Feature: Dynamics of design
Feature: Dynamics of design
Marshall Day Acoustics has set a new benchmark for live performance venues in the fast-growing city of Chengdu. Caroline Moss learns about the company’s work on the Chengdu City Concert Hall
In the last issue of Pro AVL Asia, we profiled Marshall Day Acoustics and the progress the Australian company has made while working in China throughout the past two decades, designing some of the country’s most cutting-edge and architecturally striking performance venues, including opera houses, concert halls and specialist performance spaces in Beijing, Guangzhou, Xian, Zhuhai, Nanjing, Yixing and Qingdao. One of Marshall Day’s most recent projects is the RMB 2.5 billion Chengdu City Concert Hall in the capital of Sichuan province.
Working with its client, China Southwest Architectural Design and Research Institute Corp, Marshall Day designed four discreet venues within the complex – a 1,600-seat opera house, a 1,400-seat concert hall, a 400-seat drama theatre and a 200-seat recital hall – as well as associated spaces, including drama and orchestra rehearsal rooms, a recording studio and foyer areas. The early stages of the project were developed in association with the Sichuan Conservatorium of Music, whose input guided the architects in the preparation of the concept design. Recognising the importance of the highest-quality acoustic and technical design input, the client was prepared to employ international consultants to achieve its aim, and duly approached Marshall Day Acoustics based on the company’s aforementioned experience in China.
“Our approach is to work with the client, the architects and technical consultants to create unique outcomes for each of our projects,” explains Marshall Day Acoustics associate, Peter Exton. “Our understanding of the physical principles of acoustics allows us to tailor solutions in response to a wide variety of inputs regarding the practical and aesthetic demands of the design team.”
As in any project conducted away from the company HQ, a major challenge is keeping the channels of communication open, especially during the design phases. For the Chengdu City Concert Hall project, Marshall Day Acoustics’ design team in Hong Kong was led by Thomas Scelo. “Having worked together for many years, the trust developed within our wider room acoustics team allowed the sharing of the technical analysis and review of the refinements to the design,” continues Exton. “The team’s depth of experience and the common understanding within it ensured the quality of the final result and provided confidence for all of us through the concept and design development phases.”
The Marshall Day team was engaged in all the design workshops, establishing continuity with the client throughout the design and construction phases. Work commenced with a design concept that addressed many of the operational requirements for the venue. Room acoustic design criteria were developed for each of the four performance spaces in response to proposed uses, with an acoustic design strategy developed for each space. “Significant modifications were made to the original drawings to achieve appropriate room volumes, room proportions, balcony overhangs and the realisation of the principal acoustic reflection surfaces,” continues Exton.
Consultations on internal finishes for the rooms were then carried out with the architect and client, and coordination with the technical consultants located the technical infrastructure into the acoustic design with the goal of creating a seamless continuity of form and function in each room.
“This results in rooms with individuality, where the acoustic character and technical function are a natural consequence of the room geometry and materiality,” explains Exton. “During the design phases, most of the liaison with architects, technical consultants and interior designers starts with round table discussion. In this way, the dynamics of the design process are usually easily established and common goals for the project can be identified. Coordination of acoustically important surfaces with theatre equipment locations often takes some further working out and this discussion was mediated through the architects and design team. Our feedback into the design process consisted of regular technical documentation and design reports at the culmination of each design phase.”
As the Marshall Day team went about producing several iterations of design documentation, the designs were analysed using Odeon room acoustic prediction software to ensure that any changes had a beneficial effect on the acoustic outcome. The two largest venues within the complex – the opera house and the concert hall – needed to be addressed differently. The 17,800m3 concert hall comprises a raked stalls area, side galleries, choir and a balcony, seating a total audience of 1,400, and has been designed for non-amplified western symphonic, choral and chamber music. The 13,900m3 opera house, meanwhile, seats an audience of 1,600 in the stalls and two balconies and is designed for both amplified and non-amplified performances such as opera, drama and musical theatre and ballet.
As each has been designed for specific performance types, the acoustic demands were different. “In a concert hall for orchestral performance, the sound from all parts of the stage should blend to create a musical texture,” explains Exton. “The sound level should be full and immerse the audience. The sound of an individual instrument should be clear when needed but not dominate for a complete performance. In an opera house, the sound from the stage should project clearly and the location of the singer’s voice must be consistent with their position onstage. The stage performers should be able to soar above the level and presence of the orchestra. However, the orchestral sound must retain a full range of tone colour, without becoming overpowering.”
The acoustic differences were achieved in a combination of ways, one of which was to provide reverberation times of different lengths for each venue. A longer reverberation time encourages the blending of the orchestral sound for a symphony in a concert hall, conveying the fullness of the orchestra, while the clarity and loudness must allow all the details of the musical phrases and soloists’ work to project to the furthest seats. In some halls, the under-balcony area can be shielded from the reverberant sound, and a lot of care is needed to provide a satisfactory acoustic experience here. For an opera house, a shorter time will preserve the clarity of diction for the singer in the latter. “We generally incorporate a ceiling reflector into the design of an opera house,” he continues. “A reflection from overhead reinforces the singer’s direct sound, while maintaining the same direction as the sightline. For a concert hall, an over-stage reflector can be used to enhance the clarity for musicians onstage. For the concert audience, the reflections reaching them from the sides are more important as these promote envelopment in the performance.”
Marshall Day achieved a reverberation time of 2.3s in the unoccupied concert hall and 1.8s in the similarly unoccupied opera house – values that are slightly reduced during performances due to the additional absorption effect of the audiences.
Meyer Sound systems provided by Chinese distributor, Shanghai Broad Future, were installed into three of the spaces: the opera house, concert hall and recital hall. System integration was handled by the Dalian Yisheng Electronic Engineering Company.
A CAL 32 self-powered, beam-steering system was chosen for the concert hall, with two-column arrays covering the first and third floors and a four-column array on the second level. Meyer’s CAL series was developed primarily for vocal reproduction in fixed installations, producing a vertical beam of programmable width which can then be digitally steered up to 30° up or down to optimise intelligibility over large areas. The system is supplemented by four 600-HP compact, high-power subwoofers and a delay system of four UPA-1P wide-coverage speakers, plus six MJF-210 stage monitors. A Galileo Galaxy 816 network processor provides control over the audio system in the concert hall.
In the opera house, a point source system consisting of six UPQ-2P self-powered, narrow-coverage loudspeakers from Meyer Sound’s Ultra Series, with three 600-HP compact subs per side, was supplied by Shanghai Broad Future. Three of Meyer’s extremely compact MM-4XPs, designed for spot coverage in systems with space limitations and visibility concerns, provide front fill, with a further seven for the orchestra pit. Nine UPQ-1Ps are being used for stage side fill, and there are eight MJF-210 monitors onstage. Three Galileo 616 loudspeaker management systems handle driving and alignment for the opera house system, and power is provided by two MPS-488HP external PSUs.
The Chengdu project reached a particularly poignant conclusion for Exton thanks to a fortuitous discovery made during one of the final site inspections. At this stage of the project, Marshall Day was commissioning the concert hall before completing building works in the other venues. Walking back from lunch with the client near the Sichuan Conservatorium of Music, they passed several music shops including one that specialised in violins. For Exton, an accomplished professional violinist before taking up acoustics, this was too intriguing to walk past. The shop was run by Lin, a graduate of the Violin Making School of America in Salt Lake City, who now works in the shop established by his father, also a violin maker and repairer. “We enjoyed tea, a very friendly conversation about violins and the art of violin making, complete with a demonstration of the hand tools used by Lin in a way that has not changed since the craft was established in Northern Italy in the 17th century, and a tour of the workshop,” recalls Exton. “Two days later, another of Lin’s beautifully handmade instruments was returned to his shop and we were invited for a second visit to inspect it. This we did, and I enjoyed the opportunity of playing this instrument, which was remarkably full toned and responsive.”
A few months later, back in Chengdu for the acoustic testing of the other three venues and the rehearsal rooms, Exton was delighted to be loaned the instrument to accompany a soprano singer in the recital hall and smaller theatre.
“It was a pleasure to be reunited with Lin’s violin and demonstrate its clear sound in the new venue,” he says. “For me, the most significant moment of any project is entering the almost finished site to assess the result of years of preparation. For the first time, one can assess the atmosphere of the building and get a feeling for the whole venue. The character of each performance space is unveiled in turn, and each room becomes an instrument ready to enhance the sound from the musicians and transport it to future audiences. For this project, the most memorable moments were assessing the performance spaces, using our state-of-the-art measuring equipment for the objective tests – a scientific method of demonstrating accordance with our contractual agreement as part of the commissioning process. But, in this venue, I was able to extend the testing regimen using this beautiful, locally made violin to play in the space. This allowed the sound of the instrument to liberate the sound quality of the room. With the client and the violin maker, we could share the experience of the room coming to life and glimpse some of its potential as a venue for future performances. That was a privilege.”