Translation of the Süddeutsche Zeitung article “Verblüffendes Wunder”
Published 22 October 2019
Even the shell of Kronberg Academy’s new chamber music hall sounds astonishingly good
As the great violinist Gidon Kremer took to a makeshift stage for the topping out ceremony in the shell of the Casals Forum concert hall and played from the Preludes for Solo Cello by Mieczysław Weinberg that he has transposed for the violin, something extremely unexpected happened. Kremer’s playing was not simply left exposed to the inclemency of a draughty concrete construction in its crudest form, still open on all sides, which blows away all useful impressions of sound. Surprisingly, it actually held its own with credible sonority. Eminent Hungarian pianist András Schiff afterwards marvelled at how the different registers, from the bass frequencies to the treble, can already be so vividly heard, meaning that we really can expect great things when the hall, designed to seat 550 people, is finished in two and half years’ time and is able to display its true acoustic qualities.
The Casals Forum of Kronberg Academy, a prestigious institution where budding top flight musicians from all over the world meet with the greats in their field to attend masterclasses and make music together, will give the small town of Kronberg, situated high in the foothills of the Taunus mountains, one of those rarest of concert halls dedicated solely to chamber music. Adjoining this will be a study centre, likewise under construction, for some thirty students and Kronberg Academy’s administrative staff. Small auditoriums are usually no more than appendages of large concert halls. Exceptions such as Berlin’s Pierre Boulez Saal and the Chamber Music Hall of the Berlin Philharmonie confirm the rule. And yet chamber music, whether for a solo instrument or chamber orchestra, really does need proper venues where it cannot get lost in their magnitude, since otherwise players often find it necessary to force the sound to gain any sort of presence.
The heart of the Kronberg project is, of course, the concert hall, which was designed with close coordination between the architectural firm of Volker Staab and acoustician Martijn Vercammen and his team, the shell of which is now complete. “Friction generates heat,” says the architect smilingly, and Vercammen grins in agreement. The pair needed this to find a productive common ground. Volker Staab explains that he has learnt a great deal, the Casals Forum being his first concert hall. In particular, Vercammen explained to him how acousticians first look to understand a space by how reflective the surfaces are. On first alighting at Kronberg’s train station, for him, reaching this tram terminus with its ugly adjacent car park was like arriving at some unloved Deutsche Bahn railway siding.
Yet the topography of the site was promising. The building plot sits below the town, its Viktoria Park sloping away gently to the west, while to the north the incline breaks into a ledge. Directly next to the train station, the wall of the new hotel building that frames the forum on its eastern side now rises up almost abruptly, thus forming a public square between the concert hall, study centre and hotel. The study centre is the least conspicuous of the three buildings, seemingly slid under the hillside and ultimately to be clad with a green roof which extends the contours of the slope, so to speak. Staab planned the concert hall as a pavilion-style structure that will emerge out of the downward slope of Viktoria Park, thanks especially to its as yet unconstructed roof, whilst towering proudly over the square to the other side. Furthermore, Staab’s concept of openness and transparency has greatly influenced the project, as a belt of glazing circles the auditorium separating the audience seating below from the lobby area above.
Concave wall areas absorb sound, convex ones reflect it extremely well
Consequently, any flâneur or passer-by is able to look in through the window from outside on all that happens in this hall. Watching musicians at work is captivating. The hall invites you to visit, no matter whether there are rehearsals, workshops or concerts taking place.
Staab recounts that, influenced by Berlin’s Chamber Music Hall, he had visualised a vineyard-style auditorium. Raimund Trenkler, however, who founded Kronberg Academy in 1993 and is the tireless initiator of the Casals Forum project, had instead imagined a so-called shoebox design owing to the substantially better acoustic conditions it brings. But the shoebox somehow looked out of place, clumsy even, on the ground plan.
And so, after renewed intervention from Trenkler, the hall’s actual form was ultimately found. A supple space of pleasingly well-structured dimensions with convex and concave curved walls, a hall in which, although a classic positioning of stage-facing-public prevails, the surrounding galleries provide a sense of the magic felt in vineyard-type halls where listeners gather around a central point.
“The acoustics can already be seen and heard in the concrete walls,” explains Vercammen. Because humans have ears on the side of their heads, the way the sound reflects from the walls must help to transport it here. Concave, or inward curving, wall surfaces and recesses absorb sound whilst convex, or outward curving, wall surfaces reflect sound extremely well, according to Vercammen. This is why it was important to achieve the perfect balance between the two within the space. Consequently, all the calculations and measurements also had to be implemented architecturally, which led to friction with the architects, though this now elicits almost gleeful smiles from the two teams at the sight of the striking, now accessible, building that resulted from it, and of course the sound that can already be heard.
For Martijn Vercammen, it was therefore no marvel that Gidon Kremer’s violin was able to create a promising impression of sound even in the building shell. And even if, as with all new, so precisely calculated concert halls, a last remnant of acoustic uncertainty is always possible, this leaves us full of anticipation for the finished hall when it is completed in 2021.
Süddeutsche Zeitung, 22 October 2019
© Süddeutsche Zeitung Content / Dokumentations- und Informationszentrum (DIZ) München GmbH
Translation: Kronberg Academy Foundation