Built for the 2004 Men’s World Ice Hockey Championships, the O2 Arena is home to the HC Slavia Praha and HC Lev Praha ice hockey teams and also hosts a range of other sporting and corporate events and concerts. Capacity-wise, its audience record stands at nearly 19,000 fans for a Madonna concert.
Formerly known as the Sazka Arena, the venue needed to replace its existing PA system installed 10 years ago. The original point source system was, by the venue’s own admission, under-specified and under-powered. Attempts had been made to adapt the system but the loudspeakers were already being pushed to their limit, and nearly a third of them had failed. Informed by 10 years’ experience of operating a large arena, the team decided it was time for a new system.
The brief required a complete new PA/VA system to provide information and emergency announcements as well as music. The new system needed to integrate easily into the Arena’s existing systems, and to represent good value for money.
“We looked at the best technology around the world,” says Jan Plihal, head of media technology at the Arena. “After much research and negotiation, we narrowed it down first to four and then finally to two possible solutions.”
NEXO was actually on the Arena’s radar when the older system was installed a decade ago. At the time, Plihal met with NEXO’s R&D director Francois Deffarges and was impressed by the company’s philosophy of line array, even back in 2004. However there wasn’t enough space in the arena roof then to install NEXO’s GEO S8 product.
Today, a new GEO S12-ST system has been supplied and installed by NEXO’s Czech distributor MusicData, using a total of 72x GEO S12-ST with 24x RS18 subs. The GEO S12-ST cabinets are flown from a central ‘cube’, carrying large screens on each side, which descends from the ceiling for sporting, congresses and corporate events. When the cube is lowered, it is still 24 metres from cabinet to the floor, and this is where the GEO S12-ST’s long-throw capability comes into its own. The compact 2-way ST cabinets have been developed from the standard GEO S12 design offering the high SPL and enhanced speech intelligibility required for stadium and arena applications.
The 24x RS18 subs – also flown – enhance events such as motor sports, BMX championships and the Davis and Federation Cup tennis matches. “These days, events like this are more and more a show,” says Plihal. “It’s not just about the sports, we have to think about commercials as well.” Although a typical level for an ice hockey match is 90-94dBA, an SPL of 106dBA is possible in the Arena. The system is driven by 16x NXAMP4x4 TDControllers situated in rack cases in the roof, providing 256KW of power.
The Arena houses a staggering 900 kilometres of cabling to carry its entertainment technology data. Newly-installed is a fibre optic cabling infrastructure to carry a EtherSound ring network for the audio. Auvitran network devices deliver the signal from control room to racks with full double redundancy, while an option to switch to analogue offers even more backup. If any amplifier should fail, the system will automatically switch to another one.
As the Arena team requires a degree of control over every element of the system, MusicData sat down with Plihal to design a custom network interface, which runs on iPads connected to Wi-Fi. This displays highly visual information required for day-to-day operation, such as the ability to switch on and off each of the Arena’s 24 different zones set over three levels including the pitch. The interface also displays the voltage on the output of the amps, giving a complete visualisation of the signal travelling through the system.
The O2’s new PA system perfectly meets Plihal’s motto, “to be prepared for all”. “We have one of the best arena acoustics, with a reverb time of less than two seconds,” he says. “The seats are acoustically treated, so there is little difference to the sound whether the venue is empty or full. The NEXO cabinets have been positioned to minimise the small reverberation problems we get from the glass-fronted VIP boxes. We expect excellent audio for speech and music, and the implementation of the emergency system is the most important thing.”
The Prague O2 Arena is finally enjoying a PA system with a clear and powerful sound that does justice to the exciting events staged there.