The shape of perfect acoustics
WHEN plans were made for a new concert hall in Hamburg, Germany, local leaders placed acoustical refinement high on their list of priorities. But they also wanted an auditorium that was more “democratic” than traditional concert halls, where “good seats” in the front are more valued than “bad seats” at the back.
“A hall without hierarchy” was an explicit goal of the Hamburg authorities.
The architects looked for inspiration not just from classic modernist halls, but from contemporary stadium design as well. But this raised a formidable challenge: How to predict the hall’s response acoustically? Yasuhisa Toyota, an acoustician who has had success designing concert halls, was hired to deal with this building’s many acoustical challenges.
Among them: The concert hall is set in the middle of a noisy, bustling harbour, where ships blow horns loud enough to be heard through walls; and the auditorium isn’t the only inhabitant of the building, which also includes a hotel and residential condos. So the hall needed to be insulated not just from noise outside, but from becoming a noise nuisance to its neighbours.
So the music hall was insulated from the larger structure by “shock absorbers” that help minimise the transmission of sound into and out of the space. And inside, it is covered with what locals call the “white skin”. This is a continuous surface of gypsum-fibre panels, each one with its own unique pattern of sharp peaks and declivities. The irregularity of the surface helps diffuse sound, just as the ornamented wood and plaster of old 19th century concert halls did.
The shape of the white skin’s pattern is an echo of the roof line of the building – form follows function in this case – though each peak of the skin’s texture is different from the others. The acoustics are also regulated by a large reflector, which descends into the vertical space like a dangling mushroom.
The results? Some critics find the space cold and clinical. But it has great clarity and presence, and the carefully calibrated decay of sound also creates a sense of warmth. The white skin is also lovely to look at, like some kind of luxury fabric stretched taut over the space, full of visual interest, but never distracting.
During performances of Beethoven in March, the tiniest sound from the stage was clearly audible as was any sound, including whispers and coughing from the audience. But the real test came with details of orchestration, which were perfectly audible.
This is the rare hall in which you notice which mallet the timpani player is using or when an oboe joins a bassoon. The strings sections are clearly distinguished, and when the first and second violins exchange ideas, you hear the drama spatially. – The Washington Post