Quietness, Comfortable Sound and Excellent Acoustics NAGATA ACOUSTICS

News 08-04 (No.244)

Issued : April 25, 2008

[ Japanese Version ]

Nagoya University's Toyoda Auditorium Renovation Project

by Akira Ono

The auditorium exterior
The auditorium exterior

The Toyoda Auditorium Renovation Project at Nagoya University began in December, 2006 and completed earlier this year, in February 2008. This article presents an overview of the renovation project and traces the auditorium's history and architectural lineage.

<< History of Toyoda Auditorium's Founding >>

Toyoda Auditorium was built in 1960 using funds that Toyota Motor Corporation donated to Nagoya University for the project at the university's request. In making the donation, the auto manufacturer decided to honor the memory of Sakichi Toyoda, the family patriarch whose Toyota Industries Corporation grew into today's Toyota Motor Corporation. Because the auditorium takes its name from the man, not the company, the auditorium's name is written in the Japanese language with the Chinese characters of the family name, instead of with the stylized phonetic spelling used by Toyota Corporation For the same reason, the auditorium name is pronounced "Toyoda," not "Toyota."

For the project architect, Toyota Motor Corporation proposed Fumihiko Maki. Mr. Maki was then Assistant Professor of Architecture at Washington University in St. Louis, Missouri and was working part time for the general contractor, Takenaka Corporation. Mr. Maki designed Toyoda Auditorium and Takenaka Corporation built it.

In the late 1950s, Nagoya University was the newest addition to the Japanese national university system that replaced the earlier imperial university system after the end of World War II. Nagoya University did not yet have a main campus; instead, it was spread across eight locations and was jokingly nicknamed "octopus-legged university." As a part of the school's plan to build a main campus and move its dispersed classrooms and programs to one site, the Toyoda Auditorium project symbolized the realization of this goal, and it was placed at a central location on the university's Higashiyama main campus.

<< Toyoda Auditorium's Architectural Design >>

Pilotis in the original building
Pilotis in the original building

The auditorium's architectural design intentionally draws attention to the textures of the brute concrete used as the primary building material and makes use of the freedom this building material gives the architect in creating the building's shape. In this sense, the structure closely resembles forms created by Le Corbusier and equally those of Kunio Maekawa, who studied with Le Corbusier.

Unlike the sophisticated materials, such as aluminum, and the refined orchestration of sharp and soft lines that we associate with the masterpieces of Mr. Maki's later-established architectural style, the Toyoda Auditorium design represents an earlier Mr. Maki, with a still raw and strongly youthful sensibility that gives the building a feeling of exuberance. At the same time, when we look at the front of Toyoda Auditorium, we are struck by the extremely horizontal and linear appearance the building presents, with its prominent pilotis supporting the long concrete span. In these elements we can see the connection between this early work by Mr. Maki and the refined style of his later architectural masterpieces.

In 1962, Toyoda Auditorium won the Architectural Institute of Japan Annual Design Prize. Mr. Maki was a young man when he was entrusted with this project's design and he clearly lived up to the aspirations of the university and patrons who commissioned him for the auditorium project.

<< Scope of Work for the Toyoda Auditorium Renovation Project >>

The auditorium interior before the renovations
The auditorium interior before the renovations

The auditorium interior after the renovations
The auditorium interior after the renovations

As with the original project, Toyota Motor Corporation, together with affiliated Toyota group companies, provided the financial resources for the renovation and expansion project. Maki and Associates served as the architect and Takenaka Corporation was the general contractor.

Nagata Acoustics designed and oversaw the implementation of the auditorium's acoustical renovations. Our work on this project included changes to the interior walls, new audience seating, a new sound system and noise reduction measures, as well as a range of room acoustics-related renovations.

<< Acoustical Renovation Goals and Accomplishments >>

The most visually obvious change to the auditorium's interior was our replacement of the audience seating area's sidewalls. Prior to the renovation, these walls were a mix of sound absorbing panels, numerous loudspeaker and other openings, and artfully designed sections with embedded tiles. The new sidewalls are a refreshingly consistent and attractive laminated surface.

We also replaced the audience seating. The new seats each have their own foldaway writing surfaces, LAN connections and AC outlets. We increased the legroom between rows to provide audiences a more comfortable hall experience. The change in legroom reduced the auditorium's seating capacity from 1,600 seats to 1,204 seats.

The pre-renovation sound system had sound reinforcement clarity problems, so one acoustical goal of the renovations targeted improving the sound reinforcement's quality, and specifically, its clarity. Our design and installation of the new sound system included the selection, placement and fine tuning of the auditorium's loudspeakers, resulting in a huge improvement in amplified sound clarity in the renovated auditorium.

Another acoustical goal of the project addressed HVAC noise. Before the renovation, the HVAC system produced noise levels of NC-45 to 50 in the auditorium. We replaced both the HVAC equipment and the ductwork, and the noise level decreased to NC-30 or quieter.

Our room acoustics renovations focused on the stage area. By adding sound-reflecting sidewalls to the stage we simultaneously answered the project objective of creating stage wings. In addition, behind the ribbed back wall of the stage we hung a retractable, sound-absorbing curtain. For symposiums and other speaking events, the curtain lessens the otherwise strong sound reflections, and the curtain can be stored away during concert programs. When the curtain is stored away, the auditorium's reverberation time measures 1.8 seconds. When deployed, the reverberation time measures 1.7 seconds. (Both measurements are at 500 Hz.) These results represent substantial quality improvements to the auditorium's room acoustics.

<< Opportunities for New Programming >>

Nagoya University professor, Dr. Hiroyuki Shimizu, specializes in research on the planning and operational activities of public cultural facilities. During the renovation project, he proposed numerous ideas about how to improve the functionality offered by the auditorium. For this renovation, the project sponsors prioritized improving the aesthetics of the facility and the project was not able to incorporate as many of Dr. Shimizu's suggestions as might have been included. Nevertheless, the project stimulated Dr. Shimizu to provide advice and I hope that he and others will continue to work with the university to increase the use of the auditorium beyond its traditional use for ceremonies to include a broader range of events and programs.

Nagoya University shows the school's affection for Toyoda Auditorium by prominently displaying a photo of the building on its home page. The URL is http://www.nagoya-u.ac.jp.

Four New Small Halls at Vienna's Musikverein

by Toshiko Fukuchi

The planning work for a new hall project recently afforded me the rare opportunity to visit the backstage areas of a number of halls in Vienna, Salzburg and Paris. I also participated in conversations with these halls' management. In this newsletter, I will introduce the reader to my observations from this trip.

In this article, I will focus on Vienna, the location of the hall often said to have the most beautiful acoustics and the hall famous for its annual New Year's concerts, the Vienna Musikverein. This time, however, I will not write about the Musikverein's main hall, but about the four basement-level halls completed in 2004. These halls were built under the road that runs between the front entrance of the Musikverein and the theater on the other side of the thoroughfare.

Initially, plans called for one rehearsal room to be built beneath the road. When the fundraising prospects exceeded expectations (and even though the actual donations did not meet the revised forecast), the plans changed and four rooms were built instead.

The four halls are named Glass Hall, Stone Hall, Metal Hall and Wood Hall. As the reader can guess from the halls' names, the interior of each hall uses the material for which each is named.

Glass Hall
Glass Hall
Stone Hall
Stone Hall
Metal Hall
Metal Hall
Wood Hall
Wood Hall

Glass Hall, the largest of the four halls, has glass panels installed on its ceiling and walls. The sparkling colors in this room shine as brilliantly as those of the main Goldener Saal. This room's ceiling has a height the equivalent of two stories, and the size of the room's footprint and the arrangement of the tiered risers for the musicians all match the setup of the main hall. Unlike in the main hall, the tiered risers are adjustable, allowing the hall's floor to be changed into a flat floor.

In Glass Hall, the wall facing the tiered area for the musicians has sound absorbing material (though it was not visible to me whether or not this material covers the entire wall), and in front of the sound absorbing material are convex glass panels constructed with sheets of gold-colored material sandwiched between two glass layers. A portion of these panels can be moved into open and closed positions and are used to adjust the reverberation characteristic of the room. A projection screen installed at the center of Glass Hall facilitates this hall's use for lectures.

In the other three rooms, the ceilings are lower than in Glass Hall. These rooms are appropriate for chamber music performances and parties and are outfitted for these purposes. The primary use of these halls appears to be as a venue for social gatherings; the space adjacent to Wood Hall is equipped with a permanent cocktail bar counter.

The materials used in each of the rooms reflect current architectural trends. Moreover, throughout the rooms, these materials have been adapted to achieve acoustical objectives. The novel uses made of materials, the halls' sound diffusing shapes, the way parallel walls were avoided in the rectangular rooms and the adjustable sound absorption mechanisms were some of the many details of these rooms that gave me ideas for future reference.The Musikverein's URL is http://www.musikverein.at/.

Installed Sound Systems/ Part 4: Current Constraints and Challenges of Speaker Installation Planning and Fine-tuning

by Makoto Ino

Last year, in this newsletter's May, 2007 issue (No. 233), I used Part 3 of this series to provide an overview of the operational and physical environments that influence loudspeaker selection and installation. This time, I will discuss speaker installation planning and fine tuning in more detail, focusing on the current state of the industry and related technological constraints and challenges.

The fundamental requirements of successful sound reinforcement include appropriate sound volume, sound quality, sound imagery and clarity, taking into consideration the kind of facility where the sound will be amplified and the programming held there. If we expand this general statement one big step further, we might say that sound reinforcement aims to achieve "naturalness," a vague term that we need to unpack. Our subjective impressions tell us that amplified sound's naturalness includes presence and personality, refinement (as opposed to coarseness), immediacy, warmth, fullness (as opposed to diluteness), strength and energy, sound imagery size and localization, clarity, balanced reverberations, separation and resolution. In addition, there may be other elements the reader might add to this list, as the definition of naturalness continues to expand like stones accumulating around the foot of a steep mountain.

Not only do sound system installations combine multiple pieces of sound equipment, but each piece of equipment has its own set of characteristics, making the potential total range of sound characteristics exponentially large. In each of the planning, installing, fine tuning and operating phases of a sound system installation project, we must continually balance the elements that comprise naturalness in order to ensure the project's success.

<< What Results Can Installation Planning Predict? >>

Fig. 1 - Plan view of an evaluation of loudspeaker coverage in a hall
Fig. 1 - Plan view of an evaluation of
loudspeaker coverage in a hall

Recently, even the field of sound system design has begun using computer simulation software to visually represent sound properties and conditions that are difficult to express quantitatively or with words. Sound system designers use the simulated visual representations to evaluate the sound properties and conditions and present them to clients and others. A variety of simulation methods and output formats exist, but for speaker installation planning, the sole benefit of using any of these simulation software applications is that they can display the distribution of sound pressure levels of direct sound. These applications were developed in response to a market need to visually represent variations in a space's sound volume. But I must emphasize here my earlier comment that in planning an installation we need to think holistically about the sound reinforcement quality and simultaneously consider balancing a range of properties and conditions. Current computer simulation software does not even begin to scratch the surface in meeting this need.

Because speakers are built of complex components, we cannot rely on the actual sound-wave motion produced by the speakers to make determinations about sound reinforcement in a space. Therefore, for line array speakers, we can only make simple predictions about the sound they will emit. This reality puts the development of more meaningful simulation software at an impasse.

A related issue concerns the data provided by speaker manufacturers about the directional characteristics of their products. When we listen to amplified sound, the sound quality, clarity, directional characteristics and other sound properties surely change depending on our distance from the speakers. But when manufacturers physically measure speaker sound pressure levels to obtain the directional characteristics data of their speakers, they measure at the distance most favorable for the product or at a distance that is convenient for the measuring task, and they use inconsistent methods from product to product and manufacturer to manufacturer. If a manufacturer measures speakers at a distance of 3 m. (10 ft) to obtain data on a product's directionality, can we reliably apply this data to how the speakers will sound in the many theaters and halls that have audience seating areas extending back more than 30 m. (98 ft) from the prosceniums where the speakers will be placed? Can we reliably apply the data to sports facilities where audiences may sit 50 m. (164 ft) or 100 m. (328 ft) from a speaker? Unless we have comprehensive knowledge of the properties and characteristics of speaker models, we will be hard pressed to select suitable speakers for installation in a specific space or to consider how to optimally place the speakers in the space.

In addition, amplified sound is greatly affected by the architecture and other physical properties of a space. Moreover, while we may make generalizations about the effects of room acoustics, when the specific characteristics and conditions of the reflected sounds change, we hear the amplified sound very differently even in the same architectural space. When we tune the sound quality (that is, adjust the frequency characteristics etc.), we experience more variations. Some manufacturers have attempted to provide a facile way for prospective customers to hear simulated model-based, amplified sound differences during product demonstrations. While such attempts are interesting as academic experiments, they ignore the current limitations of computer simulation software. Adopting these imprecise methods in the short term, just because they are readily available, creates an obstacle that impedes true technical progress in this field.

Computer simulation software is just a tool, and spending time bemoaning its current inadequacies won't aid us in making progress on our sound system design projects. Figure 1 shows an example of how we currently use the available simulation method. We add geometric representations of the speakers' directionality and coverage areas on the floor plan, and then we look for overlapping coverage and consider if the directions the sound will travel will result in it arriving to appropriate locations in the hall. We find this simple method most effective.

<< What Results Can the Fine Tuning Phase Achieve? >>

During the installation phase, we place all the equipment and establish all the connections. Then we turn on the whole system and hear sound. But at this point in a project, the sound we hear bears little resemblance to the fine sound we will achieve through the fine tuning process. To deliver good results, we must do a first round of settings followed by individual adjustments to each setting, followed by testing and more fine tuning. Through this process, we ensure that the sound system accomplishes the installation project's objectives, enabling us to complete our work and turn over operation of the sound system to the client.

The work we perform during the fine tuning phase is some of the most important work of an entire project and it is also generally undervalued and insufficiently understood. For the installation phase, we prepare specification documents to give to the installation crew, detailing the functional and performance objectives, including the expected measurable numeric and qualitative results required to complete the sound system installation. But the installers typically do not have the expertise to adjust settings based on their own listening and judgment. They also tend to mistakenly assume that by achieving the numeric values written in the specifications, they have accomplished all that needs to happen for the installation's success.

During the final testing, if we hear something that sounds less than perfect, we investigate it. There is always a root cause and we must persevere in finding it. We only consider a project complete when we have successfully adjusted the sound system's settings to optimally hear and balance all of the characteristics that create "naturalness." This includes both characteristics that can be measured numerically and qualities we must evaluate with our own ears. For example, there are currently no numeric values for quantifying the properties and conditions of a system's sound imagery, so the only way to evaluate the sound imagery of a sound system is to listen to the system. Moreover, we consider sound imagery to be a quality that contributes very significantly to the objective of "naturalness."

Equipment for fine tuning loudspeakers stacked in the center of an audience seating area
Equipment for fine tuning loudspeakers
stacked in the center of an audience seating area

During fine tuning, we begin by confirming the normal operating capability of each piece of equipment and between connected pieces of equipment. Then we set the equalizers and adjust the sound quality, after which we perform actual hearing tests in the hall while we make minor adjustments and complete the fine tuning. During this work, we always keep in mind the overarching goals of ensuring stable operation of the sound system, ease of operation by the client or the client's assigned representatives and either wide adaptability to different source sounds or adaptability to the anticipated performance genres, depending on the project programming. In summary, we prepare the sound system with a setup that becomes the system's standard for daily operational use.

Today, most digital sound system equipment adjustments can be done with a fine degree of precision from a PC or laptop computer. Of course, the adjustments do not occur automatically. Fine tuning results still rely on the hands-on experience and creative acumen of the sound system designer. Like the voicing work of an organ builder who fine tunes a pipe organ to the architectural and physical surroundings where it is installed, fine tuning ranks high among the essential tasks for successful installation of a sound system.

Nagata Acoustics Inc.
Hongo Segawa Bldg. 3F, 2-35-10
Hongo, Bunkyo-ku, Tokyo 113-0033 Japan
Tel: +81-3-5800-2671, Fax: +81-3-5800-2672

(US Office)
2130 Sawtelle Blvd., Suite 307A,
Los Angeles, CA 90025, U.S.A.
Telephone: (310) 231-7818
Fax: (310) 231-7816

E-mail: info@nagata.co.jp

[ Japanese Version ]