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Distributed PA On A Fiber Backbone

Australia's Olympic Park, home to the 2000 Summer Games, showcases the future applications of large-scale distributed systems over a fiber optic backbone.

While the Sydney 2000 Summer Olympic Games are fast becoming a pleasant memory, digital audio and routing technology implemented for the event portends significant and lasting implications.

Perhaps nowhere is this more in evidence than at the Olympic Park campus, which features an extensive public address system running on a fiber-optic backbone, expected to be in operation for at least another decade. Located in Homebush Bay, often referred to as the demographic heart of Sydney, the campus forms a 2.5km circle surround the Olympic Stadium and it includes a dozen other sporting and exhibition venues developed for the games.

From the outset, the campus was designated to remain a permanent fixture, with extensive residential, recreational and retail areas complimenting the athletic facilities. A commercial center for high-tech industry will also emerge, further revitalizing an area that previously had been, among other things, a naval armaments depot and waste dump.

As one of Australia’s premier design and integration firms, The PA People were already busy implementing a complex distributed sound system at the 110,000-seat stadium when summoned by Olympic organizers to have a look at the campus-wide PA system. Chris Dodds, managing director of The PA People, notes that although the fiber optic pipeline had been established to transport audio, lighting and CCTV, along with commensurate control data for each, serious concerns about the audio segment had arisen.

“The client conceived what is best described as a ‘mass transit’-style public address system that would also allow entry of localized source devices to be introduced on the fiber network, with this input distributed to selected zones,” Dodds explains. An attempt to attain the first phase of the project by the previous contracting firm can be quickly summed up as analog audio modulated on the fiber system with limited routing to zones via a single 16-input by 16-output matrix, falling short of expectations in terms of performance quality, flexibility and functionality. This direction scrapped, organizers turned to ARUP Acoustics , a leading Australia-based electro-acoutics firm, as well as The PA People a scant 20 weeks prior to opening ceremonies for a more effective approach.

“Our development of a complex control and routing scenario at the stadium, easy in operation, attracted the interest of the client and they wanted us to create something similar for the campus-wide system,” Dodds says. “We were merging technologies such as Peavey MediaMatrix, Peak Audio CobraNet and Crown IQ with proprietary digital designs from Creative Audio, our sister company, into a comprehensive front-end package. It was fairly obvious that something like this could be adapted quickly for the campus.”

The revised bid on the project was broken down into bite-sized chunks, with four main phases.

  • Phase one: supply and install MediaMatrix and CobraNet hardware and software to replace the existing matrix;
  • Phase two: new Crown amplifiers outfitted with CobraNet-ready Creative Audio modules to drive JBL loudspeakers in existing areas previously installed;
  • Phase three: a new control and messaging package to be developed and deployed;
  • Phase four: the balance of JBL loudspeakers and Crown amplifiers with Creative Audio modules to be installed.

Chosen to design and implement all four phases under the direction of ARUP Acoustics, The PA People installed speakers in more than 80 individual audio areas throughout the campus. An extensive set of paging priorities and hierarchies would supply live system-wide paging, live paging to designated zones, pre-recorded message and background music, again system-wide or by select zones, and most notably, local inputs and wireless microphone system inputs scattered throughout the campus, available for localized entertainment, presentations and paging.

Open Platform
In basic overview, the system can be described as a central control front-end networked with several distributed “nodes” via the fiber backbone. But in reality it’s a bit more complicated than that. First, this project marks the first real-world application of Peak Audio’s implementation of Simple Network Management Protocol (SNMP) for addressing all CobraNet devices on the network.

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