Trevor Peters of Matrix says: "The Coca Cola dome near Johannesburg enjoys a less than favorable reputation for its acoustic characteristics. The space itself is a nightmare in that it is exceptionally reverberant. Furthermore, the domed shape of the venue leads to summing and cancellations dependant of the sound level and listening position. We were very excited to be involved in this event, as it presented us with an opportunity to use the largest Alcons line-array system assembled in the country to date in an attempt to 'tame the Dome'."
The decision was made to use 48 units of Alcons LR16 compact ribbon line-array, 16 units LR16B line-array bass and 12 units of BF362 subwoofers, all powered by Alcons ALC controller-amps. This four-way system was flown in two arrays (with subwoofers ground-stacked) left and right to cover the entire downstairs area including the bleachers, while 12 LR14 ultra-compact ribbon line-array units were flown in four drops of three to cover the upstairs bleachers. The main system with the Real-90 horizontal coverage was projected to offer smooth coverage of the floor area without any major reflections off the sides of the venue.
In the simulations in the Alcons Ribbon Calculator (ARC), throw to the back of the venue showed a flat SPL with 1dB difference from front to rear (the diameter of the Dome is more than 120m/360ft).
Marius Marais, FOH sound engineer for the event, said: "After we took care of the 'bass-drone' we experienced in the third back of the room, everyone was totally blown-away by the sound the system reproduced; The back-slap off the back wall was minimal and with the clarity and crisp 'in-the-face' experience of the ribbons at the very back of the Dome the system sounded warm and fat with clear diction. Listening to music from CD is one thing, having 92 channels of open microphones on stage with a full orchestra and rhythm section is something completely different! It truly sounded like a big HiFi system."
The Alcons equipment was a joint cooperation between The Ribbon Network members Matrix, Upstage and AV Unlimited from South-Africa.
(Lee Baldock)
