Quietness, Comfortable Sound and Excellent Acoustics NAGATA ACOUSTICS

News 13-04 (No.304)

Issued : April 25, 2013

[ Japanese Version ]

First Anniversary of Ashibi-no-Kura and Komorebi Hall in Nishikata-cho, Tochigi Pref.

By Dr. Minoru Nagata, Founder of Nagata Acoustics

Ashibi-no-Kura and Komorebi Hall
Ashibi-no-Kura and Komorebi Hall

Elevation and Plan
Fig. 1 Elevation and Plan

In February, 2012, two small private halls opened in Nishikata-cho, Tochigi Pref. on the grounds of residential property owned by Ms. Noriko Nakaarai. For more than 30 years, Ms. Nakaarai has been an educator as well as a professional organist and pianist.

With Nagata Acoustics' help, Ms. Nakaarai renovated two old Japanese-style structures located on her property and turned these spaces into small halls for music performance, practice and instruction. One is Ashibi-no-Kura Hall, a 150-year-old "kura" (a traditional Japanese storehouse) that now has a 6-stop box organ crafted in Holland and seating for up to a 40-person audience. The other structure, Komorebi Hall, was renovated to increase its size and remodel it into a small recital hall with a Yamaha C7 grand piano and seating for a 70-person audience. Together, these spaces comprise Ms. Nakaarai's Concert Hall Nishikata.

Ms. Nakaarai's home is located in an area that is mostly farmland and some 80 km. (50 miles) from Tokyo. However, the Tobu Nikko Train Line runs near the west side of her home and a national highway passes by the east border of her property and the frequency of both trains and trucks passing the vicinity is very high. (This highway follows the same route as a road that was part of Nikko Kaido during Japan's Edo Period.) In addition, helicopters going to and from the Japan Ground Self-Defense Force Kita-Utsunomiya Base can periodically be heard flying overhead. In sum, the ambient environment is not a quiet, pastoral setting.

I explained to her that the anti-vibration and sound isolation measures that we would be able to implement be limited because of the project budget. Ms. Nakaarai understood and accepted this constraint, so we proceeded with developing the acoustical designs for the two spaces. Now that the first year of the halls' operations has passed, I feel reassured that there were no instances of sound isolation issues.

M.A.P. Kenchiku Keikaku served as the project architect and I led the acoustical design work. The elevation and plan views of Ashibi-no-Kura and Komorebi Hall are shown in Fig. 1.

<< Acoustical Design of Ashibi-no-Kura >>


The interior of Ashibi-no-Kura has thick, mud walls with plaster coatings that only minimally absorb low frequency sound and I considered it would be suited to organ music. Our renovation plan kept the original wood floor but, in order to gain as much spatial volume as possible, removed the traditional cupboards and wood balcony.

Ashibi-no-Kura's interior has a total floor area of 25 sq. m. and ceiling height of 5 m. We did not make any changes to the building's existing wooden door or its HVAC equipment.

By the way, the name of this hall refers to the pieris japonica. Ms. Nakaarai has a garden where this plant grows in abundance, with beautiful blooms in the spring.

<< Acoustical Design of Komorebi Hall >>

Komorebi Hall
Komorebi Hall

In Japanese, "komorebi" refers to the the sunlight shifting down through the trees. Komorebi Hall was planned as a recital hall for piano and chamber music and as a studio where Ms. Nakaarai gives piano and traditional children's song lessons. For these objectives we decided to increase the room's available floor space to the maximum extent possible. We widened the room by 4 m., resulting in a total floor area of 60 sq. m. with the ceiling height of 5 m. in this hall.

Before the renovation, this building was just a basic storage structure, so our keynote was on preventing sound from leaking out into the neighborhood. The design we developed added triple layers of 15 mm. gypsum board along both the walls and the ceiling for both the sound isolation and an interior design treatment. Also, we replaced the structures' four windows with double-pane glass in anti-noise frames. For the design of the entrance door to the hall, we took into consideration the need to use this entry to bring pianos in and out of the hall, and set the entryway dimensions at 1.85 m. wide by 1.8 m. high. For sound isolation purposes, we selected double doors of steel and wood.

When the renovation of the building was nearly complete, a piano was installed for an inspection. After playing for a while, Ms. Nakaarai requested that we change the room's reverberation characteristics to decrease the remaining reverberations produced when she played certain musical notes. To adjust the acoustics for this new requirement, we additionally installed 10 sound absorbing panels and thereby controlled the reverberation in the room. The visible side of these sound absorbing panels is 6 mm.-thick MDF board with 9 mm.-diameter perforations at intervals of 30 mm. Behind the fiberboard we placed 15 mm.-thick glass wool. Each board measures 0.9 m. wide by 1.2 m. high. We installed these sound absorbing elements at various locations on three of the hall's walls.

<< Characteristics of the Two Halls >>

Reverberation Time in Ashibi-no-Kura
Fig. 2 Reverberation Time in Ashibi-no-Kura

Reverberation Time in Komorebi Hall
Fig. 3 Reverberation Time in Komorebi Hall

Reverberation Times
The reverberation times for each of the two halls can be seen in Figs. 2 and 3. I listened to a performance in Ashibi-no-Kura and found the reverberations well suited to period instruments and, in particular, the organ installed in the hall.

Komorebi Hall has a flat reverberation characteristic from low octaves through higher ranges. This characteristic makes the room appropriate for the intended piano performances, piano practice and the variety of music instruction classes that Ms. Nakaarai teaches.

Sound Isolation
The original door of Ashibi-no-Kura has a sound isolation performance level of 21 dB (at 500 Hz) and the original windows have sound isolation performance levels of between 25 dB and 32 dB. It would be beneficial if at least the door can be upgraded to one that would provide stronger sound isolation.

In Komorebi Hall, the door's sound isolation performance level measures 43 dB. The windows and walls provide sound isolation performance levels of between 45 and 51 dB. The levels that we achieved enable Ms. Nakaarai to successfully use the hall for performances and classes without sound isolation issues.

HVAC System Noise
When Ashibi-no-Kura's HVAC equipment is run on its low setting, it produces 36 dBA of noise. In Komorebi Hall, the HVAC noise level is 35 dBA. For the professional quality recordings, Ms. Nakaarai deals with its noise by turning off the system.

<< Activities during the Halls' First 13 Months >>

In this locale, nurturing a following for classical music remains difficult. To date, Ms. Nakaarai has held four concerts and has rented the halls to others just twice. In the meantime, Ms. Nakaarai enjoys using both halls for her own organ and piano practice as well as children's choral and piano lessons.

At the outset of this project's planning, Ms. Nakaarai envisioned building a chapel-style "Nishikata Organ Hall" that would seat an audience of 200 people. Eventually, the project came together with the implemented plan of two spaces with a more multi-purpose design. I think this planning evolution bore good results. In the future, I hope that Ms. Nakaarai will focus on improving the access path and the entrance area of the halls, and that these halls will be increasingly used and appreciated as acoustically balanced spaces where Ms. Nakaarai can nurture her musical talent and the talent of her students.

Ms. Nakaarai maintains the website Concert Hall Nishikata with links to her blog and other pages (only in Japanese).

Visitors can access the two halls by taking the Tobu Nikko line to Tobu Kanzaki Station. The halls are a brief six-minute walk from the station at 342-1 Nishikata-cho, Tochigi City. The contact phone number is +81-282-92-2815.

Highlights of the Stage Lighting Designers' Seminar on Latest LED Technology

By Makoto Ino

Various LED Luminaries for Stage Lighting
Various LED Luminaries for Stage Lighting

Lighting Test for the KABUKI Acts
Lighting Test for the KABUKI Acts

On March 26, 2013, at Le Theatre Ginza, I participated in a seminar about the current and future trends in LED lighting for use in professional stage lighting installations. The Japan Association of Lighting Engineers and Designers and the LED Testing Council jointly sponsored the event.

LED (Light Emitting Diode) lights consume a small fraction of the energy required by traditional filament bulb lights. The development of blue diodes led to further development of commercial applications of white LED lights for sale in the general marketplace. Also, the brightness options of LED light products continue to show improvement. As a result of these advancements, LED lighting has experienced a surge in popularity in Japan, where energy efficiency is a high priority. The switch to LEDs for traffic lights, street lights, office lighting and residential lighting is progressing at a fast pace.

However, the specific needs of stage lighting-especially for dramatic theatre-include detailed color variations, strong power and wide angle or targeted coverage. These essential requirements of stage lighting have prevented immediate adoption of LED lighting by the stage lighting community in Japan.

Meanwhile, for popular music concerts and entertainment attractions, moving lights (also known as automated lights or automated luminaries) have become the standard lighting method. These electrically powered fixtures can be programmed for the direction of the beam, its shape, angle, edge, color filters, "gobo" patterns and a range of other features. If a moving light is suspended in advance at a venue, pre-performance lighting preparations and work to determine the settings for various stage sets can all be done in parallel. LED lights, which are more compact than traditional light bulbs and also give off much less heat, have already been easily adapted for use in moving light fixtures. As might be expected, at the March seminar, LED products for moving lights accounted for many of the products introduced to participants. The vendors who introduced products at this seminar are companies based outside Japan.

For the varied color temperatures and spectrum needed by stage lighting, progress continues rapidly in developing and improving RGB+White LEDs and multi-color LEDs. I expect that theatres and halls in Japan will rapidly begin installing LED fixtures, especially for moving lights. Currently, it seems that Japanese lighting manufacturers are behind their international counterparts in promoting this new technology in their products and in responding to requests regarding this new technology from Japanese stage lighting professionals. Local Japanese vendors typically excel in producing high precision "stuff". I look forward to seeing what quintessentially Japanese features local lighting manufacturers and venders will add to their products to make their LED lights for professional stage use ultra-convenient, must-have products.

Highlights from the British Council's Forum on Music Education

By Dr. Keiji Oguchi

Attracted by the event title: "How Orchestras and Concert Halls Partner with Communities-a Forum about Innovations in Music Education Programming", I attended this day of speaker presentations sponsored by the British Council. The event was held in Muza Kawasaki's Assembly Hall. The event program had an ambitious agenda that began with an opening welcome from a representative of the event sponsor followed by reports from participants of the recently completed January 25 to February 4 training trip in the UK for Japanese orchestra, theatre and concert hall personnel. After these presentations, the agenda called for an overview of the London Symphony Orchestra (LSO) "Discovery" education program, discussion time and questions from the audience. However, the reports by the Japanese orchestra, theatre and concert hall personnel who had traveled to the UK ran longer than expected and became most of the event's program. From this I could gather the value of the council's program in the UK and the strong impressions it made on the program participants.

<< The British Council's Training Trip to the UK by Japanese Performing Arts Professionals >>

The forum brochure explained that the council aims to deepen cross-cultural understanding among Japanese and British performing arts organizations by having the Japanese training trip participants visit the UK, observe diverse educational programs and exchange ideas with UK performing arts personnel about strategies and practical implementations for music education. The British Council sponsored this trip in partnership with the BBC Symphony Orchestra and coordinated the timing to overlap with the orchestra's "Total Immersion: Sounds from Japan" week of concerts and lectures. The group from Japan included 5 participants from Japanese professional orchestras and 5 from concert halls and cultural foundations. The selected participants came from 5 Japanese cities.

<< Key Learnings from the UK Training Trip >>

At the forum, each program participant spoke about the UK program from both the objective perspective of what they saw and did, and from their subjective personal impressions and feelings about their experiences. The diverse professional backgrounds and roles of the participants resulted in each report having unique and deeply perceptive content. I was particularly impressed by three observations:

  • In the UK, music education programming involves not only activities inside halls and by orchestras at their regular performance venues, but also proactive outreach activities that bring the wonder of music to people in their community or school settings. Orchestras and halls in the UK began this kind of innovative programming in the 1980s and the UK now has diverse programs suited to the special characteristics of each performing arts organization.
  • The programs in the UK place less emphasis on music appreciation (listening) and more on creativity (music composition). When contemporary music is included in children's music education programs, the program creators find that contemporary music fascinates the children, who come to the music without preconceptions and without prior formal music training.
  • The French word "animateur" means "to bring alive" or "put into action". In the UK, animateurs do not simply organize or lead educational workshops and concerts. They enhance children's performances by becoming participants and collaborators with both performers and audiences to make the concert unfold in a way that children discover the richness of a concert program's content.
    Some days after the British Council Forum event, I attended the LSO concert for Children at Suntory Hall Concert. This concert featured animateur Rachel Leach and gave me the opportunity of experiencing at first-hand the special contribution an animateur can make to a concert for children. The animateur role requires strong multidisciplinary training in musicology and instrument performance training, theatre arts training in acting and directing, and training in psychology as well. Ms. Leach's alma mater, London's Guildhall School of Music and Drama, is a leading conservatory and drama school for producing performers who excel in the animateur role.

<< Long Term Goals of the UK's Music Education >>

Even compared with other European countries, the UK has a long history of pioneering and developing music education. At the British Council's forum event, Eleanor Gussman, head of the LSO's Discovery education program, gave the event's concluding remarks. She spoke of four main goals for music education: (1) Sharing the thrill of music-making with people of all ages; (2) Developing audiences of the future; (3) Investing in the next generation of orchestral players; and (4) LSO musicians: "to put something back and reinvigorate practice".

Ms. Gussman did not mention economics in so many words. But in a world where shifts in politics may affect funding for the performing arts, nurturing children's participation in music performing arts will surely also be beneficial to growing a stable economic base for both children's and adult performing arts programming.

More information about the forum can be found in the council's Facebook page (in Japanese), and video of the forum can be seen at YouTube.

Nagata Acoustics Inc.

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

(LA Office)
2130 Sawtelle Blvd., Suite 308
Los Angeles, CA 90025, U.S.A.
Tel: +1-310-231-7878, Fax: +1-310-231-7816

(Paris Office)
75, avenue Parmentier
75011 Paris, France
Tel: +33 (0)1 40 21 44 25, Fax: +33 (0)1 40 21 24 00

E-mail: info@nagata.co.jp

[ Japanese Version ]