Renovating a famous concert hall is delicate business. The patrons, music critics, and musicians who revere it each have their own memories about the warmth and depth of the sound. The hall is sacred ground to them.
Concert halls are the air-space into which live music expands and rebounds, and musicians and critics set great store by particular spaces, such as New York's Carnegie Hall and Boston's Symphony Hall and Jordan Hall at the New England Conservatory of Music (NEC).
''Musicians don't like playing in a 'dry' hall,'' says NEC president Laurence Lesser, who is a cellist. He defines a dry hall as a place where the sound stops where it is played - at the musicians. In a good hall ''you have a bottom to the sound,'' he says, ''a clarity, and an ability for the musicians to hear one another.''
People value such halls so highly that any tampering of the physical space often calls up dire predictions about what may happen to the trademark sound.
That's exactly what occurred two weeks ago at the reopening of the restored Jordan Hall. Critics' pens were poised to write that the facility had not come through the restoration unscathed.
The hall was built in 1903 by Wheelwright and Haven, and is about a decade younger than Boston's Symphony Hall and 12 years younger than Carnegie Hall. But Jordan Hall, which has hosted such notable performers as Marian Anderson, Leonard Bernstein, Pablo Casals, Aaron Copland, and Isaac Stern, was a grande dame in need of a makeover. Ninety years of dust had accumulated, the seats were rickety, and the hall's lack of air conditioning made it uncomfortable.
Jordan Hall is intended to be a performing space inside a school, and the NEC's classrooms and offices enfold the hall itself. (NEC was designated a National Historic Landmark in 1994.) Each of its 1,000 seats is remarkably close to the stage. The conservatory campaigned to raise $25 million for scholarships, projects, and operating funds, out of which $8.2 million was budgeted for Jordan Hall's restoration. The work began in summer and was completed six months later.
Mr. Lesser and his colleagues were determined that no structural changes would be made that could interfere with the hall's acoustics. NEC brought in architect Ann Beha and acoustician R. Lawrence Kirkegaard (who also consulted on post-1986 restoration adjustments to Carnegie Hall.)
Jordan Hall's gleaming new presence was displayed at a coming-out party on Oct. 27. The hall looks spectacular. Every surface has been cleaned and renewed. Plaster repaired. Gold leaf restored. The feeling of being in a dark, wooden cave is gone. Restorers uncovered the original color scheme - an off-white for the plaster ceiling and a jade-green for the arch over the stage. The air conditioning is noiseless. Seats are comfortable.
So what's the problem? For some people, the music doesn't resonate in the hall as it used to. Critics pointed out a brightness and harshness to the sound that hadn't been there. A pianist who has played in Jordan Hall, and who was present at the reopening concert, said that while it was too soon to judge, a certain ''bright'' quality did seem present.
''Has the sound changed?'' Lesser asks rhetorically. ''Probably. A certain amount of loosening up [of the hall] needs to happen. Perhaps a few subtle small changes will be made.'' But, he adds, musicans must make adjustments to playing in the restored hall.
How does he feel about the criticism?
''People are very possessive of their tonal memories,'' Lesser says. ''This talk about the acoustics is wonderful because it means people care.''
It's not easy for a layperson to fathom the arcane business of acoustics. Perhaps a crude analogy would help. For anyone who has hummed or sung in the shower, you know that the tile and glass door, because of their hard surfaces, allow the sound to reverberate so you get a bigger, more echoey sound. But if you drop a ceramic soap dish, the noise can hurt your ears. If you hang towels on all sides, the sound would be absorbed.
Halls work in something of the same way. Every piece of wood paneling, every chair back, every plastered column reflects a certain amount of sound. Cloth baffles, curtains, upholstery, carpeting, and people soak up some of it. If there's not enough absorbent material, the higher frequencies in the music become more pronounced, and the sound is considered ''bright.''
Acoustic consultant Kirkegaard says that even repainting can change the acoustics. In Jordan Hall's case, the old paint had a ''superficial porosity'' that helped absorb high frequencies. He says that he recommended slight fixes to some surfaces in the hall at the start of restoration, which were turned down by the NEC out of concern that nothing be altered.
''If we were patient enough to wait another 75 years,'' Kirkegaard says, the sound would be exactly what it was before restoration. The implication being that minor acoustic changes - 1/16 in. of felt fabric, for example, applied to surfaces that are contributing to the stridency - could bring Jordan Hall more closely in line with its pre-restoration sound.
To explain the challenge of Jordan Hall's post-restoration acoustics, Kirkegaard likens it to ''turning up the treble on your stereo, but to the extent that you also get some echo and confusion.''
There was echo and confusion of a different sort after Carnegie Hall's renovation in 1986, when critics complained that music played there had lost its characteristic warmth. A rumor spread that concrete had been added to support the stage floor.
Carnegie Hall's management denied the reports of concrete. Recently, during work to correct warping of the wooden stage floor, a sublevel of concrete varying from 1 to 4 inches was in fact found. Confusion still surrounds the issue of when and why the concrete was put in, and who knew about it. (The concrete was removed.)
Jordan Hall's restoration is a reminder that, as Lesser says, ''playing music in a hall is an organic, living thing.''
Perhaps it's comforting that not everyone hears sound the same way.