Behind the scenes

Photo | Bosch Rexroth AG
Marginal Column

July 2011

 

Sophisticated stage technology built by Rexroth makes the Kodály Concert and Conference Center in Pécs a quick-change artist and an acoustic gem.

 
 

A stone snail that wraps itself around a wooden concert hall. That is how the architects describe the Kodály Concert and Conference Center, dedicated last December in Pécs. This multifunction building was built after this town in southern Hungary was designated as one of the “2010 Cultural Capitals of Europe”. Since that time it won praise from architecture and music aficionados and conference visitors. Bosch Rexroth in Hungary acted as a main contractor and bore project responsibility for the stage equipment that makes concerts and other events possible at all. In joint efforts with specialized Hungarian subcontractors, the local office in Budapest installed a vast array of stage machinery in the building that Russian violinist Maxim Vengerov has proclaimed to be an “architectural Stradivarius”.

In the focus here were multifunctional use of the building as a whole, along with great expectations in regard to the flexibility and acoustics of the hall for concerts and theater. For the companies involved, this contract demanded the highest quality in execution, adhering to the budget, and on-time completion.

A practical up and down

Carefully planned sub-floor machinery, under both the stage and the house, was indispensable for flexible use of the hall. Moving platforms serving as the three-part floor of the orchestra pit can be set at any level between the two extreme positions. They modify the space as required. With the platforms – welded steel latticework structures – the seating capacity can, for instance, be increased from 880 to as much as 999. But they also provide additional design flexibility on the stage. Thus parts of the orchestra – or music instruments like a concert grand piano – can be quickly raised or lowered to various levels to suit the particular performance. Synchronized drive units with an absolute path measurement system ensure safe and gentle raising and lowering, working in concert with Serapid Linklift rigid chain actuators and double-braked motors.

Flexible tilt

Photo | Bosch Rexroth AG

The hall.

 

The concert hall is transformed into a ballroom or conference space at push-button command. The first third of the steeply raked floor can be tilted into the horizontal within one and a half minutes while the rows of seats disappear below the floor. This tilting floor surface, about 185 square meters in size, rests on special rotating trestles at the end toward the stage. Hydraulic cylinders raise and lower this plate at its rear edge. Support feet stabilize the floor beneath the audience and a series of gas-loaded springs at the center of the plate protects the steel structure against deformation while it is being raised. Proportional valves control the hydraulic cylinders and Rexroth HNC 100 axis control make for closely regulated synchronicity.

PROFIBUS connectors transmit status and malfunction reports and motion commands to and from the control center. The HNC software continuously monitors the hardware components and motion parameters – such as the shifting speed or the software-regulated limit position – while cable-type linear transducers precisely gauge the cylinders’ positions.

World-class tonal quality

Photo | Bosch Rexroth AG

The machinery in the fly.

 

But the quality of the hall can also be heard. Comparisons of acoustic parameters make it clear that the concert hall in Pécs need not fear international comparison. Seven suspended acoustic reflectors above the orchestra stage can be tilted so that the acoustic situation in the hall is always perfectly matched to the orchestra’s seating arrangement. Settings that are found to be good can be stored and called up again whenever needed.

Superior audio recordings are made possible with twenty-four microphones that can be regulated individually and are positioned above the stage and the audience seating area. They are moved by way of a self-locking screw drive and a three-phase electric motor. The electric control box with the drive’s control elements are installed at the drive casing. The system can be programmed so that each microphone automatically moves into the desired position once the program corresponding to a specific configuration has been called up.

When the curtain rises and the first notes of a symphony fill the Kodály Concert Hall, then the sophisticated technology is invisible to the audience. But it can be experienced: A superior view from every seat, diverse stage and orchestra configurations, and unforgettable listening pleasure testify to the inner values, tucked away behind the scenes.