Xi’an Olympic Sports Stadium install snags EZ Pro an Inavation Award

This year EZ Pro topped the Inavation Awards Leisure and Entertainment category with a sports centre installation of epic proportions. Take a look at what went into this award-winning project.

When Xi’an, the capital city of the Chinese province of Shaanxi, decided to expand its leisure and sports facilities, an ambitious plan encompassing three massive sports complexes was drawn up. And with the 14th National Games of China scheduled to be held in the stadium complex this September, a tough deadline was set in stone.

Distributor and integrator EZ Pro answered an open tender and was drafted in to handle the ¥ 30 million (nearly €4 million) audio installation across the 866,667 square metre site, delivering to exacting standards in just 14 months.

Xi’an Olympic Sports Stadium install snags EZ Pro an Inavation Award

At a riverside location, the complex encompasses three zones: a main stadium with 60,000 seats, a gymnasium with 18,000 seats, and an aquatic centre with 4,000 seats.

EZ Pro says reliability was the number one concern for the audio systems across all three zones. The integrator therefore started with a vast fibre optic network, setting up redundant signal paths within the network architecture to handle seamless signal switching, remote monitoring, as well as far-end command and control.

Powersoft amplifiers were selected to help meet requirements for redundancy, and provide powerful DSP processing, while Powersoft’s ArmoníaPlus software helped deliver remote control capabilities.

Xi’an Olympic Sports Stadium install snags EZ Pro an Inavation Award

Control and power management functions were centralised and stadium staff can quickly switch audio scenarios and modes, as well as remotely turn equipment on and off to save power. Maintenance personnel can also monitor the states, temperatures, and impedances of devices.

In addition to Powersoft, a combination of equipment from EAW, Allen & Heath, Symetrix and Furman was selected.

Speech intelligibility was paramount to the success of the project. EZ Pro approached each zone separately, doing extensive measuring and modelling of the venues’ sizes and acoustic conditions. Distributed layoutsXi’an Olympic Sports Stadium install snags EZ Pro an Inavation Award were selected for the stadium and aquatics centre, while the gymnasium makes use of a centralised layout.

Jiang Yongjun, the technical manager of EZ Pro’s Xi'an office, says: “The initial design of the audio system has centralised distribution for the line array but for the actual installation there are places where we decided to go with distributed installation together with point source speakers. This also meant that the total number of loudspeakers deployed changed as well.”

Microphone and audio source signals from the venues’ integrated stage boxes, functional rooms and control rooms flow to audio jumper racks and mic/line signal distributors, which are connected to interface boxes of the main and redundant mixers in amplification rooms. After A/D conversion, the signals are transmitted to specific sub-control rooms through optical fibre. Main signals go directly into amplifiers with Dante cards before feeding loudspeaker systems nearby. This process is designed to minimise A/D and D/A conversions, ensuring signal quality. Standby signals go into amps through analogue inputs after D/A conversion within signal stage boxes. The signals are then fed into loudspeaker systems standby. Hot backup is achieved via detection and auto switch by digital amps dealing with digital and analogue signals.

EZ Pro had to navigate some tricky areas in the stadium. The integrator hung loudspeakers from the catwalk above the audience area, but were limited by the weight they could add to that structure. Opting for high powered, lightweight options, EZ Pro installed 136 waterproof EAW loudspeakers including 112 MKD1064-WP 2-way full range loudspeakers, 16 QX364-WP two-way trapezoidal enclosures and 8 VFM129i passive two-way enclosures. Speakers are powered by 34 Powersoft Quattrocanali 4804 DSP+Dante amplifiers. Three Allen & Heath digital mixers were also delivered; a dLive C3500, an Avantis and an SQ-5.

Xi’an Olympic Sports Stadium install snags EZ Pro an Inavation Award

Over in the diamond shaped gymnasium, EZ Pro had to deal with a reverberation time up to 3.5 seconds. Thirty-five degree bleachers surround the centre stage and the venue had be able to quickly pivot between hosting basketball or ice hockey, placing further pressure on the sound system requirements.

EZ Pro decided on EAW’s Radius line array that offered more direct sound and less diffusion to the bleachers and therefore improved speech intelligibility. The speakers have built in infrared sensors and accelerators and can execute self-detection and optimisation in real-time.

Xi’an Olympic Sports Stadium install snags EZ Pro an Inavation Award

Fifty-two EAW loudspeakers and 18 RSX18F self-powered subwoofers were deployed in the gymnasium, along with three Allen & Heath digital mixers: a dLive C3500, an SQ-6 and an SQ-5. Digital signal processing was handled with two Symetrix Radius NX 12x8 and a Powersoft Quattrocanali 4804 DSP+Dante amplifier was installed.

Finally, in the aquatics centre, 24 EAW loudspeakers and 6 subwoofers (8 MK5364i passive 2-way full-range loudspeakers,12 MK5394i passive 2-way full-range loudspeakers,6 SB180zP subwoofers,4 VFM129i passive two-way enclosures) were installed. Three Allen & Heath digital mixers; two SQ-6s and an SQ-5 were deployed. Eight Powersoft Quattrocanali amplifiers were installed alongside two Symetrix Radius NX digital processors.

Xi’an Olympic Sports Stadium install snags EZ Pro an Inavation Award

Across all venues, each loudspeaker is fed by an independent channel in order to offer full control of coverage, while reducing interference from undesired reflections and ensuring the number one goal of speech intelligibility was met.

The tight schedule was especially tough when it came to loudspeaker installation. “We only had seven days to complete the installation,” says Yongjun. “To finish the installation we broke the work into batches and assigned extra manpower and other workers that work overtime to make sure the installation be completed in time.”

Zhou Jun, chief technical engineer of the stadium project, says high standards were demanded of the technical performance of the audio systems. “The schedule was pressing, yet the sound system installation and commission were finished on time thanks to EZ Pro’s efforts,” he says.

Xi’an Olympic Sports Stadium install snags EZ Pro an Inavation Award

The stadium has hosted some small-scale sporting events as test runs and this September it will host the opening and closing ceremonies of China’s 14th National Games, while all the venues will be used for the event’s various sports competitions.

But the complex was built with longevity, and therefore flexibility to host a range of events, in mind. Yongjun says: “Flexibility was very important, and we took many steps to ensure that it was present in the audio system.

“Each loudspeaker in this project has independent DSP amplifier channels so we can quickly adjust the loudspeakers’ performance according to the demands and according to different kinds of activities. Secondly, we reserved a large number of interfaces for the other equipment. So, we can quickly bring in the other equipment into the existing sound system to achieve to achieve signal exchange and signal switching. And lastly, the digital mixers in this audio system have separate racks. So, when the activities demand it we can move the mixer control interface out of the control room to the position it needs to be.”

Tech Spec

Allen & Heath dLive C3500, Avantis, SQ-5 and SQ-6 digital mixers
EAW MKD and VF series loudspeakers, Radius line arrays and SB series subwoofers
Furman CN-3600SE smart sequencing power conditioners
Powersoft Quattrocanali 4804 DSP+Dante amplifiers and ArmoníaPlus software
Symetrix Radius NX digital signal processors

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