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La Scena Musicale - Vol. 8, No. 1

The Artec of Sound

by Wah Keung Chan / September 2, 2002

Version française...

The common denominator in all of these halls is the acoustic design of Artec Consultants.

Everyone who attends a live performance experiences the thrill of the sound of music launched from the stage and reflected in the hall. Depending on the acoustics of the hall, the result can be good or great. Several major projects over the course of the next four years will see concert-going become a better listening experience -- because good natural acoustics are core to the designs.

Poor acoustics were the inspiration for the renovations undertaken at Toronto's Roy Thomson Hall over the last six months. Musicians and audiences alike have complained since its opening 20 years ago of the dead acoustics from the stage and inconsistent experiences according to the seats. Damian Doria, President of Artec Consultants, the acousticians for the project, blames the huge volume of space of the original design and the openings to the attic where sound is lost. When the hall officially reopens with a gala on September 21, among the solutions in the $20 million project is a series of 23 wooden bulkheads at the top of the hall that effectively reduces the volume of the hall by 13.5% (see side bar).

The announcement of the new Montreal Symphony concert hall and the new Canadian Opera Company Opera House in Toronto (the Four Seasons Centre for the Performing Arts) within three months of each other this spring has reinvigorated the prospect for excellent music making in both cities. Both houses should be ready in 2005. At the same time, new halls or studios are being planned at the Royal Conservatory of Music and McGill's Faculty of Music.

A Canadian trend

Canada already has a tradition of acoustically good halls: the Winspear in Edmonton, the Chan Centre in Vancouver, the Jack Singer Concert Hall in Calgary, the Weston Recital Hall in the Toronto Centre for the Arts, Domaine Forget in Charlevoix, all built in the last 20 years. The common denominator in all of these halls is the acoustic design of Artec Consultants. And not coincidentally, Artec are already the designated acousticians for the RCM and McGill projects, and they have submitted their candidature for the MSO hall as well. Artec did the acoustic design of the original COC opera house plan years ago, and the firm is in the running again this time.

Artec's track record has everything to do with their proven product. "It is very important for opera companies, symphonies, and government agencies that are searching for theatre planning consultants that somehow you have some very good finished projects not too far from them," says 78-year-old Artec founder, CEO and chief acoustician Russell Johnson, whom Norman Lebrecht in La Scena Musicale Online called the one man on earth who can give conductors the perfect sound. "When our opera houses open in Singapore and São Paulo, Brazil, we should increase our projects in those parts of the world. I started to work in Canada with the firm ARCOP in Montreal in 1955 and so we got started in Canada many decades ago and this gradually led to more and more projects."

Acoustic secrets

What are Artec's secrets of success? According to Doria, "Artec has focused throughout its history in making rooms extremely quiet. For a long time we've been using the threshold of hearing as a goal in background noise level in the hall, so that a person can't hear anything but that which is created in the performance. Engineers didn't want to believe that it is possible to achieve something like that -- most air conditioning and lighting systems create plenty of noise. Now with microphones, with the CD in the 1980s, we were faced with a situation where in order to have a recording without tremendous amounts of noise on it, you have to have a quiet room to begin with. Before that time, the recording and broadcast people didn't really care about some noise in their rooms, the quietest studio has quite a bit of noise. Back in the 1970s and 80s, Artec was already insisting on silent rooms long before anyone in broadcast and recording thought it was important, to allow the performers to create an intimate bond between themselves and the audience and to maximize the dynamic range in the room so as to be able to play pianissimo and be heard clearly."

Artec continues to push the envelope of silence: the McGill recording studio is slated to be the quietest in the world.

Many of Artec's successful halls are rectangular in shape. Explains Doria, "The rectangle or shoebox allows you to simultaneously achieve the sufficient amount of clarity with the long reverberation time. If you shape the hall based on the rectangle, you are creating a situation where there is strong lateral energy coming from the side walls which both create an enveloping sound and reinforce the clarity of sound. The sound that reaches the listener in the first 70-80 milliseconds reinforces, in the way you hear psycho-acoustically, the direct sound you are hearing from the performance in a way that adds a great amount of clarity. And if you make a fairly tall shoebox like many of our halls are, the sound that ends up at the top of the room filters back into the room later and gives you the long reverberence that many types of music look for. There are some reasonably successful alternatives, but they often have elements that are comparable to shoeboxes: hybrid forms that have a lot of narrow parallel surfaces, a lot of reflective ledges that are close to the audience. If the idea is to get the best acoustics with the best investment, then a shoebox is a very good place to start."

Planning an opera house

While Artec would not talk specifically about the COC project, they readily shared their experiences of opera houses. "The great houses of the past centuries were very tight volumes. The reason why they could fit enough into those spaces is because they didn't mind cramming people very close together. Today, we are concerned about how to get people out of a fire, meaning that you can fit fewer people into that tight volume.

"One of the primary goals in an opera house is to try to keep that volume tight and intimate, not just for acoustics but for the visual intimacy between the performers and the audience. Very often they end up being more of a horseshoe shape or almost circular shape. In order to create a sightline to the stage, you do tend to rake the seats more in an auditorium for an opera or ballet than you would need to in a concert hall. The acoustic detriment you try to overcome by the intimacy of the space. The higher rake absorbs more sound. In most opera, you are not looking for a very long reverb. Some of the greatest opera house have short reverb times, but they don't necessarily make great concert halls."

And what is the ideal space? Johnson offers a comparison: "The Metropolitain Opera is the wealthiest operation and has the money to hire the very finest singers in the world who can more or less cope successfully with the very large size of the Metropolitan Opera. Most opera companies now are building 1600 to 2100 seat rooms, and they will be used by singers who will be appropriate for the scale of these rooms. You will hear singers in those halls who would not fare well at all at the Metropolitan Opera."

Designing building and sound together

When a new performance centre is planned, the acoustician is often chosen before the architect to provide acoustic guidelines. "It's really a good collaborative effort," says Johnson. According to Thomas Payne of KPMB, architect of the Roy Thomson project, Artec suggested the main changes to the existing hall and it was up to the architect to make the design meet those specifications. Sometimes, due to budget, an implementation proceeds step by step over time. Over the past summer, thanks to a donor who cashed in from the Nortel bubble, the Winspear Centre in Edmonton installed a new organ constructed by Letourneau Organs of Quebec. According to Johnson, "We had already decided where the organ should be placed. Most concert halls have organs because of the symphonic repertoire for organ and orchestra. It turns the room into a pipe organ recital hall, and the pipes create an interesting visual." Having the organ placed at the centre line, above the choral seating behind the stage, as in the case of the Winspear, is a favourite design for Johnson. "The choral seats give the ticket buyers a wonderful view of the conductor and it helps to get additional seats in the hall," says Johnson.

Having reach the apex of their profession, are there any challenges remaining for Artec? Johnson demurs, saying, "It's extremely important to continue to develop our expertise. We are constantly trying to discover all things that didn't work, by looking for shortcomings, by looking for even the slightest improvements. We are constantly seeking the holy grail that will be the perfect room."

Elements of a Good Acoustic Hall

Wood, good reflecting surfaces, quiet lighting and air conditioning and an adjustable canopy are some elements contributing to making a good concert hall. According to Doria, the cost of quiet lighting and air conditioning is not really that much more expensive. "There is a small premium for quieter dimmers but it is really selecting the right kind of light fixtures and circuiting them correctly. Starting with a quiet fan unit with the proper size -- which in most cases is not really more expensive than a standard one -- and picking a point on its operating curve where it operates quietly as its normal operating condition. We design the air ducts so that there is enough length between the fan and the room so the fan is not heard, and we make gentle turns in the ducts in order not to generate a lot of air flow noise within the ductwork itself." At the press conference unvealing Roy Thomson Hall, the officials proudly announced that every seat was computer modelled acoustically seven years ago. "Every surface in the room can be assigned an absorption factor in a computer, to arrive at the probable reverb time," said Doria. The 23 bulkheads serve not only to reduce the volume of the space and give the hall more rectangular characteristics, its sandblasted maple finish reflects sound back. Sound-absorbing banners can be lowered to cover the bulkheads to reduce reverb for amplified concerts. Visually, the most noticeable feature of the new Roy Thomson Hall is its movable circular and crescent-shaped canopies located above the stage that house the stage lights, also found in the Chan Centre and many other Artec halls. The canopy reflects sound back to both the stage and audience to solve the problem of dry acoustics for the musicians. The idea is to raise the canopies as much as possible for large orchestral works and lower them for solo recitals; adjustments can be made during intermission. Before the September 21 opening, Artec engineers will be working for a month with musicians from the TSO and other ensembles to arrive at optimal settings. When the adjustable features are not optimized, the results can be disappointing. Philadelphia's Kimmel Centre (another Artec project) opened last December to mixed reviews. Said Johnson, "The building owners decided to open nine months ahead of schedule. There were many features that were not installed at the time."

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