News 16-01 (No.337)
Issued : January 25, 2016
By Akira Ono
Chabohiba Hall Exterior
View of Chabohiba Hall
Interior from the Courtyard
The Chabohiba Tree Preserved at the Project Site
On December 17, 2015, the newly constructed Chabohiba Hall held its opening concert. The new hall is located in the Saiwaicho neighborhood of Tachikawa City, part of Tokyo Metropolitan Area.
Ms. Yoshiko Komine owns the land on which the hall was built and funded the construction of the hall. Architect Satoshi Okada and his firm Satoshi Okada Architects designed the hall. Nihon Kensetsu Co. Ltd. was the project’s general contractor. Nagata Acoustics participated as the acoustical consultant from the beginning of the project’s design phase. Our role included all aspects of acoustical design as well as related on-site management and post-construction evaluation activities.
<< The Hall’s Name and Origins of the Project >>
Chabohiba is a species of Japanese cypress (hinoki) often decoratively pruned in the style known as tama chirashi (“ball scattering”). The tall chabohiba tree shown in the accompanying photo has this kind of pruning. This impressive example of the species has stood on Ms. Komine’s property across many years of history as an integral part of the landscape. Preserving the tree and its prominence were part of the architectural design’s intent and Mr. Okada designed the building so that the tree stands in a courtyard surrounded by the hall’s low-profile structure. Appropriately, the hall bears the name of the tree’s species.
Ms. Komine is a longtime music enthusiast but not herself a performer, humbly saying that she cannot play “even a few bars on the piano as a pastime”. Nevertheless, Ms. Komine wanted to use a corner of this land that has been in her family for generations to build a concert hall that she can—in turn—pass down to her descendants. Chabohiba Hall is the realization of Ms. Komine’s goal for the site.
<< Hall Overview >>
Chabohiba Hall is a flat-floored hall that seats about 100 people. We designed the acoustics primarily for classical music. Our programming brief also included use of the hall for parties, exhibitions and other events suited to a flat-floored venue. We considered all of these uses as we developed the acoustical design.
The hall’s ceiling is a gently sloping quadratic surface 6 m. (20 ft) above the floor. The floor’s footprint is nearly rectangular in shape, measuring 16 m. (52 ft) wide and 9 m. (29 ft) deep. When the stackable seating is configured for concert hall use, the chairs are set up facing one of the 9 m. walls or in a semicircle around the performers.
The side of the hall that faces the courtyard garden has window coverings reminiscent of Japanese yukimi shoji, with sections of the window coverings being independently retractable to make the garden visible from inside the hall. When the garden is in view, the white gravel that frames the inner perimeter of the courtyard softly reflects light into the hall interior. At artfully placed locations on the white gravel, a large rock and a ceramic jar that have been on the property since as far back as anyone knows decorate the garden courtyard like art objects.
The dividing wall between the building’s foyer and the hall is formed of panels that rotate vertically on their axes. As can be seen in the accompanying photo, when the panels are rotated open, the garden and pond come into view, as well as the monument-like, tall Chabohiba tree.
View of Hall Interior from Hall Balcony
View of Hall Interior from Back Row of Seating
View of the Courtyard from Inside the Hall
<< Concrete and Wood Wool Hall Interior >>
The hall interior features exposed concrete and wood wool (excelsior) in a sleek design. Wood wool covers large portions of the front and side walls. Wood wool is a sound absorbing material and if it were installed in the concert hall as is, the hall would have had too much sound absorbing surface area. To make this material appropriate to the space and acoustics, we asked the installer to use the strongest possible high-pressure spray application of the material. Responding to our request, the installer prepared a number of samples in an outdoor location until finding the point at which the material would slump instead of staying in place.
The wood wool surface visually satisfied the architect’s interior design objectives. From Nagata Acoustics’ perspective, in addition to changing the material’s sound absorption characteristic, we needed to address another acoustical requirement for the material to work well with our room acoustics design. This requirement was the addition of fine horizontal ribbing on the surface of the material to increase the walls’ sound dispersion characteristic. As part of our room acoustics design we also installed sound-reflecting eaves at a height 5 m. (16 ft) above the floor, specifically to obtain sound reflections during musical performances.
A balcony gallery extends along the side wall above the hall’s vertically rotating doors. This space is not intended for audience seating but instead for lighting, photography and similar technical purposes.
<< Chabohiba Hall Operational Start and Opening Concert >>
When an individual patron embarks on operating a hall—even if the size of the hall is just 100 seats—success depends on having the proper knowledge and experience combined with professionals who can make swift and appropriate decisions and take appropriate actions in various situations. Ms. Komine asked us to introduce her to someone who could fill this professional role. Nagata Acoustics didn’t immediately have the right person to recommend so we consulted with Mr. Toshiya Kusaka, theatrical consultant and owner of Arts Space Factory. (An article about a talk by Mr. Kusaka can be found in our May, 2011 newsletter.) Mr. Kusaka introduced us to the Japanese non-profit organization Art Network Japan’s Board Chairperson, Ms. Naoko Hasuike.
Serendipitously, at the time we introduced Ms. Komine to Art Network Japan (ANJ), ANJ was planning its Tachikawa Culture Factory initiative and had ties with a number of people in the arts in the Tachikawa area. A relationship between ANJ and Chabohiba Hall was established and ANJ stepped into the professional role quickly. ANJ made all of the arrangements for the hall’s opening, including scheduling, preparing printed materials, setting up the hall’s online presence with a website at http://chabohiba.jp and negotiating performances by musicians.
For the hall’s opening concert, Ms. Komine’s friend and pianist Yuko Hisamoto and tenor Kei Fukui performed. Before the opening concert, both Ms. Hisamoto and Mr. Fukui visited the new hall more than once to prepare for the concert. In particular, as soon as the Böesdendorfer Model 225 piano arrived in the hall, Ms. Hisamoto enthusiastically came to the hall and engrossed herself in practice. Mr. Fukui also diligently familiarized himself with the new hall’s acoustics. Their efforts paid off handsomely in a concert that showcased this small music venue’s sound and delivered stirring performances.
Chabohiba Hall has much potential and its successful opening concert gives it an excellent start. I look forward to more satisfying concerts and events in this space.
A Second Visit to Bregenz Festival after 24 Years
By Dr. Keiji Oguchi
Turandot Curtain Call
Daytime Photo of Bergenz Floating Stage Theatre
Loudspeaker Belts and a view of the Stage
on the Lake and Grandstand Audience Seating
Bregenz Open Acoustics System
(Image Courtesy of Otaritec Corporation)
In the summer of 2015 I attended the Bregenz Festival in Bregenz, Austria and enjoyed a performance of Puccini’s Turandot. It was my first return visit to the festival since 1991. That summer I attended Bizet’s Carmen. In the summer of 1992 some of my Nagata Acoustics colleagues attended the festival, but I did not join them that year.
On my arrival at the festival venue last summer I immediately noticed the expanded grandstand seating and the updated sound system with coverage for the entire audience. Bregenz is located on the shores of Lake Constance at the westernmost tip of Austria, sandwiched between Germany to the north and Switzerland to the south. My arrival route to Bregenz took me along the shores of the lake and I saw the increased size of the festival audience seating grandstands as I approached the Bregenz Festival venue.
The seating capacity has been increased from 5,000 seats to 7,000 seats. Also, the venue’s recently introduced loudspeaker system has speakers visibly attached to rails along the outer walls of the amphitheatre, forming a belt around the outer perimeter of the audience seating. Seen from the distance, the audience seating looks as if someone tied a ribbon around it.
<< A Comparison of the 1991 and 2015 Bregenz Festival Sound Systems >>
The Bregenz Festival opera venue—where the operas are performed on a floating stage built at Lake Constance’s edge—is famous for having fine quality sound amplification with impeccable source image localization. When I attended the festival in 1991, the festival created the source image localization using a Delta Stereophony System (DSS) which relies on the Haas effect (also known as the precedence effect or the law of the first wavefront). In the Bregenz Festival DSS system, microphones were placed near the opera singers and connected to two sets of loudspeakers. One set of speakers were placed near the singers. These speakers directly supplied sound components into the venue space. The other set of speakers supplied sound into the space with appropriate delays as well as amplification. Through this method, the source image localization was preserved while increasing the sound volume. In 1991, other than the speakers stacked on stage lighting towers at the two sides of the audience seating, there were no speakers visible at all in the audience grandstands.
The loudspeaker system at last summer’s festival is a recently developed and installed sound system named Bregenz Open Acoustics (BOA). BOA was developed for Bregenz by Fraunhofer Institute for Digital Media Technology in collaboration with Lawo AG, a company that is well-known and respected around the world for its professional broadcast production, video and sound system equipment. The BOA system is based on wave field synthesize technology by IOSONO (now part of Barco Audio Technologies). IOSONO’s technology relies on the Huygens-Fresnel principle to reproduce sound wave fields.
According to information I obtained from Lawo AG’s Japan sales partner, Otaritec Corporation, the BOA system combines the amplification methodology of typical stage speaker amplification and IOSONO wave field synthesize technology to develop an amplification system that delivers enhanced presence. During the daytime I was able to walk freely in the seating grandstands and to see loudspeakers installed hidden among the venue’s stage.
<< The 1991 and 2015 Acoustics and the Configuration of Orchestra and Chorus >>
I remember that the soloists’ portions of the performance sounded appropriately localized and had sufficient sound volume when I attended the 1991 Carmen performance. In 2015, in addition to the fine localization and amplification, I sensed a reverberance despite being in an open-air venue.
In 1991, the orchestra and chorus performed from a pit under the stage. Their performances were picked up by microphones and amplified from loudspeakers located on the stage. For the 2015 Turandot performance, the orchestra and chorus performed on the indoor stage of the Festival Theatre Large Hall (1,000-seat capacity), built behind the grandstands, and the performances were transmitted to the stage and amplified to the audience from the stage loudspeakers. All of the sound is converted to digital signals and delays would normally be expected to occur. How the adjustments are made is an aspect of the system that piques my interest.
<< An Experience that Made Me Want to Return Again >>
Even though the Turandot performance began at 9:00 p.m., on this summer evening the sky was not yet totally dark. Audience patrons arrived by boat from both Lake Constance’s German and Swiss sides to the festival’s pier beside the stage. Against the darkening sky, this prelude to the opera performance created a most distinctive atmosphere.
Now that the orchestra and chorus have been relocated to the inside facility, the festival has room for larger scale productions. The acoustics and sense of presence at Bregenz Festival make this an event I want to experience again.
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
1990 S. Bundy Drive, Suite 795
Los Angeles, CA 90025
Tel: +1-310-231-7878, Fax: +1-310-231-7816
75, avenue Parmentier
Tel: +33 (0)1 40 21 44 25, Fax: +33 (0)1 40 21 24 00