Benaroya Hall: Sound Is Everything

AS THE CITY awaits the opening of the Seattle Symphony's new concert hall, worry mixes with anticipation. Will the hall live up to its promise? No one will know until the baton goes down on the first performance.

Sometimes the most important things are invisible.

You can see the curved glass and limestone facade of the new downtown Benaroya Hall, as the project moves into its last two months of completion. But the most vital aspect of the hall will remain unknown until a few weeks before Benaroya opens in a blaze of international fanfare Sept. 12.

It's the acoustics.

The sound of Benaroya Hall is its raison d'etre. If the symphony's $118.1 million gamble pays off, the orchestra will sound with new clarity and precision, better than it ever did in the larger, deader Opera House.

If the acoustics are poor - if they're even mediocre - the hall will need a costly, time-consuming and embarrassing redesign like the one undergone by San Francisco's Davies Hall, which opened in 1980 and then required major remodeling in 1991 and 1992.

The list of variables that affect acoustics - site, configuration, materials, reflective surfaces - is virtually infinite, and though every effort is being made to assure good acoustics, the science is inexact. We won't know whether Benaroya is fabulous or flawed until the first notes are sounded with an audience member in every seat. The audience itself is an important acoustical element - the largest absorber of sound in the hall.

The symphony is gambling on a known quantity. At the insistence of music director Gerard Schwarz, New Yorker Cyril Harris was chosen as the Symphony's acoustical consultant. In acoustics, Harris is a guy with a track record as good as Seattle Slew's.

Now 81, but energetic enough to climb through the unfinished hall like a mountain goat, he writes books, lectures at Columbia University and has a long list of acoustically successful halls to his credit - including Washington, D.C.'s Kennedy Center; the 1976 redesign of New York's Avery Fisher Hall; Minneapolis' Orchestra Hall; New York's Metropolitan Opera House; and Salt Lake City's Abravanel Hall.

Not even Harris, however, is infallible. His 1976 redesign of New York's Avery Fisher Hall was the subject of a laudatory profile, of the length and breadth usually devoted to heads of state or serial killers, in the highly regarded New Yorker magazine. But despite the high praise, the hall wasn't perfect. There are still complaints about bass weakness, for example, and in 1992, the hall underwent a substantial stage modification designed to improve one of the crucial aspects of concert-hall acoustics: the way the musicians hear each other on stage.

No sirens, no rumbles To ensure great sound in a concert hall, there are two requirements: Get rid of all the bad sound (noise from the outside and the ventilation system) and make the most of all the good sound (the music from the stage).

The siting of Benaroya Hall, between Union and University streets, and Second and Third avenues, posed an extra challenge. The architects had to contend with a railroad tunnel running diagonally beneath the auditorium, and an underground bus tunnel nearby.

Harris and the architectural design team, headed by Mark Reddington of Seattle's Loschky Marquardt & Nesholm firm (LMN), had a slab of concrete more than 6 feet thick poured under the hall to swallow the sound from the tunnels.

To combat other exterior noise, the designers made Benaroya a building within a building.

Stepping into the auditorium, concertgoers will step past a 9-inch gap called a "sound lock" into the interior structure, where everything from the ventilation system to the rate the sound-absorbent doors close has been designed to minimize noise.

The stage and the auditorium floor are all wood on a sub-frame system that "floats" above the concrete main floor. The 27-million-pound auditorium rests on 310 rubber bearings, each 15 inches square; this should further eliminate vibrations from below.

If the designers succeeded, and the hall is free of the rumbles, the street sirens and the overhead airplane noise, Benaroya Hall will be a desirable facility for recordings, as well as for concerts.

What our ears want to hear Optimizing the sound inside the new hall was an even tougher task than keeping the noise out.

Today's music lovers judge the success of a concert hall by a standard that has developed over two centuries. Most of the orchestral repertoire, composed since the end of the 18th century, was written mainly for performance in the great concert halls of Europe or in modern halls that emulate them.

Most of these halls have a lot of common characteristics. The basic design, generally called "the shoe box," is an elongated rectangle that most consistently supplies what our ears consider ideal acoustics for symphonic music.

This design provides a mixture of direct sound from the orchestra and reflected sound from the room's interior surfaces. The more that reflected sound is broken up and dispersed, the more pleasing it is to our ears.

Sound reflected off flat, straight walls is said to have a "glare," the auditory equivalent of what you see when you go skiing on a brilliantly sunny day.

The historical concert halls used wood and plaster surfaces, and lavish decorative detail (including pillars and statuary), and our ears have evolved to prefer the way these elements disperse and reflect sound. That's why Benaroya Hall has a lot of interior wood and plaster, and why you'll see some interior surfaces covered with truncated pyramids, "bumps."

"It's important to get the hall right the first time," Harris says, "because most of the ways to tinker with the sound don't work. Some halls have ceilings that go up and down, for instance, to control the volume of the hall."

Those ceilings, Harris notes, don't work acoustically, and often don't work mechanically.

"One of those ceilings, in San Jose, fell to the floor one night about 30 years ago. Luckily, the hall was empty at the time."

You can't copy a Stradivarius Despite his preference for the shoe box, Harris does not use a single model for concert-hall design and neither do most other acoustical experts.

One acoustician, Leo Beranek, has observed that "a concert hall is a musical instrument."

Copying musical instruments, like copying hall design, doesn't work. Since the early 18th century, violin makers have tried to copy the great Stradivarius instruments, considered the best-sounding violins ever made. They analyze the instruments down to the chemical components of the varnish.

But they've all failed. The only one to make a Stradivarius was Stradivari himself; similarly, there's only one Grosser Musikvereinssaal, the famed concert hall in Vienna, which has been called "the Mecca of the old halls of Europe," and there's only one Amsterdam Concertgebouw, which opened in 1888 and is considered one of the world's best.

Harris says he has long since quit trying to copy any specific hall.

"When I was first starting out," he says, "I thought we would find the answer (a universal design for perfect acoustics). But we're as far away now as ever. There are too many dependent variables for a single model to work every time."

But principles of those great halls can be studied, assessed, assimilated and applied. At Benaroya, Harris has engaged in what Reddington calls "a very disciplined process of testing and analysis, with no compromising whatsoever." Not only in the main 2,500-seat hall, but also in the smaller, 540-seat recital hall, the walls are shaped to diffuse sound.

The truncated-pyramid-shaped panels on the side walls, back walls and ceilings vary in size so that some reflect low frequencies and others reflect high frequencies. If you were to tap each panel, you'd get a slightly different pitch from each.

All the wood veneer on the side and back walls of Benaroya is from a single South African mahogany tree called the Makore.

Beautiful in their rich color and wood grain, the polished wall surfaces give the impression you're standing inside a very large cello.

"Nothing is going to absorb sound," Harris says, "except for the seats and the people." A carpet down the main-floor aisles is the only exception to a purely reflective floor, which extends to tongue-and-groove oak flooring everywhere else.

Reddington and Harris spent months, and an estimated $40,000, testing different seating materials for their absorbent qualities in every frequency of the sound spectrum. Harris analyzed the coating, padding and every other aspect, measuring the seats' sound absorption in an acoustical chamber. They settled on bare wood for the seat backs and low-nap upholstery for the seats.

The design team considered 30 to 40 ways to surface the side-wall boxes, laid out in three tiers around the hall. They wound up with an intricate variety of reflective shapes that provide what Reddington calls "huge amounts of diffusing surfaces, right down to 3-inch-wide details."

A matter of taste An important fact about acoustics: Perceived sound is to some degree a function of individual taste and experience.

Nearly all professional musicians agree on a short list of the world's great concert halls, which would start with such examples as the Grosser Musikvereinssaal, the Concertgebouw and Boston's Symphony Hall, and would probably include New York's Carnegie Hall, Grosser Tonhallesaal in Zurich, Berlin's Konzerthaus, St. David's Hall in Cardiff, Wales, Tokyo's smaller but excellent Hamarikyu Asahi, and Stadt-Casino in Basel, Switzerland.

But ask any noted conductor - and conductors are considered the real judges - and you'll get different versions of what constitutes first-class acoustics.

Legendary conductor Bruno Walter called the Vienna hall "certainly the finest in the world," but Herbert von Karajan of the Berlin Philharmonic complained that the sound was so full that the technical attack of instruments gets lost, and Dmitri Mitropolous, a past maestro of the New York Philharmonic, said it "rings too much."

Other halls, including Carnegie, have drawn a similar spectrum of acoustical critiques.

In short, no matter how great the acoustics at Benaroya Hall may be, there will be knowledgable naysayers to tell you it can't compare with a really great hall elsewhere.

It's not all subjective, as any member of the Acoustical Society of America - 2,000 of whose members are convening in Seattle this coming week - can tell you.

Extensive measurements applied to the world's most successful halls show that all share certain characteristics. They all have reverberation times of around two seconds (that's the length of time it takes for a loud tone to decay to inaudibility.)

Halls with a shorter reverberation time are sometimes called "dead" or "dry" - that's why most of the complaints about Carnegie Hall, with a reverberation time of around 1.8 seconds when there's an audience in the hall, cite a dry sound.

It's not unusual for cathedrals to have reverberation times of as much as 10 seconds; orchestral music usually sounds terrible in a cathedral.

In acoustics, size matters. That's why the Opera House, designed as an all-purpose facility, doesn't favor a symphony orchestra. The volume of sound in that fan-shaped area of 3,000 seats is simply too great.

Most of the world's great concert halls are much smaller: the Concertgebouw has 2,037 seats; the Vienna hall has only 1,680. Boston, at 2,625, and Carnegie, at 2,804, are considerably bigger, but another factor - the cubic volume of the hall - is nearly the same between Boston and the Concertgebouw; both are around 18,000 cubic meters.

In terms of volume per person, another measure, Benaroya Hall is strikingly close to these highly rated halls. Boston has 283 cubic feet per person; Benaroya has 280.

Not all successful concert halls are shoe boxes. The highly regarded St. David's Hall of Cardiff, Wales, is an elongated hexagon, tapered in the rear. Segerstrom Hall in Costa Mesa, Calif., is a 2,903-seat multipurpose hall that has a complex seating design of "trays" of different heights, each with their own reflective walls; it's also highly rated by critics.

"Some people think I'm an old-fashioned fogey," Harris says, "for not going with the round hall design, such as Berlin, Denver and San Francisco's Davies Hall (all designed with audience seating at both the front and the back of the stage).

"They're gradually finding out, however, that this design doesn't work as well. Davies had the round part chopped off, and now the acoustics are much better."

The sound is more intimate and clear, and the bass response is greatly improved.

In Seattle, Harris and Reddington are certain those attributes and others will be present right from the opening downbeat in Benaroya Hall.

"At a certain level, it's always a matter of taste," Reddington says. "But I'm completely convinced they'll all agree it's one of the best halls around."

So is Harris.

"I'm a poor gambler," he says, "because I hate to lose. I'm completely confident that the sound will be great in Benaroya Hall."

Melinda Bargreen's phone message number is: 206-464-2321. Her e-mail address is: mbar-new@seatimes.com

--------------------- Acoustical conference ---------------------

The Joint 16th International Congress on Acoustics and the 135th Meeting of the Acoustical Society of America - the largest meeting devoted to the science of acoustics - opens today at the Seattle Sheraton Hotel and Towers and the Westin Seattle Hotel and runs through June 26.

Researchers will discuss the science of Jimi Hendrix's guitar distortion, acoustic surgery, fish love songs and how sonar is being adapted to monitor the world's increasingly depleted fish populations, among other topics.

Registration is steep: $175 to $350. But free information is on the Web at http://www.acoustics.org