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

Nagata Acoustics News 97-6iNo.114j
Issued : June 25, 1997

Completion of "CUBE" (Shiroishi Culture and Athletic Center)

by Akira Ono (Overview, The Glass Concert Hall, Room Acoustics, Pipe Organ, Hall Inauguration and Programs) & Motoo Komoda (Electrical Acoustic Equipment and Facilities)

1st Floor Plan
CUBE (Exterior)
Overview CUBE is the name of the newly completed cultural and athletic facility adjacent to Shiroishi-Zao Station along the Tohoku Shinkansen Bullet Train line in northern Japan. The official opening of the facility was May 4, 1997.

Hideto Horiike + URTOPIA Inc. created CUBE's architectural design. The exterior of CUBE's simple looking structure is glass and cement board. Approximately one-third of the foundation floor space is given over to a glass-encased concert hall seating 610 and a cafe suspended in space, known as the Cosmos' Egg. The remaining two-thirds of the structure is given over to an area of 4,800 sq. meters. CUBE's space is exceedingly user friendly. The arena, concert hall, and immediately surrounding space are encompassed by huge movable walls. (They measure 14 meters high by 50 meters wide.) The inside of the arena has walls that can be moved in to divide the space.

An immense door in the back wall of the concert hall stage opens onto the arena area, maximizing the dramatic possibilities for opera and other theatrical presentations that will use the large "back-stage" expanse to enhance their productions.

CUBE (Interior)
The Glass Concert Hall The initial concept of CUBE's Glass Concert Hall is partially the brainchild of the hall's musical director, composer Shigeaki Saegusa. Mr. Saegusa's wish was for a hall with the long reverberation (seven seconds) common in European cathedrals. Architect Horiike's vision was of an auditorium so filled with light that the audience would feel as if they were not inside but rather out in the great outdoors. The city of Shiroishi's mayor asked that all preconceived notions be left behind so that the hall would unlike any that had been built before. To ensure that those of engaged in the project would not be influenced by other structures, we were instructed not to visit any other halls, as this could limit the free-flow of our ideas. On top of all of this, we were specifically charged with achieving the best room acoustics to be found anywhere in Japan! The three gentlemen that we had to answer to were exceedingly clear about how the hall would look: a glass cube, surrounded by glass, where even the seats would be glass (in actuality, acrylic). In this environment, to be told that the acoustics -- while not necessarily having to achieve the seven-second reverberation time -- had to be second to none was truly a difficult assignment.

Reverberation Time
(Upper: without acoustic curtain
Lower: with acoustic curtain )
The Concert Hall's Room Acoustics The planar view of the hall is an ellipse. The glass walls are all perpendicular to the floor. In order to achieve the desired room acoustics, and sound and light deflection, the walls are double-louvered, so that the size and angle of the inner walls could be controlled for the best room acoustics. The ceiling is designed of triangles set at many different angles. As a result, the initial sound reflections encounter an appropriate amount of obstacles and hurdles on their way to reaching the audience. In order to stretch the reverberation time, the seating was left without any covering that could absorb sound. The reverberation achieved is 3.9 seconds/500 Hz when the hall is empty, and 2.2 seconds with the hall full, a difference of 1.7 seconds.

The hall definitely defies what is typical in a civic hall. However, since we were aware that the hall is likely to be used in much the same way as other public halls, we determined that the hall's acoustics should be adaptable to match the variety of uses of the hall. We therefore installed retractable absorption curtains on the upper portions of the side walls. When these curtains are in use, the empty hall's reverberation time is 2.4 seconds/500 Hz, and 1.6 seconds for a full hall. The absorption curtains are designed to be used during rehearsals (to adjust for the large reverberation variance between an empty and full hall) and when the hall is used for a lecture or a performance using electric voice amplification.

The Pipe Organ Pipe organs are the centerpiece of the kind of church music that inspired Mr. Saegusa's desire for long reverberation time. CUBE's pipe organ is the work of Tokugoro Obayashi, and it is a most unique instrument. Not only is it a large instrument, with its own imbedded loudspeaker and 115 stops, but it can be made to play without a performer through the use of a MIDI interface. (The pipe organ can, of course, also be used for live performances.) The hall anticipates that it will only have a limited ability to invite organists to perform at CUBE, so it is also planning some free concerts using the computerized "performer-less" interface.

The Concert Hall's Inauguration and Programs CUBE's Concert Hall inaugural concert, under the production of Mr. Saegusa, is set for June 27 through June 29. In addition, Mr. Saegusa has already committed to organizing a monthly series named "Shigeaki Saegusa's Music University," in which he plans to lead seminars on classical music using the concert hall space.

Now that this unique space has come to fruition, we look forward to CUBE's developing more and more programming to show off its pipe organ and provide an acoustically matched venue for performance of church music.

CUBE's Electrical Acoustic Equipment and Facilities In designing CUBE's electrical acoustic equipment and facilities, there were two areas of overlap between the needs of the concert hall and the needs of the arena, and then there were numerous divergent needs. Let me address the overlapping needs first.

(1) Both the concert hall and the arena required facilities and equipment for public announcements and for speeches using microphones. For this purpose, the loudspeakers we chose are made primarily for the sound registers of the human voice. The subwoofers that are often installed in multi-purpose halls for the reproduction of the lower registers of music have not been installed in CUBE.

(2) In both the concert hall and the arena, most of the loudspeakers are visible to the audience. To minimize the visual impact, all of the loudspeakers have been given a white finish.

Now to take a look at the challenge specific to the concert hall, the major issue was achieving clear voice reproduction despite the hall's long reverberation time. Immediately above the edge of stage (where a proscenium would be), we suspended two clusters of loudspeakers from the ceiling. Each of the clusters has three loudspeakers. Two of the loudspeakers in each cluster face the audience, and the third loudspeaker in each cluster is designed to reproduce the sound for the people on stage. Special efforts were made to ensure that the sound from the clusters did not bounce off the walls, as this would have resulted in a loss of speech clarity for the audience. In particular, we selected EAW 3-way loudspeakers for the four loudspeakers facing the audience, selecting a size that might be considered somewhat large given the overall size of the hall.

In addition to the suspended loudspeaker clusters, six front loudspeakers were installed on stage, to be used in combination with the clusters. As soon as the hall's construction was completed, we installed all of the loudspeakers and tested the clarity. Our tests revealed that we had achieved excellent clarity for speeches even when we did not use the absorption curtains. Thus, we proved to ourselves that by using sufficiently large loudspeakers in sufficient number and set at the appropriate angles, it is possible to achieve clear amplified speech even in a room with a long reverberation time. Since I had been a bit concerned that CUBE might be an acoustical Pandora's Box, I was well relieved to have such a successful outcome.

The challenge of CUBE's arena was the opposite of the concert hall's: the arena has a short reverberation time (2.7 seconds/500 Hz when empty, V=63,500m3), and there is no definite stage location. To accommodate the expected use of the arena's partitions, we suspended 12 loudspeakers from the ceiling throughout the entire arena. We chose EAW 2-way loudspeakers and, in contrast to our selection for the concert hall, the size we selected was rather small given the scale of the arena. We selected small-ish loudspeakers because we wanted to emphasize their directional characteristics. Prior to installation, I was somewhat concerned about whether 12 loudspeakers would be sufficient to, given the distance from the ceiling to the floor of the arena and the total area of the arena floor. But, happily again, our post-installation testing affirmed that this number and size of loudspeakers was sufficient to accomplish our objective of clearly reproduced speech throughout the entire arena.

CUBE is located at 50 Aza-Toribami,Takasu, Shiroishi City, Miyagi Prefecture.
Tel: 81-224-22-1290. Fax: 81-224-22-1289.

Innovations Galore in the U.S. Audio Market

by Katsuji Naniwa

Every year, U.S. professional-quality audio manufacturers gather to exhibit their newest products and systems at the NSCA Show. This year, the NSCA Show was held at the Charlotte, North Carolina Convention Center. Below are my impressions of both the NSCA Show and the acoustical equipment at several sites that I visited while in the United States.

My initial reaction to the NSCA Show was astonishment. I was astonished at the sheer size of the convention center and the number of exhibitors. I was amazed that the world,s largest audio equipment manufacturers and tiny start-ups were rubbing shoulders in tiny exhibition booths, all given equal space. And there was that astronomical number of between 400 and 500 exhibitors! The main hall of the convention center was given over exclusively to visual displays of merchandise and the opportunity to negotiate with exhibitors, while listening demonstration rooms were set off in a separate area. In the demonstration area, it was clear that each participating company had turned up the decibels to demonstrate its equipment to the Show's visitors.

The NSCA Show included an incredible variety of exhibitors. In addition to manufacturers of audio and audio-related equipment, there were exhibitors of all kinds of equipment for installing audio systems, such as connectors, cables, racks, and electrical outlets. There were manufacturers of audio equipment stands and wiring tools, and some of the most innovative products could be found among these manufacturers of audio system peripherals. I can't help remembering the booth that showed a truly unique stone throwing product, using a combination of a slingshot and fishing reel. This product has the intended purpose of assisting in setting a cable. To operate this unforgettable device, a weight attached to the fishing line is cast out to the place where the cable is to be installed. The cable is then tied to the fishing line and reeled in until it is installed in the desired location. If this all seems phantasmagorical, I can at least assure you that this booth provided enjoyable comic relief from my pursuit of exhibits more appropriately related to my professional acoustical interests.

Extremely light loudspeaker
lifted by a finger
One exhibit that caught my interest displayed new ultra-light speakers. Carbon fiber materials was used for these speakers' enclosures and the developer had obviously gone to great pains to successfully deaden the resonance created by using this material for the enclosures. The result was that the company's mid-size box, designed for a 38cm woofer, was light enough that it could be lifted with the pinkie of one hand. While the price tag of this product was not inexpensive, I can certainly see how these ultra-light speakers could benefit the staff of a performing group while on tour, and they might also provide solutions for audio systems that have strict weight limitations. The manufacturer of the ultra-light speakers offered a variety of configurations on a per-order basis, further expanding the possible uses of this new product. Another new product that impressed me was a 3-way speaker system designed for situations of extremely limited space. Instead of employing a horn for the mid-range, it used a cone speaker unit to reduce the overall depth of the system. These kinds of innovations are most welcome by people like myself because they increase my options when planning audio systems to meet the special needs of clients. From a show of over 400 exhibitors, I have singled out only two of the products that caught my eye. But, of course, I left the show with my arms full of brochures and information on many products, audio systems, and devices that I may wish to investigate further at a later date.

In addition to attending the NSCA Show, I took the opportunity to visit several U.S. sites with advanced audio system equipment. Wherever I visited, I was struck by the mixing and matching of various brands of audio equipment. If a piece of equipment was best made by a certain manufacturer, that was the piece of equipment chosen, and the audio components of multiple companies would be connected to achieve a superior and unique audio system. This freedom to mix and match equipment from multiple audio manufacturers is not just the result of a clear demarcation between audio manufacturers and the construction companies responsible for a project. It is also a measure of the respect that Americans have for entrepreneurship, inventors, and the value of recognizing individuals' great ideas and innovations. No wonder that the U.S. environment produces such a large and diverse professional audio equipment marketplace. In my desire to partake of the expertise I witnessed, I recognized that the U.S. audio environment underscores our need for a global perspective, standards, and interfaces to facilitate worldwide access to the myriad audio innovations developed in the United States every day.

Nagata Acoustics News 97-6iNo.114j
Issued : June 25, 1997

Nagata Acoustics Inc.

E-mail: info@nagata.co.jp

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