what I saw and learned that a more serious and fundamental problem was the root cause of the parlor's exposed wiring. According to the maintenance manager, the pachinko machine manufacturers and maintenance technicians are undependable. They do not respond promptly to calls for service, their problem solving of equipment trouble is weak and their technical expertise is questionable. From the manufacturers' perspective, the pachinko parlors' operating methods are undoubtedly difficult to comprehend and the maintenance personnel might well point out that it is difficult to provide excellent servicing because pachinko parlors only allow them to do their work when the parlors are closed to customers, typically from 11:20 in the evening until 10 a.m. Whether these are reasons or excuses depends on which side one asks. The pachinko parlor managers have few good words for the pachinko machine manufacturers.

<< Selecting an Implementation Contractor for the Project >>

Given the uncertainties around the maintenance service providers, we decided that before planning the acoustical renovation design strategy, our first step should be to select a contractor or vendor we could trust with implementation of the design. Among the candidates were the parlor's current maintenance company, the companies that were involved in the original construction of the pachinko parlor, and a company that rents, operates and does construction for and installations of sound equipment. The operations manager of the pachinko parlor introduced this last candidate to us.

In comparing the candidates, we detected a concern for sound quality only in the approach of the sound equipment installation company's work proposal, which contained a section entitled "how to achieve good sound." We easily concluded that this company was our best choice for implementing the renovation project.

Working with our pachinko parlor client made us aware of how little is known about the acoustical consulting profession among the general public. Initially, the pachinko parlor owner assumed that we would be directly responsible for all construction and implementation required, as well as for the acoustical design for the project. In his mind, the project would be more straightforward and less complicated if Nagata Acoustics would be responsible for all aspects of the project. By spending time with the client to discuss our proper role, we successfully gained his understanding and the selected implementation company was hired for the project's execution.

<< The Sound System Renovation Goals and Strategy >>

Together with the client, we agreed on the following goals for the project::

(1) Provide the pachinko parlor customers with good and consistent quality sound.

(2) Ensure that the sound quality at the entrance to the Pachinko Parlor created a positive first impression. (This was an especially strong concern of the owner.)

(3) Improve the sound quality of verbal announcements broadcast over the sound system while background music is playing.

We decided to use the current locations of the suspended speakers as a starting point and to focus on improving the speakers' performance. With regard to sound volume, while we obviously wanted the sound to be loud enough for customers to hear the background music and announcements, our plan was not to increase the sound level, but rather, to decrease it.

<< The Renovation Plan: Directional and Frequency-related Changes >>

In our renovation design specifications, we pointed the speakers in the direction of the pachinko customers. Also, while retaining the full-range speakers in use before the renovation, we added subwoofers to augment the lower sound registers in the amplified sound-frequency characteristics, thereby relatively lowering the mid-range and high-range sound levels. One beneficial effect of the subwoofers was to give both the background music and the broadcast announcements a more natural tone. We installed the subwoofers above the banks of pachinko machines and facing the ceiling. The ratio of full-range speakers to subwoofers is generally about one subwoofer for every seven-or-eight full-range speakers. For this project, we proposed the installation of six subwoofers.

<< The Renovation Plan: Mitigating Speaker Interference >>

Another important piece of our renovation plan was to minimize fuzzy and deteriorated sound quality due to sound interference generated between and among the speaker units. We accomplished this using digital signal processors (DSPs). We divided the speakers into as many finely defined groups as possible for the purpose of assigning them to the DSPs, which contain delay and equalizing functionality. For this project, we used a ratio of four speakers per DSP, and we added additional electric power supplies to make up for the extra load of the increased channels. We also proposed replacing the worn CD player and sound mixer.

Due to the client's budget limitations, the project was implemented without replacing the worn CD player and sound mixer equipment. Instead of the proposed six subwoofers, four subwoofers were installed to complement the approximately 30 full-range speakers.

<< Post Installation Fine Tuning of the Speaker System >>

The primary focus of the post construction fine tuning was to achieve excellent articulation for the pachinko parlor's verbal announcements and clear-sounding background music through the elimination of any "booming" phenomena and by appropriately setting the subwoofer volume levels. Because of the addition of the subwoofers, we discovered that we needed to adjust the equipments' settings to boost the high frequency sound ranges of the full-range speakers. This was a natural consequence of the effect of the subwoofers, which gave a lower-range emphasis to the overall sound balance.

<< Evaluating the Renovation Results >>

After we completed the fine tuning adjustments of the sound system, we arranged for the facilities manager to test what we had accomplished. After the pachinko parlor closed for the evening, the employees remained on site, kept the pachinko machines running as they would be during normal operating hours, played background music CDs, made announcements and used their wireless intercom handsets. Everyone listened for the clarity of the announcements and the background music, as well as the ease of hearing one another on the wireless handsets.

From the after-hours test, the pachinko parlor owner and his employees happily recognized both improvement in the sound quality and the enhanced clarity of the background music and announcements. They noted that while the sound was clearer, the sound volume was lower, making it easier to hear.

Some days later, the client invested in a new CD player. I was on hand to observe the turn-up of this new piece of equipment. The client was visibly impressed by the difference this one piece of equipment made in further improving the overall quality of the sound system. His experience is likely to speed up his future plans to replace other components of the sound system with upgraded equipment.

This project challenged us to apply our acoustical consulting expertise to a very different environment than we find in concert halls and theaters. Pachinko parlors are naturally noisy places, where thousands of little, shiny, silver-colored metal balls race through pinball-like gates. People walk back and forth carrying buckets of their accumulated metal balls to be counted for prizes, or buckets full of newly purchased balls to start the game anew. Without altering the given situation, we used our skills to provide announcements and background music of good sound quality. Throughout the project, we kept ourselves aware of the client's needs and we prioritized understanding the special conditions under which our work and advice would benefit his objectives.

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Nagata Acoustics News 01-5(No.161)
Issued : May 25, 2001

Nagata Acoustics Inc.
Hongo Segawa Bldg. 3F, 2-35-10
Hongo, Bunkyo-ku, Tokyo 113-0033 Japan
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