Built in 1966, de Doelen today operates as a foundation and is considered acoustically to be one of the world's finest modern concert halls. With the Rotterdam Philharmonic Orchestra also resident, the pressure on head technicians Frank van Donkersgoed and Bram Ruitenbeek to remain sensitive to the building parameters while specifying the system that would best meet the requirements of an expanding programme, was paramount.
The main concert hall seats 2,200 people in an auditorium measuring 60m x 30m, while the 700-seat congress centre is housed in a new section of the building constructed in 1997. The management wanted to advance certain elements - notably the stage, infrared provision and the loudspeaker system; in 2003 the idea was rubber-stamped by the complex's enterprising managing directors, G. Oostvogel and A.M. Vliegenthart, with the work to begin in 2005.
The hall had been running off a centre cluster PA - which Frank van Donkersgoed says had been designed principally for speech amplification, but was often misused as part of a PA system (in combination with some delay speakers and heavy EQ). "This worked OK for concerts that needed a minimum of amplification - and when we needed more, we would simply rent in a system," he says.
The criteria was to aim for 105dB on each seat - with a coverage of 80% of the seating with ±3dB (and ±6dB over the remaining 20%). "We wanted a pretty high sound pressure level but we also had to meet the requirements for speech intelligibility," says Frank.
The venue's ceiling has both an architectural and acoustic function in respect of the reverberation times on the low frequencies. However, in 2009 the ceiling design is likely to change (exposing the 4m that exists in the void above) to facilitate the installation of a new lighting truss. "We want the architectural and acoustical properties to become exactly the same, and are experimenting with new ideas to bring it more up-to-date."
These reasons, along with the general aesthetic, presented a compelling case for a mini line array solution. "There were arguments to do with SPLs and reverberation time which suggested a larger system would have been counter-productive. In a concert hall with reverb time of up to two seconds this will be reduced with a smaller line array," believes Frank. He put his theory to acoustic advisers Peutz (who also consulted on the Royal Albert Hall acoustics), who agreed.
Five internationally-recognised brands were put forward - with one prerequisite. "It was important that the house technicians had a system that they liked - in audio engineering that is vital."
The evaluation was rigorous. The five brands were reduced to three with each given the chance to operate in real world conditions in the main hall. "We wanted to give them a chance to do a concert here prior to the shoot-out, and we also visited sites in Holland for remote evaluation," says the venue's head technician.
In the case of Martin Audio, Frank listened to the W8LC installed by TM Audio at Oosterpoort in Groningen. TM Audio's audio consultant, Reinier Bruijns was among the rental consultants who became increasingly involved with the project as the Evaluation drew to a close. He remembers: "There were two rounds in the shoot-out and we were given the opportunity to make system adjustments between each. Extra trussing was put in for the occasion and a lot of trouble was taken to get the systems up correctly."
BV Oorzaak organised the audio testing playing various selections on CD in front of an audience of 80. But de Doelen also wanted performance onstage to show off the live amplification. The second test involved 20 qualified technical perso
