Title means "Quietness", "Comfortable Sound" and "Excellent Acoustics"
Nagata Acoustics News 98-8iNo.128j
Issued : August 25, 1998
Evaluating the Concert Hall Stage
by Keiji Oguchi
Objective evaluation of concert hall stages may be a somewhat Sisyphean task. Every stage quickly earns a reputation from the performers who use it, and their first-hand evaluations are often a function, at least in part, of their familiarity with that stage. Frequently, performers complain about the stage of a new hall, claiming that it is difficult to play. But as time passes, these complaints tend to disappear.
In our own experience, when Suntory Hall first opened, several of Tokyo's orchestras (which number more than ten) participated in the opening series of concerts, along with numerous ensembles and individual performers from around the world. At the time, the Tokyo orchestras, in particular, raised their voices in virtual unison to complain that they had difficulty hearing one another on stage. They blamed the hall's stage with impeding their ability to perform in tutti, to achieve the desired ensemble sound essential to a successful orchestral performance. Prior to the opening of Suntory Hall, most of Tokyo's orchestras held their subscription concerts at Tokyo Bunka Kaikan, in Ueno Park. Tokyo Bunka Kaikan's configuration is of the end-stage type, and the ceiling does not rise very high above the stage. By contrast, Suntory Hall is an arena-shaped hall and has a ceiling that soars at a pronounced height above the stage. Given the difference in the configurations of these two halls, the acoustical conditions on stage are naturally very different. It was therefore equally natural that Tokyo's orchestras would initially complain as they did.
After several years of performances at Suntory Hall, comments about the hall's stage have changed. Tokyo's orchestras became accustomed to the stage's acoustics and the critics began to write about performances in which the orchestras made valuable use of the hall's acoustical characteristics. However, if we ask whether this means that any acoustical situation can be dealt with simply by biding our time while the performers become accustomed to the hall's particular characteristics, unfortunately the answer is not always yes. Certain characteristics are absolutely critical to the viability of a concert hall stage. In this article, I will focus on large halls and some of the stage characteristics that are essential to allow orchestras to perform successfully before such large audiences.
<< The Significance of Stage Width and Depth >>
Table 1 lists representative concert halls and the size of their stages. The first set of measurements in this table that I wish to highlight is the surface area of different halls. The stages of Vienna's Musikverein and Boston's Symphony Hall are less than 200m2, while more recent and contemporary halls have stages that exceed 200m2 of surface area. When orchestras perform compositions from the late romantic period they sometimes require as much as six rows of seating for string players on both the left and right sides of the conductor. This translates to a requirement of 18-to-20m width. Both the Musikverein and Boston Symphony Hall can accommodate an 18-to-20m span.
Table 1 Stage dimensions of large concert hall
|Name||Capacity||Stage Area(m2)||Stage Width(m)||Stage Depth(m)||Stage Height(m)||Ensemble Reflector|
|Boston Symphony Hall||2,625||152||18||10||12.5||Non|
|Munich Philharmony||2,387||230||23.6||14.2||19||Suspended Panel|
|Berlin Philharmony||2,335||172||18.8||13.2||19||Suspended Panel|
|Tokyo Bunka Kaikan||2,327||241||21.7||16||11||Non|
|Tokyo Metropolitan Art Space||2,017||230||20||13.5||19||Canopy|
|Sapporo Concert Hall||2,008||237||22.6||13.5||22||Suspended Panel|
|Suntory Hall, Tokyo||2,006||250||22||12.5||17.5||Suspended Panel|
|Kyoto Concert Hall||1,833||234||21||13||16||Non|
|Sumida Triphony Hall||1,801||260||19.7||13.4||15||Suspended Panel|
However, when we look at how hall stages accommodate depth requirements for seating orchestras, the Musikverein and Boston Symphony Hall are strikingly different from the representative halls built thereafter. An orchestra may require three rows of string players, behind whom sit three rows of winds, behind whom the orchestra wants to place the percussion section. This requires approximately 12m of space from the front to the back of the stage. If we wish to make room for soloists or a chorus, or enable a piano to be brought from the wings without disturbing the seating arrangement, further depth is required. The Musikverein accommodates ensembles that require such depth by extending the stage into the audience, removing several rows of audience seating in the process. In addition, in this venerable hall, bringing a grand piano to the stage when it is set for a full complement of orchestral players is a most cumbersome affair. The legs of the piano must be removed and the piano transported in pieces to the stage. I remember watching with amazement as a grand piano was brought onto the Musikverein stage in this way and wondering if such jostling of the piano adversely affects its tuning.
Though a good ensemble would be difficult to make on a large stage fairly over 18-to-20m in width and 12m in depth, caution should be given to the placement of the orchestra and its relationship to protrusions and other acoustics-affecting conditions in the area near the stage. Many shoebox configuration halls have a balcony around its perimeter. This balcony overhangs the ends of the stage in some cases. The affect of this design is to improve the sound reflections back to the players from the area where the wall meets the corner, but a kind of "booming" distortion is also created if the contrabass and/or timpani players are placed under the balcony overhangs. To control this, it is important to carefully gauge and design the height and depth of such balcony overhangs.
<< The Significance of Ceiling Height >>
Next, let's consider the differences in ceiling heights shown in Table 1. When the above-stage ceiling height of a hall exceeds about 16m, invariably the hall employs some kind of reflection panels to enhance its acoustics. While the Leipzig Gewandhaus has an arena configuration, the above-stage ceiling height has been restrained through clever design planning. At the Munich Philharmony, the transparent, cloud-like reflection panels that are in place today were added several years after the hall's opening because of requests for their installation from the Munich Philharmonic Orchestra, which uses the hall as its home base. At Suntory Hall, the same kind of suspended reflection panels were installed as part of the hall's original acoustical design. The Japan Philharmonic Orchestra, which now performs its regular subscription concerts at Suntory Hall, adjusts the overhead reflection panels to the highest height setting possible whenever it uses the hall. Determining this orchestra's preference for the best height of the panels was achieved by experimenting with various combinations of reflection panel settings and settings of the electrically-adjustable, built-in stage floor risers for several times.
<< The Use of Risers >>
In discussing the arrangement of orchestral players' seating, I will limit my discussion here to the importance of stage risers. When Nagata Acoustics designed the stage acoustics for Suntory Hall, we adopted the Berlin Philharmony as our model, and implemented electrically-controlled built-in risers throughout the stage floor, including the areas that string sections occupy. The risers enable orchestras to create seating arrangements for their players that are much more three dimensional in both appearance and reality than was possible in older Tokyo halls.
The advent of freely-adjustable risers to the Tokyo classical music scene added a new element to the issues involved in evaluating Suntory Hall's stage and, ultimately, the performances held in the new hall. The process of discovering the best riser settings for various orchestral configurations and performances required the sometimes pains taking process of trial and error, and the patience and cooperation of an orchestra's members in testing the various riser options. After pursing the best settings for a period of time, certain general characteristics of using the risers came to light.
The effects of using risers for the orchestra's string sections increases the richness and depth of the strings' sound. The music created by the string sections reaches the audience with strength and clarity. However, this phenomenon means that if the string players are not in sync with one another, their lack of tutti will not be camouflaged from the audience. In addition, as I mentioned at the outset of this article, if the use of risers is new to the players, they will initially complain that they cannot hear one another. Since this perception can only be remedied by repeated exposure to the same stage conditions, I think it may be difficult for visiting orchestras to find value in trying to use the risers of a hall they are visiting for just a few concerts, if they are unaccustomed to a similar setup in their home hall. On the other hand, if an orchestra uses a hall equipped with risers, such as Suntory Hall, for its regular subscription concerts, consistent use of the risers while performing in the hall on a regular basis proves very effective. Several orchestras that use Suntory Hall regularly are very positive and proactive about using the stage's risers. Likewise, at halls in Kyoto and Sapporo, where it was known from the halls' planning stages which orchestra would use each hall as its home base, we strongly encouraged the halls' decision-makers to equip the stages with risers. For these projects, Nagata Acoustics used both explanations and mock-ups for rehearsal in our presentations to provide convincing arguments concerning this valuable stage enhancement.
<< In Summary >>
In the above paragraphs I have touched on several important factors in evaluating the acoustics of a concert hall stage. The dimensions of width and depth, protruding balconies near the stage, and riser enhancements play critical acoustical roles. Of course, there are many other important factors, such as the materials used to construct the stage, the framework structure beneath the stage, and the tuning apparatus around the stage which also affect a stage's acoustics in significant ways. I will look forward to another opportunity when I may present some of my findings and thoughts on these and other considerations in evaluating concert hall stage acoustics.
Renovation of Hatamachi Joho Bunka Center's Act Hall in Nagano Pref.
by Dr. Minoru Nagata
Hatamachi is a town in Nagano Prefecture, the same prefecture where the 1998 Winter Olympics were held. Hatamachi rests nestled along the Azusa River in the mountains west of Matsumoto City, and in centuries past was an important crossroads for agricultural production transported from Nagano Prefecture's Shinshu region to the more mountainous Hida region further west. Today, Hatamachi is perhaps best known within Japan for its delicious watermelon crops.
Travelers can reach Hatamachi by taking the Matsumoto Railroad to the station named Hatamachi, which is two stops before the end of the line. This is the same line that vacationers use to reach the elite wooded retreat villas of Kamikochi.
Hatamachi Joho Bunka Center is a short, 5-minute walk from Hatamachi Station. The center houses a library, Hi-vision-equipped theater, performance practice rooms, the 260-seat Act Hall, and a fourth floor observation deck overlooking the scenic mountain landscape of the area.
My association with Hatamachi and the Joho Bunka Center began in October 1997 when I met Mrs. Hiroko Furuhata -- a Hatamachi resident -- at a social event following a concert. When I met Mrs. Furuhata, I already knew that somewhere in the vicinity of Matsumoto City a hall had procured a fine Bosendorfer piano for use in its facility. On that October evening, Mrs. Furuhata told me that the hall with this distinguished piano is Hatamachi's Act Hall. Mrs. Furuhata also shared with me her cherished memory of a particular piano recital in which the Bosendorfer was played, and her participation in the planning for this event.
The memorable concert was in the summer of 1996. Mrs. Furuhata rallied a group of volunteers to plan a piano recital by Japan's Koichi Yasui. The organizers went to great lengths to ensure that everything was planned perfectly for this concert, even hiring Japan's premier piano tuner, Seiji Inoue, to travel to the little town of Hatamachi to tune the Bosendorfer for the performance. (Mr. Inoue is well known and beloved by Japanese pianists and international pianists who visit Japan, and he is considered the most skilled of all Japanese piano tuners.) Sadly, Mrs. Furuhata informed me, despite all of her extensive preparations, the sound produced during this concert had not met her expectations. Mrs. Furuhata asked if I would pay a visit to Act Hall and evaluate the situation.
When Mrs. Furuhata told me her story it jogged my memory of a recital by Mr. Yasui that I had heard at Tokyo's Tsuda Hall, also in 1996. I remembered the beautiful sound I had enjoyed at that recital, where Mr. Yasui performed on Tsuda Hall's Steinway. (After that concert, I learned that Mr. Inoue's piano tuning talent had also contributed to that recital's success.)
The week following my conversation with Mrs. Furuhata, I was scheduled to attend a concert at Harmony Hall in Matsumoto City. I took an early train and made a stop in Hatamachi to visit Act Hall. In my mind, I expected to find a low-ceilinged multipurpose hall. Much to my surprise, I discovered instead that the hall's ceiling is quite high enough, and that its acoustical woes stemmed from other causes.
All of the interior walls of Act Hall had been covered with porous, sound-absorbing panels, and the exposed slab ceiling had likewise been finished in a manner designed to absorb sound rather than reflect it back into the hall. Thus, the interior finishing of the hall thoroughly and effectively worked to deaden whatever beautiful music a performer might produce. In addition, the hall was equipped with an imposing speaker system (EAW) installed along the side walls at the stage end of the auditorium. This equipment, while undoubtedly top-of-the-line apparatus in and of itself, was extravagant and out of place in the context of Act Hall and the needs and objectives of the community that the hall serves. In sum, the hall's interior accouterments made the hall more like a fine performance space for rock 'n' roll than the multipurpose hall it was intended to be. As to how this miss-match of equipment and purpose occurred, my educated guess is that it reflects the recommendation of some acoustical equipment supplier who knew little about how a hall in a country town such as Hatamachi would in fact be used. To install a Bosendorfer piano here only compounded the incongruity since the Viennese-crafted Bosendorfer piano needs an acoustically rich environment in order to produce its optimal sound quality.
Measured Reverberation Time of Act Hall
Hatamachi's mayor, Mr. Fukazawa, was faced with a real dilemma. In having the town purchase the Bosendorfer piano, he had acceded to the lobbying efforts of Mrs. Furuhata and others who shared her desire for a rich classical music experience at Act Hall. However, the hall's construction and acoustical design, as described above, was a fait accompli left to Mr. Fukazawa from a previous mayor's administration. As things stood when I visited in the autumn of 1997, the hall was shunned by choral groups and consistently bad-mouthed by classical music fans. Whatever the long-term solution would be, Mrs. Furuhata's immediate priority and goal was to improve the acoustics of Act Hall before two piano recitals scheduled for July 1998. Though she lacked the funds for a true renovation effort, she was determined to do something, and this was why she had sought my advice and help. I provided two suggestions:
(1) Cover the underside of the hall's seating with a composite material so as to inhibit sound absorption; and,
(2) Add reflection panels to the forward portion of the proscenium.
The difference in reverberation time before and after the renovations to Act Hall are shown in the accompanying graph. The selective absorption characteristics of the porous wall paneling is very evident in the pre-renovation measurement. By changing a portion of these absorption characteristics into reflections, we improved some of the peculiarities of the hall's sound. Unfortunately, the renovations function only as a Band-Aid and not as a true remedy. While I did not have the opportunity to hear a recital in the hall prior to the renovation, when I attended the post-renovation recital of Yoko Tokue on July 11, 1998, I was not satisfied with the quality of the hall's sound. Hatamachi's classical music fans, however, graciously and sincerely assured me that the renovations greatly improved the hall's sound over what they had experienced before.
On the bright side, Act Hall is lucky to be a high-ceilinged structure. With the addition of a complete set of stage reflection panels and the renovation of the hall's entire interior materials, including the ceiling treatment, I am certain that this hall can be reborn as a superior-sounding multipurpose facility. I look forward to the people of Hatamachi stepping up to the challenge of making the acoustical potential of Act Hall a reality for all in their midst to enjoy.
Nagata Acoustics News 98-8iNo.128j
Issued : August 25, 1998
Nagata Acoustics Inc.