Independently specified, the tender involved a four-way shoot out between different proprietary systems. NEXO won the contract with a Geo line array system, featuring 18 clusters of 4 x S-805s to cover the large concrete and asphalt Concourse, which covers the underground parking facilities and is home to four Villages of sub-attractions. The 1,750,000 sports and music fans who attend events at Stade de France can visit Animations for video game action, buy apparel and gear at the Boutique Officielle, get refreshments at Kiosque Coca-Cola, or get directions at Point info. Each Village occupies a small square about 20m on each side, attracting customers from a quadrant of the entrance apron, which surrounds the exterior of the stadium.
The NEXO system at Stade de France uses a short curved vertical array or cluster of GEO S805 loudspeakers. Each of these devices is a two-way system with a passive internal crossover network dividing an 8 inch vented woofer and a 1-inch compression driver. The driver is loaded on a patented GEO wavesource with 5° vertical and 80° horizontal coverage. This unusual pattern is achieved by using an hyperboloid acoustical mirror to reflect energy from the compression driver into the 5° arc. In the horizontal plane, the wavesource operates as a diffraction slot with the 80° pattern being created by the flare at the slot’s exit. A removable set of flanges can alter the horizontal dispersion to 120° if desired. Both the acoustical mirror and the diffraction slot are patented by NEXO.
Working with SSE Melpomen of Paris, NEXO used this unique array element to design short curved vertical arrays of four elements. By varying the angle between adjacent cabinets from the top to the bottom, the designers were able to deliver equal acoustic power (and therefore equal SPL) to both near and distant sections of the listening area.
(Ruth Rossington)
