In January 2009, Katy Guetta contacted us to create a design for the UNIGHTED party featuring David Guetta.<\/p>\n\n
I chose to do the Stade de France in L.Acoustics. This event has been held for three consecutive years, the last edition having taken place in Nice, with David Guetta among others. <\/p>\n\n
The configuration included a central stage, 40,000 clubbers on the parterre and part of the first bleachers, with the exception of the corners, which remained unoccupied.<\/p>\n\n
It would have been easy to imagine four towers with four stereo broadcasts, but this solution didn’t seem satisfactory for achieving a truly “big sound”. The real challenge lay in the 40-160 Hz frequency range. <\/p>\n\n
To minimize phase cancellations and lobes caused by step differences between sources, it was essential to limit their number. The idea was to group them together as much as possible to create a single source per side – otherwise the very notion of a scene would disappear. <\/p>\n\n
This grouping involved optimizing the motor points to position the bumpers so that the last V-DOSCs, located at the bottom of the line, were very close to each other, only 50 cm or 1 m apart. The result: 60 V-DOSCs, 10 SB28s and 12 dV-DOSCs per lap! <\/p>\n\n
So I reduced the system from four to two sound towers. But this posed a dilemma with regard to stereo, as it would have to be largely sacrificed for a majority of listeners. In the end, I came up with a loss-limiting solution: the four source lines on each side alternated left and right channels, a L-R-L-R arrangement. <\/p>\n\n
Once the layout had been defined, all that remained was to organize the subs. I was determined to position some of them high up, but the first problem came from the bumpers, which could only support eight caissons – not enough. To get around this limitation, I used two bumpers per side, placed one under the other thanks to a clever trick: the first bumper was hung at a single central point, while the second was suspended below at two points, its motor chains passing on either side of the first six subs. <\/p>\n\n
In all, there were 13 Motors hanging 15 m high<\/strong> from a metal frame built for the occasion, and for which I had calculated and drawn the position of each motor point.<\/p>\n\n 13 motors: 3 for the Sub, 2 for the 2 inner systems and 3 for the 2 outer systems, as I had used Delta to adjust the angles.<\/p>\n\n That left the subwoofers on the floor … the problem here was the risk that, by arranging the subwoofers around the Round Stage, the DJ would be overwhelmed by the low frequencies … don’t forget that there were also 24 x SB28 …. in the air, hence the idea of making 6 packs of 8 subwoofers in cardio mode<\/strong> to ensure good rejection in the center and therefore at the turntables. The first year, there was a dance floor at the top of the first bleachers at each end of the stadium, so I added 6 Dvdosc and 2 subwoofers per side to clarify this area.<\/p>\n\n We arrived at 6 a.m.<\/strong> and after a slight delay due to the absence of hooks at the end of the engine chains….. a detail ….? by 9am, work had begun in earnest and by 4pm everything was in the air. Time enough to test all the boxes ….. 120 Vdosc 44 DVdosc … 74 sub … we began a series of measurements, but I was already reassured: all the boxes were there, all the amp racks (around 20 per side) all the wiring (we needed the right lengths to put the amps under the stage). After a quick test, I knew my design would work.<\/p>\n\n It worked so well that I reproduced it identically the following 2 years <\/strong>(I just slightly reduced the amount of V for Nice).<\/p>\n\n Here’s a time lapse of the 1st montage:<\/p>\n\nSubwofer management<\/h2>\n\n
Cardio mode with the SB218s meant 2 x 4 subwoofers separated by 50cm. So we used the sub carts that Potar had to prepare 6x (2x4SB218) separated by 2 cleats of 50 cm, and therefore perfectly mobile, which proved to be a great help in allowing the other teams around the stage to work undisturbed. Once the space was clear, it was a simple matter of moving the 6 packs back into place and wiring them up. <\/p>\n\nCourse of the assembly day<\/h2>\n\n
Conclusion<\/h2>\n\n