News 15-04 (No.328)
Issued : April 25, 2015
Kawagoe Bible Church Dedicates New Church Building
By Fumiaki Sakamaki
Exterior of New Church Building
（Photo: Hiroshi Tanigawa）
（Photo: Hiroshi Tanigawa）
Altar’s High-placed Windows
（Photo: Hiroshi Tanigawa）
（Photo: Hiroshi Tanigawa）
On March 14, 2015, Kawagoe Bible Church held a dedication ceremony for its new home in Kawagoe City, Saitama Prefecture. Kawagoe Bible Church was founded in 1962 as a Protestant church. Initially, the congregation used the name Kawagoe Bible Center, changing it to the current name in 1968. In 1985, the congregation dedicated their first church building and for 30 years thereafter they worshiped there and maintained it with care and attention. As the old building aged, the congregation realized it was time for a new building. The new church’s planning and construction continued for 10 years, completing at last in December 2014.
Pelican Architectural Design Studio designed the new church building. Kitano Construction Corp. served as the general contractor.
The new church building is a 2-story structure located in close proximity to the original church building, on the opposite side of the same street. The new church has offices and a social hall on the ground floor and the sanctuary on the second floor.
The new church sanctuary has 234 seats. The pipe organ of the original church, a 6-stop instrument made by Köberle Orgelbaumeister of Germany, is installed at the right side of the new sanctuary’s altar (i.e., the right side when facing the altar from the congregational seating). In the predominantly white interior of the sanctuary, light from the room’s high-placed windows creates a variety of moods depending on the time of day.
<< Room Acoustics of the New Church Sanctuary >>
We designed the room acoustics of the sanctuary for the requirements of this Protestant congregration.Specifically, the sermon must be heard with clarity and the room should be suited for music performances including the pipe organ music, choir's choral singing and other instrumental performances. So we planned for a room with a rather long reverberation time with adequate sound amplification system for sermons.
The sanctuary dimensions measure 12 m. (39 ft) wide and 17 m. (56 ft) deep, with a 5.5 m. (18 ft)-high ceiling. The new sanctuary’s ceiling height exceeds that of the original church sanctuary by 1 or 2 m. (3 – 7 ft).
As can be seen in the accompanying photo of the new church building’s exterior, the wall behind the sanctuary altar appears to have a concave shape. However, to prevent the undesirable acoustical phenomonen of sound focusing, we made every effort to minimize the concave lines of this interior wall. We worked with the architect to design this element so that while it may appear to be concave, it is in fact formed by combining multiple straight-line surfaces.
The sanctuary’s ceiling is mostly parallel to the floor. However, keeping in mind that the front of the sanctuary will most likely be the location used as the performers’ stage for instrumental performances, we gave the ceiling a bit of a convex angle above the altar area. During instrumental performances this design element will prevent flutter echoes that might otherwise be generated if the ceiling and floor were totally parallel.
In selecting materials for the sanctuary interior, we limited the use of sound absorbing surfaces as much as possible, installing some glass wool on the rear wall and acoustic tile around the perimeter of the ceiling. The materials used for all other surfaces in the room are sound-reflecting. Based on measurements we took in the completed sanctuary, with the seating installed the room has a reverberation time of 2 seconds (at 500 Hz, calculated value based on field measurement in the completed empty room). When people fill the seats the reverberation time will be reduced, but we nevertheless achieved the relatively long reverberation time that we set as our goal for the sanctuary’s room acoustic design.
For the sound amplification system, we installed loudspeakers in the ceiling and a digital processor output system to enable adjustment of the sound quality. This setup achieves clear sound amplification in this room regardless of the room’s relatively long reverberation characteristic.
<< Dedication Ceremony >>
（Photo: Hiroshi Tanigawa）
At the March 14 dedication ceremony for the new church, the congregation invited everyone connected with the project. In addition to prayers said in the new sanctuary, church representatives delivered a progress report on the construction.
The event welcomed a special guest—the son of the church’s very first minister attended from the United States. In addition to offering words of congratulation and celebration, he shared memories of his childhood growing up in Kawagoe, filling some in the audience with nostalgia and adding to the warm and embracing atmosphere that pervaded the event.
The dedication event also included choral singing by the church choir, a pipe organ performance and a piano and violin duet. I was pleased to have this opportunity to hear the sanctuary’s acoustics and to be able to confirm with my own ears the beautiful sound produced in this new space. Of course, for me, one of the best parts of attending the event was hearing the positive words about the sanctuary’s acoustics expressed by members of the congregation and to see their happiness with the project’s results.
<< Upcoming Concert Schedule >>
For the months of April, May and June, the church has scheduled a Spring Concert Series of three concerts. One will be a pipe organ concert, one a marimba and violin performance and one a concert by a string quartet.
To this new small venue that will be used both for classical music concerts and as the house of worship for a congregation that will tend it with loving care, I wish many years of use that brings joy and fulfillment to all who come through its doors.
The hall also opened without any acoustical fine tuning and the inaugural night’s concert began a heavily booked schedule of concerts in the venue. As a result, completion of construction and acoustical fine tuning could only proceed intermittently when the hall’s schedule had a brief lull in its use. In particular, when I heard the orchestra rehearse for the first time in the empty hall, it was obvious that the hall has too much reverberant and that this needs adjustment. Happily, however, during concerts with a full audience the acoustics’ rich reverberations and the hall’s good clarity of sound create an enjoyable concert experience. Given the unfortunate situation of having to open the hall without a period of acoustical fine tuning, I breathed a sigh of relief at my first impressions of this new hall’s acoustics.
Tokyo Keizai University Opens “Shin-Issou” (Forward) Hall in Memory of Founder Baron Okura
By Chiaki Ishiwata
Okura Kihachiro Memorial Forward Hall Interior
Tokyo Keizai University completed the renovation of its old library building, repurposing the structure for a new 325-seat hall. Architect Azusa Kito designed the original library building, which completed in 1968 and won the 20th Architectural Institute of Japan Prize. The new hall retains the exterior of the award-winning structure.
Forward Hall officially bears the name of the school’s founder, Baron Kihachiro Okura, as well as the inspirational motto of “Forward Forever” (shin-issou) that Baron Okura advocated as an educational principle when he founded the university. (In Japanese, the word order and official name is “Okura Kihachiro Shin-Issou-kan”.)
<< A Building Design That Incorporates the Natural Musashino Plateau Vertical Drop >>
Tokyo Keizai University is located in Kokubunji City, an area that is part of the greater Tokyo Metropolis and west of the part of Tokyo familiar to most overseas visitors to Japan. Geologically, Kokubunji City includes a raised, flat expanse of land known as Musashino Plateau that has rich greenery and some steep vertical drop-offs of land. The vertical drop from the plateau transverses Tokyo Keizai University’s campus. The old library building was built at the edge of the drop-off and full use of the land’s natural variation was taken into account in the building’s architectural design.
At the entrance side of the building the structure appears to have just one level, but when seen from the opposite side of the building, it’s obvious that the building has 3 levels. Windows that face the Musashino Plateau offer beautiful views of the plateau’s trees and other flora.
In 2013, Tokyo Keizai University completed the building of a new library (designed by the architectural firm AXS Satow, Inc.). The university decided to preserve and repurpose the old library building and selected AXS Satow to design the remodel. Nagata Acoustics joined the project and provided acoustical consulting services.
<< Glass Walls and Sound Isolation >>
The remodel design located Forward Hall on the building’s entrance level by adding partitions to the space that was originally a glass-surrounded reading room. Programming for the hall project indicated that the main uses of Forward Hall will be school ceremonies and lectures. The architect wanted to retain the beautiful, green outdoor vistas of the original space and planned to use glass partitions for the hall.
Two layers of glass between outdoors and the hall
To achieve effective sound isolation between the hall and the outdoors, we worked with the architectural firm and their plan to use clear glass surfaces. In addition to the layer of glass that forms the skin of the building, the design added another layer of glass installed with an appropriate amount of air space between the two glass surfaces. As a result, the two layers of glass achieve the the equivalent sound isolation of one layer of concrete.
For sound isolation between the hall and the lobby, the university decided to manage the need for sound isolation between these two spaces by situationally controlling the flow and activity of people in the lobby. Based on this decision, the project proceeded with implementing the architect’s design of a single glass layer between the lobby and the hall. The entrance doorways between the hall and the lobby each have a single set of entrance doors with sound-isolating gaskets.
For sound absorption in the lobby, we installed wall-to-wall carpet on the floor and acoustic tile on the ceiling. Also, for the sound insulation layer of glass between the lobby and the hall, we specified 12+12t laminated glass material. Through these measures we created a sound isolation performance level that allows people in the lobby to enjoy relatively soft-spoken conversations (especially in parts of the lobby that are not in the immediate vicinity of the hall entrance doors) without negatively impacting events taking place in the hall.
<< Forward Hall’s Acoustics >>
With sound amplication being the primary acoustic functionality required in Forward Hall, our acoustical goal focused on achieving short and natural sound reverberations. Given the room’s low, 4 m. (13 ft) ceiling and resulting modest overall spatial volume, we fundamentally achieved Forward Hall’s sound-absorbing design by specifying the use of carpeting on the floor and semi-upholstered, fixed theatre seating for the audience seating.
While the hall’s sound absorption design was readily accomplished, preventing undesirable sound phenomena required more attention because of the hall’s glass walls. We were concerned that reflections from the room’s rear glass walls might generate long path echoes and we also needed to prevent reflections from the stage-rear glass wall from being picked up by the hall’s microphone and impairing the clarity of amplified sound.
Because some events would require a way to block outdoor light, we devised a solution that works well for this situation by installing retractable curtains with both light-blocking and sound absorbing properties. We located these curtains in front of all the hall’s glass walls, including the glass wall at the rear of the stage and the walls at the back and sides of the hall. In addition to this mitigation mechanism, we pursued a number of other strategies that allow the curtains to be kept open most of the time. Specifically, instead of placing the loudspeakers at the sides of the stage facing the audience, we installed the loudspeakers in the ceiling, dispersing them througout the hall. This design reduces the amount of sound that travels toward the hall’s glass surfaces.
Angled Placement of the Hall’s Glass Panels
Also, as a strategy to prevent long path echoes, we angled some of the floor-to-ceiling panes so that the walls have slight “folds” along their surfaces instead of being perfectly flat. This treatment mitigates the creation of long path sounds that would otherwise return to the stage as strong sound reflections. When we tested the hall’s amplified acoustics at the completion of construction, we confirmed that in this rather compact room, where the seating farthest from the stage is at a distance of just 15 m. (49 ft), the hall’s acoustics perform satisfactorily for ceremonies and similar events without deploying any of the curtains.
For lectures and to optimally enhance the quality and clarity of amplified sound of all events in this hall, deploying the curtain at the rear of the stage to cover the stage-rear glass surface makes a significant difference, and if the curtains in front of the glass walls at the rear of the hall are also deployed, the clarity of the amplified sound is further enhanced. We reported all of our findings to the client so that they can make informed choices that suit the various events and lectures that will take place in the hall.
The Forward Hall project completed last winter and is ready for the new Japanese school year that began in April. I can’t help but wonder how students will focus on the lectures in Forward Hall with the lure of springtime visible on all sides, but I’m sure that the university and the students will make abundant use of this new hall that takes full advantage of the surrounding scenery.
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