Acoustic Design of the Ishibashi Cultural Center

Acoustic design of the Ishibashi Cultural Center 

             – on the occasion of its 50th anniversary

 

Dreamlike technical collaboration

 

It was the autumn in 1961, the season of beautiful red leaves, when Dr. Kiyonori Kikutake, head of Kikutake Architects, visited NHK Technical Research Laboratories. The purpose of his visit was to ask for a technical collaboration in the acoustical design of a hall to be utilized only for music, which Mr. Shojiro Ishibashi, the founder of the Bridgestone Tire Co., Ltd., had been wishing for years to construct in Nonakamachi, Kurume City.

 

Dr. Kikutake asked us to utilize our experiences and know-hows which our Acoustical Department obtained from designing acoustics for Beethoven Hall of Musashino Academia Musicae and Tokyo Bunka Kaikan (Tokyo Metropolitan Festival Hall).

 

We promised him to give all our best supports gladly with the whole Acoustical Department’s expertise, because it was like a dream for us, engaged in architectural acoustic research, to have a chance to participate in such a project.

 

 

Leave it to you

 

The person who had received the request from Dr. Kikutake was Dr. Yasuo Makita, manager of Acoustical Department, later a professor at Kyushu Institute of Design. He was a specialist in the field of architectural acoustics, and had promoted acoustical research and design of the above mentioned music halls. He decided to make essential cross-sectional drawings for the new hall himself in his free moments from manager’s work, and to leave the rest, from making a basic plan to bringing it to completion, to me, sub-manager of the Department.

 

I presume the assignment had been decided in consideration of a background that Kurume City was my hometown, and the promoter of the project was Mr. Kanichiro Ishibashi (President of Bridgestone Corporation at that time). He was the son of the client Mr. Shojiro Ishibashi and was one year ahead of me in Meizen Junior High School. Dr. Makita must have thought that our personal connection would be good for the construction to be proceeded smoothly.

 

Three persons, acting client Mr. Kanichiro Ishibashi, Dr. Kiyonori Kikutake in charge of total construction and me as  architectural acoustic designer, started the construction of the hall.

 

 

Shared principle

 

Client Mr. Shojiro Ishibashi’s request was that the hall should be a one-story structure having 1,200 seats at a maximum and a spacious orchestra pit. With his request as a starting point, we expressed many ideas from our standpoints, and those ideas were summarized into two items.

 

For the item “excellent sound to all audience seats,” we had to set the hall’s reverberation time 20% longer than that of a conventional multi-purpose hall. In order to average primary reflective sound reaching to audience seats, sound reflecting boards on the ceiling had to be properly arranged, and the sloping floor angle of rearward seats area had to be devised attentively.

 

For the item “easiness to play music,” we had to design the ceiling and surrounding walls of the stage to have unbalanced shapes, and the distance between those surfaces had to be set large enough so as to make reflection sound not recognized as an echo.

We started the construction design based on the two items, and that caused the budget increase gradually. The client had to suffer from rising costs over and over again.

 

 

Easier said than done

 

Although to make sound sonorous seems to be a pleasing thing to do when you just hear it, we had to face difficult problems more than we had expected when we started working actually in accordance with drawings for design.

 

Good reflecting boards made unexpected and unnecessary noises when the wall construction had been clumsily done. It took considerable long time to fix boards conforming to the drawings by adjusting them delicately. We had to face so many challenges and difficulties.

 

Because of walls that reflected sound sonorously, it was very difficult to quickly attenuate noises caused by machine vibrations or human movement inside the hall. I did pay much attention where and how to put absorbing materials, which were reduced in quantity for the purpose of obtaining good sonorous sound, to suitable places in order to decrease noises effectively. The more I went to the construction site, the more difficulties I found.

 

 

Sounds good?

 

When the final stage of construction was approaching, contrary to be pleased with the completion of construction, I firstly worried whether the hall would provide sonorous sound as designed, and musical instrument playing sound would be clear, not blur. A few days before the completion, we measured the acoustics of the hall in the midnight and succeeded in getting predicted physical quantities such as reverberation time data, etc. However, I was still anxious about how it would be in a real concert, so that for a verification of actual sound hearing, I asked my friends to bring in and play their instruments in the new hall.

 

On May 3, 1963, the completion ceremony was held and the hall was opened with a performance of Swan Lake of Tchaikovsky by the Kyushu Symphony Orchestra. After the performance, I felt greatly relieved to hear reports on it mentioning that the acoustics of the hall was excellent.

 

 

We did it!

 

We had such a good opportunity to design a hall only for music, and succeeded in obtaining good results just as we had been looking for. We were surprised to be well appraised more than we had expected. We, three promoters, shared a sense of accomplishment and felt a great weight had been removed off our minds. Through communications lasted for two years and more, we had come to call each other with our first names, such as Kanichiro-san and Kiyonori-san. That was a big fruit gained from the project. But, I regret to say that my two friends had passed away and cannot be present at this memorial celebration. I feel so lonely and cheerless. However, the hall itself having a history of fifty years has now improved itself with age. The construction and internal materials have been fitting in well with lots of music played there. From now on, this hall will continue giving exquisite sounds with refined taste to us, music lovers, as a well-aged music hall.