When the City of Manchester Stadium heralds the start of the XVII Commonwealth Games on July 25, public information will be broadcast to the maximum 38,000-capacity seating via a sophisticated new sound system.Built by contractor Laing, Arup’s design of the £77m stadium is based on an eight-mast and cable structure, ensuring that all seats have uninterrupted views of the pitch. Every part of the stadium structure is used to support the 600-ton undulating roof which covers every seat.

Its acoustics have been cleverly tuned to enhance the crowd noise by using the underside of the roof. Arup Acoustics has provided this design service, as well as the building acoustics and overall sound system design, in addition to an environmental noise impact assessment on residences in close proximity to the site.

Blackburn-based Romers successfully tendered for the entire Public Address/Voice Alarm installation contract, drawing on the TOA catalogue to fulfil Arup’s document specification. John Caton, managing director of Romers revealed that this is the largest single project the company has ever undertaken. "The stipulation was that we had to use a branded speaker for the speech reinforcement, and TOA MS1s fully meet the requirements," explained Caton, adding that the enclosure is also in use at Manchester City’s Maine Road facility - and the football club insisted on continuity in the new ground.

The TOA MS1 speaker was designed for sports stadia use and incorporates their touring driver - the twin-magnet sub-woofer (2 x 12" and horn) - with the 2" compression driver looking after the HF. TOA supplied EASE data, enabling the designs to be fully optimized, and the wide dispersion, heavy midband characteristics of the 56 distributed MS1 to be fully utilized.

Fed by emergency/mic and programme sources (via the DJ station) the system is distributed to four terrace zones. Run in biamped mode, two lines of MS-1s respectively feed the upper and lower tiers, with TOA VP-1240 amplifiers powering the top tiers.

Thus in the north and south stands, the flares are rotated to alter the dispersion characteristics. In order to accommodate that flexibility, TOA needed to enlarge the enclosures, while specially-manufactured brackets accommodate the precision angling of the boxes. The temporary stand is served by 12 90° x 40° constant directivity horns.

All the HF signal is carried through mineral-insulated cable while the bottom end runs through 4mm cable. Each speaker line has its own channel assigned to TOA’s DP-0206 DSP device - a 2-in/6-out expandable DSP engine which is entirely reconfigurable. John Caton has been a big fan of the DP-0206 since its launch. "We don’t need to look for alternatives because the human interface is just so easy," he says, "and it looks and sounds analogue. We can put EQ and compression on the input - but because of its expandable reconfigurability we can also have it on the output." With so many 47U racks housing the raw amplifier power, any saving of real estate is a blessing, and John Caton acknowledges that using conventional analogue devices, he says, would require another processing rack.

The publication of Lord Justice Taylor’s report following the Hillsborough tragedy led to the publication of the Green Guide, by which stadium specialists such as Romers now have to conform. John Caton’s company will provide three days’ training on a system on which the only accessible settings are on the mixing desk (the DP-0206 presets being safely locked away).

As to the future, within days of the Games’ closing ceremony on August 4, the temporary stand at the northern end of the stadium will be pulled down and a permanent structure built to adjoin the rest of the stadium. The athletics track will be removed, and replaced by seating, bringing fans as close to the action as possible and raising the capacity to 48,500. The Stadium will then become the permanent home to Manchester City FC, commencing w


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