The previous public address system consisted of a single speaker cluster positioned at one end of the facility, providing limited speech intelligibility. Answering the call for complete and intelligible speaker coverage for every seat in the stands, Rutledge Engineering and Acoustic Directions, in conjunction with audio consultants Marshall Day Acoustics, designed a new fully distributed sound system featuring Harman HiQnet protocol technology, BSS Audio, Crown and JBL Professional. Rutledge Engineering was contracted to supply and install the new public address system.
Jands Australia provided the custom JBL cabinets for the upgrade. A total of 164 custom JBL PA speakers were utilized in the massive installation. The speakers were distributed among 55 clusters to cover the arena seating area. Multiple Control 25AVs were placed under balcony, along with a combination of Control 26s and Control 19 in-ceiling subwoofers installed throughout the facility in the function rooms, dining areas and walkways, providing a clear, property-wide PA system.
Audio processing and distribution is handled by a BSS Soundweb London system and the JBL loudspeakers are powered by 128 Crown CTs amplifiers which are located in communications rooms throughout the property. The use of CobraNet between devices facilitates transmission of high quality digital audio on a single network cable. This HiQnet system allows MCG tech staff to configure, control and monitor the entire audio system from remote locations around the facility grounds.
The optical fibre backbone carries all the audio and control required to connect the hundreds of components into a single integrated system. A gigabit Ethernet network runs via the structured optical fibre and Category 6 copper ties between the communication rooms housing all the amplifiers, digital audio processors and network switches, to the two core distribution rooms. Built in redundancy provides an automatic switch in network traffic should any of the trunking cables become severed or an equipment failure should transpire.
Redundancy is also built into the audio system using a CobraNet priority configuration. Two Soundweb London devices performing identical tasks are configured such that should the primary device for the Northern Stand fail, the secondary device for the Southern stand would immediately assume the primary role. This swap-over to the secondary system is seamless and would be unheard by the crowd.
The Soundweb London devices also handle digital audio processing for the entire ground including EQ, compression, delay, gates, ducking, etc as well as EWIS interface and override. CobraNet audio is transmitted directly from the Soundweb London BLU-80 devices to the Crown amplifiers, with Crown USP3/CN PIP cards installed, and also to the Soundweb London BLU-32's, with an analogue output to Crown PIP Lite cards.
In addition, the Soundweb London system is interfaced to the function rooms (in the new Northern Stand only) for EWIS override purposes where they also utilize EQ, crossover and gates as available.
The new system made its successful debut in December 2005 for the Boxing Day Cricket test match. Founded in 1838, the Melbourne Cricket Club, whose membership waiting list exceeds its current member list, has a long and prestigious history. Home to the 1956 Olympics, the MCG expanded its exceptional events resume by hosting the 2006 Commonwealth Games last month.
(Chris Henry)
