Rich and warm acoustics: the converted Tonhalle Maag is a convincing, high-class interim venue
During the renovation and refurbishment of the historic Tonhalle in Zurich, the Tonhalle Orchestra will perform in a former machine factory
For the next three years as of the season start on September 27, 2017, the Zurich Tonhalle Orchestra (founded in 1868) will perform in the Tonhalle Maag on the premises of the Maag machine factory in Zurich West. There, the local Spillmann Echsle architects together with the Müller-BBM acousticians integrated a concert hall into the previous event hall. This new hall shall serve as a high-class interim venue during the entire refurbishment period of the Tonhalle which is appreciated worldwide for its excellent acoustics. All reconstruction and installation works were completed in just 10 months. The budget of in total ten million Swiss francs was met, six million francs thereof were dedicated to the concert hall.
The concert hall as a traditional rectangular hall
The interim venue is a traditional rectangular hall which was installed inside the existing hall. The acoustic experts Karlheinz Müller and Michael Wahl of Müller-BBM describe the existing volume as “quite limited” for a large orchestra sound – yet, the interim venue is very similar to the Tonhalle. With regard to the acoustic measures and the hall design, particular challenges resulted from this situation: for instance, many right angles in the hall were modified and turned into well resonating acoustic elements, spruce was used for the wall and ceiling surfaces and oak panels for the floor. The ceiling elements are filigree, diffusely structured and fully adjustable “so that they literally 'welcome' the sound”, according to the acousticians.
A high-class temporary venue, flexible panels and millions of holes
A total of 70 wooden panels suspended from the ceiling serve for distributing sound in the hall, alone 24 of them are suspended above the podium. In the podium area, they are somewhat convexly shaped and can be flexibly adjusted. After the first orchestra rehearsals, the positioning of the panels was changed again to further optimize the reverberation and scattering of sound. In addition, the electro-acoustic room enhancement system Vivace of MBBM Acoustic Solutions GmbH is installed and makes it possible to fine-tune the sound for different kinds of events.
The concert hall accommodates an audience of 1,224 on mobile, velvet-covered seats; 784 in the stalls and 440 on the balcony. To reduce the ventilation noise, there are more than two million tapered holes in the floor. A highly sound insulating separating wall protects the “Tonhalle Maag” acoustically from the adjacent event area.
The last fine-tuning and refined sound
As always shortly before an opening, numerous acoustic tests and simulations are performed in the occupied and unoccupied hall. On the podium, various seating arrangements are tested for different orchestra settings. A dodecahedron loudspeaker produces sine tones in the frequency range between 50 and 12,000 Hz covering an interval of eight octaves. Six microphones in the hall transmit the results to a computer.
The declared aim of all parties involved was and still is that the acoustic conditions in the interim venue do not differ too much from those in the venerable Tonhalle. The result can be experienced for the first time on September 27, 2017, when the Tonhalle Orchestra plays a festive season opening concert with the viola concert of the Australian Brett Dean and with Beethoven’s Ninth Symphony including the “Ode to Joy”.
The inauguration ceremony of the interim venue takes place on September 30, 2017.