In-key construction: acoustic design
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In-key construction: acoustic design

01 Sep 2011 (Last Updated October 22nd, 2021 07:07)

New concert halls in Reykjavik and elsewhere are leading a wave of advanced design and construction. Guided by sophisticated quantitative analyses and close collaborations between architects and acousticians, these facilities combine art and science to optimise the production and reception of music. Bill Millard investigates.

The transparent calcite known as Iceland spar exerts a double-refraction effect on light passing through it, creating two separate polarised patterns. View anything through this crystal, and the doubled image is liable to trigger speculation about the nature of transparency, the processes of mediation and context, and the impossibility of direct and pure perception.

It’s also a reasonably helpful metaphor for other kinds of sensation, specifically musical ones. Any time we hear a purposeful sonic event inside a building, we’re hearing not only the performance itself, but also its surroundings, through reverberation and acoustic focusing. What we hear, like what we see through Iceland spar, reaches us more than once. A hall is an instrument just like the resonating bodies of violins and bells of horns.

One of the four music chambers in Reykjavik’s new Harpa complex takes its name from the local term for that birefringent mineral, Silfurberg. Harpa, along with new concert halls opening in Helsinki, Kansas City, Paris, Montréal, and elsewhere, represents the forward edge of performance-space design, drawing on evolving traditions and technological advances to build settings that combine clarity, resonance, evenly distributed volume, isolation from external sounds and HVAC noise, and hard-to-define timbral qualities to optimise not only measurable standards but the fully nuanced communication between musicians and listeners.

“Harpa is a 28,000m² complex named for both the instrument and the first month of spring in the Icelandic calendar.”

Harpa, a 28,000m² complex named for both the instrument and the first month of spring in the Icelandic calendar, is the most visually striking of the lot; it is already drawing ample attention for its profile evoking Iceland’s geologic formations and its coloured glass façade (the work of Copenhagen-based Henning Larsen Architects, Danish-Icelandic sculptor Olafur Eliasson and local firm Batteríið). On many levels, Harpa brings the promise of renewal to a troubled place, but music is its purpose. It is the new home of the Iceland Symphony Orchestra (ISO); its smaller halls are suited to jazz, rock and pop; and in a mid-plan programme expansion, it will also house the Icelandic Opera.

Shape up

Conventional wisdom long held that a shoebox shape, with all or most seats facing directly forward, was the optimal geometry for any concert hall. A tall, narrow rectangular volume concentrates reverberation, producing a richer sense of space than fan-shaped auditoria, which lack side reflection, as do open-air arrangements. Vienna’s Musikverein (Theophil von Hansen, 1870), Amsterdam’s Concertgebouw (Adolf Leonard van Gendt, 1888), and Boston’s Symphony Hall (McKim, Mead & White, 1900) are among the many highly respected halls built on the shoebox model – notably, traditionalists point out, before the rise of modern acoustic science. Many top-rank contemporary halls adhere to the shoebox principle, often while directing innovations elsewhere: Porto’s Casa de Musica (OMA, 2005); l’Adresse symphonique, the new home of the Orchestre Symphonique de Montréal (Diamond + Schmitt, 2011, forthcoming); and Harpa’s main concert hall, Eldborg.

The downsides of shoebox design (aside from formal constraints for the architect) include large variation in sightlines and sonic immediacy; the hierarchy between the best and worst seats is extreme. Excessive scale can defeat even the combination of the reliable shoebox and careful acoustic engineering, as in New York’s Avery Fisher Hall in its original 1962 form: pressure to increase seating capacity overrode the ideas of acousticians Bolt, Beranek and Newman (BBN) and architect Max Abramovitz, leaving few performers or critics satisfied. Changes in music, too, highlight the close relationship of certain built spaces and symphonic styles; musical modernism’s harmonic complexity and timbral precision can be ill at ease in halls designed to maximise the symphonic power and emotion of later romanticism. Amplification calls for different acoustical properties altogether.

Hans Scharoun’s tent-shaped 1963 design for the Berliner Philharmonie was a game-changer, says Dr Yasuhisa Toyota, president of the US office of Nagata Acoustics in Los Angeles. Arena-style or vineyard configurations, distributing the audience in multiple terraces beside and behind the stage, improve sightlines and bring more of the audience closer to the performers, increasing “visual intimacy,” Toyota says. “I think this is one of the most important points for architectural design, to take arena style rather than conventional shoebox.”

“Harpa gives the ISO the world-class performance space it has long deserved.”

Asymmetry is a virtue, he continues, noting that orchestras themselves are configured asymmetrically, placing higher and lower string sections at opposite sides of the stage. The vineyard design (a terraced arena shape) affects the psycho-acoustic aspects of listening, giving more listeners the immersive perception that a shoebox reserves for the front rows. Toyota’s Suntory Hall in Tokyo (Yasui Architects & Engineers, 1986) advanced the Philharmonie’s tradition, and in later projects like Walt Disney Hall in Los Angeles (Frank Gehry, 2003), Copenhagen’s Danish Radio Concert Hall (Jean Nouvel, 2009), Miami’s New World Music Center (Gehry, 2011), the Helsinki Music Centre (Laiho-Pulkkinen-Raunio, August 2011), the twin-halled Kauffman Center for the Performing Arts in Kansas City (Moshe Safdie, opening September 2011), and the forthcoming Philharmonie de Paris (consulting with Nouvel and another acoustics firm, New Zealand’s Marshall Day), he has become a world-leading practitioner and advocate of sculpted vineyard-style design.

Toyota acknowledges that Vineyard designs present more challenges than the shoebox. “They were very difficult when we didn’t have computer technology. I’d say more than 20 to 30 years ago it was almost impossible. But now the computers have made it possible to calculate or to simulate those complicated room shapes acoustically.” Extrapolations from physical-model studies can yield uncertain results, but digital modelling affords precise analyses to guide the design of room shapes, arrangement of materials, and placement of seats, resonance chambers, or devices for localised diffusion or damping such as panels, canopies, baffles or banners.

Toyota emphasises the right instrument for the job on every scale, from analytic programmes to full buildings. He favours different hall typologies for amplified and unamplified music. “I don’t think it’s a good idea to involve many programmes of rock ‘n’ roll or pop music into a concert hall space, which should be designed for natural acoustics, for classical music,” he says.

Quantitative measurements are essential, but Toyota cautions that numbers tell only part of the story, failing to fully capture the quality of acoustics. What does capture it is an understanding of which details matter and the capacity to make adjustments. Visibly prominent elements and acoustically significant ones are two different categories. Types of wood on ceilings and walls aren’t particularly important, Toyota says, but the wood chosen for the stage floor, which transmits vibrations directly from pianos, cellos and double basses, is critical (Alaskan cedar is a favourite in several of his collaborations with Gehry and in Helzberg Hall). Tuning up the flexible components such as dampers, resonance chambers, and the most powerful variable – an orchestra’s familiarity with its new home – often takes several months between initial rehearsals and the opening concert.

“Numbers tell only part of the story, failing to fully capture the quality of acoustics.”

The techniques that make vineyard configurations feasible are not limited to them; today’s shoebox halls benefit from the same analyses and adjustments. “These buildings are sort of like Swiss watches,” says Edward Arenius, a partner at Artec, the New York acoustics firm that worked with Henning Larsen and colleagues on Harpa. They require fine-tuning that is both an engineering discipline and an art form. Treating their built projects as ‘full-size models’, Arenius and his colleagues study large numbers of performances, map the intensity of hot spots or dead zones, adjust physical details accordingly, and use digital signal processing to regulate speaker performance in halls where events are amplified. With a large twopiece canopy for overhead reflection, coupled acoustic control chambers with mechanised doors, and absorptive fabric controlled by tube motors, Harpa offers multiple options for adjusting room tone. Arenius finds it important to resist the financial imperative to overload the hall with seating.

Harpa: better by design

Peer Teglgaard Jeppesen, the Henning Larsen partner and director responsible for Harpa, describes the design’s evolution between 1999, when city and national officials first announced Reykjavik’s East Harbour Project master plan, and the construction phase. Unlike Helsinki, where optimal acoustics were the chief motive for the project, Harpa responds to a diverse brief: its aims include strengthening the city’s connection with the ocean, serving as a civic and national icon that evokes Iceland’s basalt formations and distinctive light patterns, and expanding capacity for large meetings, as well as giving the ISO the world-class performance space that it had long deserved. Folding the Icelandic Opera into the programme meant considering complex scenery, costuming and staging facilities (“a concert hall is not an opera,” Jeppesen notes dryly). “We knew from the start that they wanted to incorporate some operatic programmes,” Arenius says. “What was surprising to us is the level of operatic quality sought.”

The four-chamber plan allows Harpa to incorporate a wide range of programmes, including loud rock ‘n’ roll unsuitable for Eldborg, which is optimised for acoustic music. The 450-seat Norðurljós (‘Northern Lights’) accommodates orchestral and operatic rehearsals and recitals, while the flat-floored, 750-seat conference hall Silfurberg is ideal for rock and dance events. Kaldalón (‘Cold Lagoon’, a north-western fjord), a steeply raked 200-seat fourth hall on the ground floor, which is appropriate for lectures and smaller recitals, has also been popular for low-cost bookings from local groups.

Isolating the rooms acoustically requires massive concrete envelopes around each, along with a complete acoustic joint around Eldborg. “We have a philosophy that you want to maintain clarity and reverberation at the same time,” says Arenius, “and that’s why we’re very fond of these coupled-volume spaces, where you have an inner concert hall of whatever shape, form and size, and a secondary volume that flanks it.” Harpa opened for performances in May 2011, though production defects in some steel framing elements meant the façade was unfinished in time for the launch; the full facility officially opened on 20 August, Reykjavik’s Culture Night.

“On many levels, Harpa brings the promise of renewal to a troubled place, but music is its purpose.”

Its primary user, the ISO, is delighted. First violinist and concertmaster Sigrún Eðvaldsdóttir describes the experience of playing in Eldborg as “a big shock after all these years in a really bad hall.” Her first impression, perhaps implying that shoeboxes and vineyards need not always be far apart, was that it resembled the Berliner Philharmonie. Violinists and woodwind players are particularly pleased with the clarity, and the percussionists are ‘ecstatically happy’. Pianissimo passages that could get lost in the old quarters are now clear; the improvement is drastic enough that the players need some time to adjust their style. “The section leaders are a little nervous because sometimes we feel like we cannot hear each other very well, but I think that’s a matter of getting used to it. This orchestra now has to trust that when we play softly, it will carry.”

Music critics, Eðvaldsdóttir reports, have commented “that for the first time they are hearing all the dynamics… how nice it was to hear the pianissimo properly.” ISO conductor laureate and Harpa artistic adviser Vladimir Ashkenazy is, she adds, “so used to great halls, he just thinks it’s about time we finally had one.”

Economically, there could hardly have been a worse time to have a major facility under construction. Supported by a public-private partnership, initially intended to anchor a hotel/retail/ residential/commercial complex under the ambitious name ‘World Trade Centre Reykjavik’, the commercial component dwindled as the economy crashed, and Harpa reorganised, facing inevitable controversy over its costs. But Iceland’s civic priorities continue to include its unique cultural heritage, and it has sustained the commitment that allowed Henning Larsen’s team to create a structure that resonates in many more senses than the literal.