News 14-11 (No.323)
Issued : November 25, 2014
New Concert Hall Opens in Katowice, Poland
By Dr. Yasuhisa Toyota
Photo-1 New Concert Hall in Katowice
Photo-2 Interior of the Concert Hall
Photo-3 Interior of the Concert Hall
In last month’s newsletter I wrote about the opening of a new hall in Shanghai and this month, in quick succession, I will write about the opening of another new and significant concert hall. On October 1, 2014, a new concert hall opened in Katowice, Poland. Katowice is located in southern Poland in an area also known as Upper Silesia. The city functions as a regional hub and is home to 300,000 people. In the early 20th century the city flourished as a center of coal mining production but when the coal mining industry fell into decline in the later part of the century so did the city. The catalyst for Katowice’s revival has been culture and the arts.
<< The History of NOSPR in Katowice >>
In addition to the general goal of promoting the performing arts in Katowice, there was another good reason to build a new concert hall in this city. Poland has two national orchestras. One is the Warsaw Philharmonic Orchestra, based in that city, and other is the Katowice-based “Narodowa Orkiestra Symfoniczna Polskiego Radia w Katowicach”, or “NOSPR”, the Polish National Radio Symphony Orchestra.
NOSPR was originally founded in 1935 in Warsaw, but its activities were interrupted by the outbreak of World War II. When the orchestra came together again in 1945 it did so in Katowice, where it continues to make its home through the present day. From its very beginnings until the recent opening of the new hall in Katowice, the dream and aspiration of the orchestra and its players has been to perform in a concert hall with fine acoustics that they can call their own home hall.
<< Project Participants >>
In December, 2008, the local Katowice architectural firm of Tomasz Konior won the competition for the role of project architect. In addition, the project had the ongoing support of internationally renowned Polish pianist Krystian Zimerman who was born actually in this region, who served as advisor to the project. Mr. Zimerman builds his own pianos and tunes them himself for his concert performances, demonstrating both his keen knowledge of his instrument and his intense particularity about the tone colors of the pianos he plays.
Mr. Zimerman’s interest in acoustics also extends to concert hall acoustics. He devised his own acoustical measuring device for halls and he has taken the device to halls around the world to gather acoustical data. In his capacity as advisor to the Katowice Hall project, Mr. Zimerman proposed that Nagata Acoustics be awarded the acoustical consulting role on the project. Because of his recommendation, we were invited to join the project team.
Tomasz Konior had collaborated with local acoustical consultant Pracownia Akustyczna to prepare the architect selection competition’s winning design, so portions of the project were also awarded to this consultant. Specifically, we designed the room acoustics for the 1,800-seat main hall and Pracownia Akustyczna was awarded responsibility for the small hall’s acoustical room design as well as the overall sound isolation and noise prevention design and the halls’ sound system designs.
<< Room Configuration of Katowice Main Hall >>
Figure-1 Plan of the Concert Hall
Figure-2 Longitudinal Section of the Concert Hall
Figure-3 Cross Section of the Concert Hall
The winning proposal of the project’s architectural competition featured a traditional shoebox configuration for the main hall and the early stage of the project proceeded with this design. When we joined the project we reviewed the plans and offered a number of recommendations. As a result of this review process, our design of the main hall continued to use the shoebox configuration as a starting point. Nevertheless, we adapted the configuration by increasing the width of the hall beyond a typical shoebox shape and adding audience seating around all sides of the stage.
In revising the main hall’s configuration, our foremost consideration was how to shorten the distance between the audience seating and the stage. The purpose of this objective was to increase the sense of intimacy from the visual and acoustical perspectives. The result can be seen in the plan and section diagrams (Figures 1 - 3) that accompany this article. The main hall has a total spatial volume of 22,000 cu. m. (776,923 cu. ft).
Initially, the management of the new hall’s resident orchestra, NOSPR, disliked the idea of placing seating on all sides of the stage. However, as part of the design planning process the NOSPR’s management visited Copenhagen’s Danish Radio Concert Hall, a project that we completed in 2009. After experiencing a rehearsal and actual concert with the Danish National Symphony Orchestra in the Danish Radio Concert Hall, the NOSPR’s management changed their opinion of the planned design and enthusiastically supported our proposed audience seating arrangement.
<< Preventing Echoes and Obtaining Rich Reverberations >>
For the most part, we did not install sound absorbing elements in the Katowice main hall. However, because our 1/10 scale acoustic model testing, we conducted in the late design process, predicted that sound reflections from the rear wall of the hall would generate some echoes, we installed sound absorption material on portions of that wall.At the completion of construction we took acoustical measurements in the hall and obtained a sound reverberation time of 2.3 seconds (in an empty hall, at 500 Hz). The reverberation time of the full hall is 2.1 seconds at 500 Hz (calculated value based on the measured empty hall value).
<< NOSPR First Day in Their New Home >>
The orchestra held its first rehearsal in the new hall at the end of August. At the start of the session I could see the players looking nervously from one to other as they began to play. Inevitably, this is the most stressful moment of a new concert hall project.
Every new concert hall and its resident orchestra traverse a period of time that might best be called a birthing process. The orchestra begins to play and, as hours pass, the players become accustomed to their new surroundings. As each individual player becomes comfortable with the new acoustics, the ensemble’s sound coalesces and its fine and distinctive personality takes advantage of the new hall’s acoustics. As this evolution continues, the orchestra increasingly gains confidence and satisfaction with the new hall’s acoustics.
What differs about the birthing process from one hall to the next is a question of degree. Different orchestras take more or less time to acclimate to their new acoustics. In the Katowice main hall I saw this process evolve first hand and I noticed something else that differed from most other first days I’ve attended. From the very first notes, I immediately heard good balance in the NOSPR’s ensemble. And—as might well be expected because of this good start—the orchestra’s players began to express their appreciation of the new hall’s acoustics from the beginning of their first rehearsal.
Our biggest test of the new hall’s acoustics came during this first rehearsal when Mr. Zimerman took the stage. Because of this pianist’s stature in this area of his birth, it is safe to say that for the hall’s acoustics to be well received by all, we needed a thumbs up from Mr. Zimerman.
Happily, Mr. Zimerman could not have been more delighted with the new hall’s acoustics. He returned to the empty hall on the evening before its opening night and—alone on the stage of the new hall—played for hours late into the night. As the principal acoustical consultant on the project, I can truly say that when Mr. Zimerman gave his approval of this hall’s acoustics I breathed a sigh of relief. I am glad that this project came to such a successful conclusion.
More information about the new concert hall and the NOSPR can be found on the NOSPR website.
Building Isolation: Eliminating Subway Train Structure-Borne Sound at Shanghai Symphony Hall
By Dr. Keiji Oguchi
In this article I will continue our reporting on the new Shanghai Symphony Hall discussed by Yasuhisa Toyota in last month’s issue. This time, I will focus on the measures we implemented to prevent structure-borne noise transmission from underground trains that run close to the hall.
Before I discuss the specifics of the Shanghai Symphony Hall project implementation, I will review the analysis process we use to determine the most effective strategy or combination of strategies for each project’s vibration isolation. First, we investigate if there are ways to control the vibration at their source. Second, we try to situate the building as far as possible from the source of the vibration. Lastly, we isolate the vibration from the building by adopting a box-in-box or other structural design. In the case of Shanghai Symphony Hall, the project faced a location constraint because the project site is located in close proximity to underground train lines. Therefore, we focused our vibration isolation design on strategies that built the needed vibration isolation properties into the building’s structural design.
<< The Shanghai Symphony Hall Building’s Location >>
Shanghai Symphony Hall is located in the Hengshan - Fuxing Road area of the city’s Xuhui District, a neighborhood designated as an historical and cultural preservation area where architecturally significant historic buildings and old sycamore trees still line the streets. A system of highways traverses land near the south, north and west sides of the hall’s site and the Number 2, 7 and 10 subway lines run underground below the highways.
In particular, the Number 10 line runs very close to the hall’s site at its south side and a segment of the train line runs below a portion of the hall’s site. Because Hengshan - Fuxing Road area is a historical and cultural preservation area, buildings have a height restriction of 12 m. (39 ft), though its height can locally exceed this restriction. In the case of a concert hall, we aim to achieve a ceiling height greater than 12 m. high, so if the building height restriction is 12 m., our only option is to use a design that places a portion of the hall below ground. Such a design would, however, bring Shanghai Symphony Hall hall closer to the train line than if the project was built entirely above ground.
Figure-1 Plan View of Underground Train Line and Hall
Figure-2 Section View of Underground Line and Hall
Adjacent to the north boundary of the hall’s site is an area with low-rise homes. While we would have wished to shift the concert hall towards the north, the nearby residential housing also prevented us from creating physical distance between the hall and the underground train lines. We did not have the option of moving the hall’s location along the “y axis” and we could only achieve the needed ceiling height by locating a portion of the hall below ground. As a result, the completed Shanghai Symphony Hall is a mere 7.5 m. (25 ft) from the Number 10 train line’s tunnel, measured along the “y axis” and has an average distance from the tunnel of 15 m. (49 ft). The top of the train line tunnel is nearly the same depth as that of the stages of the two halls in the Shanghai Symphony Hall building. (Figure 1 shows a plan view of the underground train line and the hall. Figure 2 shows a section view of the underground train line and the hall.)
<< Vibrations Generated by Underground Trains >>
The Number 10 subway line is a new train line that the city of Shanghai built for the 2010 Shanghai World Expo. The Shanghai Symphony Hall project overlapped with the construction of this new train line and the hall project was informed that the rail line construction would include trackbed isolation—a design feature that would reduce the vibration generated by trains.
The Shanghai Symphony Hall project’s schedule did not allow us to wait until the train line’s completion to measure its vibration. Instead, we measured the vibration at another subway line that was already in operation and where a similar mitigation strategy had already been installed. Based on our findings at this similar location, we determined that we would need to reduce the vibration transmitted from the train line to the hall by approximately 20 dB in order to prevent the structure-borne noise caused by the transmitted train vibration from being heard during concerts in the new hall.
<< Vibration Isolation Strategy for Shanghai Symphony Hall >>
In Japan, a project to reduce vibrations by 20 dB would typically implement multiple strategies. For example, we might begin by constructing a slurry wall with vibration isolation mat around the building periphery. (Explained another way, for this part of the strategy we would insert flexible, rubbery material in a shallow moat surrounding the building.) Another part of our strategy might be to use box-in-box structural designs for designated rooms that require a specifc level of quietness. These are just two examples among a number of typical structure-borne noise isolation methods.
For Shanghai Symphony Hall we proposed and implemented a building isolation approach that encased the Concert Hall and the Hall for Chamber Music in two separate concrete boxes, and we combined this strategy with placing each concrete box on a system of steel springs. We decided to propose this comprehensive strategy because of the below 3 considerations:
Photo-1 Steel Spring System
Photo-2 Steel Spring System
To reduce the train vibration by 20 dB with a box-in-box structure, that is with a mass-spring system, we would need to set the natural frequency of the mass-spring system of less than 5 Hz. Using a rubber for this system would not accomplish this, but the use of a steel spring system could achieve this objective.
Implementing the kind of box-in-box design typically used in Japan requires very specific construction management knowledge during installation of vibration insulation in the vicinity of the box-in-box structure. Japan has a number of specialty contractors with years of experience doing this work. In Shanghai, we did not have vendors with comparable experience. Installing the steel spring system would use construction methods that the local construction teams could implement with a high level of competency and that would achieve the required vibration isolation characteristics.
In general, box-in-box designs use lightweight multi-layer board as a primary material for both the sound isolation layer and the interior of a room. Shanghai Symphony Hall’s Concert Hall uses solid and weighty materials in much of its interior design. We developed a building isolation approach using heavy materials and thereby matched the weight of the vibration isolation design materials to the weight of other materials used in the project.
The German company GERB was hired to develop the specifications, design the layout and procure the spring system as well as to manage the system’s installation. This company has a local office in Qingdao, China. Construction of the building isolation system can be seen in the two photos that accompany this article.
<< Achieved Quietness in the Concert Hall >>
A few days before the completion of construction at Shanghai Symphony Hall we measured the noise from the subway lines both outside and inside the halls in the building and we also did our own listening evaluations. In both halls, we obtained noise levels of less than NC-15 (measured with the hall’s HVAC systems in operation).
Inside each of the halls, the human ear could not hear any train noise. However, when we stepped outside the halls in the building, we could surely hear the trains. When we measured the the structure-borne train noise at the outside of the halls, it was between NC-25 and NC-30. We had validated the success of our design and its implementation.
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
2130 Sawtelle Blvd., Suite 308
Los Angeles, CA 90025, U.S.A.
Tel: +1-310-231-7878, Fax: +1-310-231-7816
75, avenue Parmentier
75011 Paris, France
Tel: +33 (0)1 40 21 44 25, Fax: +33 (0)1 40 21 24 00