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 awardwinning 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 nearly USD 4.75 million (RMB 30 million) audio installation across the 866,667 square metres site, delivering to exacting standards in just 14 months.
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 was selected as the integrator for the project, tasked with delivering audio systems to get the stadium up and running. Jiang Yongjun, the technical manager of EZ Pro’s Xi’an office, details: “This was an open tender and EZ Pro won this project after negotiations, inspection, investigation and due diligence on the part of the client.”
Mei Hong, senior marketing manager at EZ Pro, adds: “I think one of the main reasons EZ Pro was selected for this project is the fact that we are the exclusive distributor for many world-famous brands including EAW, Allen & Heath, Powersoft, Symmetrix and Furman etc. So, that provides EZ Pro the ability to integrate all these brands to provide a versatile and stable system that is needed by stadiums. Secondly, EZ Pro can provide a total solution for sports venues from detailed design, product selection, installation, to commissioning and tuning. We have various skilled technicians, and we also have a local branch office in Xi’an. This means we can provide very quick response and technical support for the whole project.”
Designing the systems to be deployed was not the remit of EZ Pro but the integrator was heard when it came to amendments as Jiang details: “The project was designed by a third-party consultant and after the open tender we were appointed as the integrator for the fulfilment of this project and of course from there the design was developed more and it evolved. No design can exactly match the actual project so when we had something that needed to change we collaborated and negotiated with the designers and with the consultant and all the parties to determine what would be the best course of action.”
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.
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 layouts were selected for the stadium and aquatics centre, while the gymnasium makes use of a centralised layout.
Jiang says: “The initial design of the audio system had 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 was 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. Over in the diamond shaped gymnasium, EZ Pro had to deal with a reverberation time up to 3.5 seconds. Thirty-five-degrees bleachers surround the centre stage and the venue had to 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.
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 six subwoofers (8 MK5364i passive 2-way full-range loudspeakers, 12 MK5394i passive 2-way full-range loudspeakers, six SB180zP subwoofers and four 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. 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.
Challenges for a project of such scale are par for the course. Working with multiple parties together can cause friction but Jiang says this was not a flashpoint: “The client had a professional team responsible for this project and whenever we had any questions, they would help us and discuss the problems and answer our questions to make sure the project went smoothly.”
The deadline set in stone however caused a time crunch as Jiang adds: “The time for the whole loudspeaker installation was very tight and we only had seven days to complete installation. So, to finish the installation we broke the work into batches and assigned extra manpower and other workers to work overtime to make sure the installation could be completed in time. Also, the installation process was a challenge. We had to determine the way to install the loudspeakers at the specific points as well as the rest of the equipment. But I can say that due to the efforts of our team the installation was successfully 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.”
Jiang 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 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.”
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.
Jiang concludes: “Our engineers have experienced the sound in the stadium, and we think the sound is excellent. High and low frequency response in particular is excellent. Because of how the sound reinforcement system has been designed and installed, we can choose how many loudspeakers we need to turn on which means we can ‘switch’ the loudspeaker positions to optimise the performance for the event. The whole system is controlled which means that the sound experience is great every time.”