By the summer of 2009 it had become clear to the Congress Centre operators that a new solution was urgently needed. The original lighting system, dating from the 1970s, consisted of 14 5kW Fresnel luminaires, suspended from telescopic poles left and right of the orchestra podium. 30 1kW tungsten halogen floodlights were rigged 10 meters above the stage to fill in shadows.
In total, over 100kW of power was used to light an orchestral performance or rehearsal, plus the power drawn by the air-conditioning (HVAC) system. The tungsten halogen light sources raised the stage temperature to around 20°, which then had to be rapidly reduced by the HVAC.
A further problem was that the telescopic suspension systems were at the end of their operating lifetime and required replacing.
The city of Strasbourg decided to seek a modern lighting solution for their prestigious venue. During consultations, ADB's newly developed ALC4 LED modular luminaire was proposed, with a new reflector, designed by ADB's R&D department, that narrowed the beam angle to 36°. This luminaire delivers high energy efficiency, employing four advanced RGB+White LED light sources to deliver the equivalent of 1250W of halogen power for an actual power consumption of just 200W.
With a choice of interchangeable reflectors and barndoors, it's capable of use as a cyclorama light, side light, footlight or for any set design requiring evenly spread areas of light. In this case it was specified to be used as a downlight, replacing floodlights.
On-site tests convinced the client and consultants that the second-generation ALC4-2's 8000-lumen power easily met the specification to light the world class Strasbourg orchestra uniformly with 1000 lux.
The final design included 54 ALC4-2 luminaires with the new 36° reflectors. A further touch was to position three ADB WARP/Motorised luminaires above the orchestra to highlight the conductor, making his gestures easier to see for the musicians, as well as accentuating the conductor for the audience, along with other moving lights in the positions previously occupied by the 5kW Fresnel units. Together with the ALC4-2 luminaires in colour mixing mode, these fixtures are used for other events requiring colourful lighting solutions.
The change of lighting concept from side lighting to central down-lighting using ALC4-2 LED luminaires with 36° reflectors mean that less flare is produced and musicians feel less blinded by bright light sources. The single luminaires are also evenly spread out across the width of the stage to create homogenous lighting.
Denis Fenninger, head of the project for Lagona SAS, based in Schiltigheim, France, says that while the ALC4-2's flicker-free light output is ideal for broadcast applications, early rehearsals with the orchestra saw an unexpected benefit from the tuneable colour temperature mode. "Some of the musical scores are already many years old," he comments, "and the paper is a bit yellow and faded. The musicians found that this music became much easier to read when we raised the colour temperature from 3200K to higher Kelvin values - the light becoming slightly more blueish, resulting in higher contrast."
The final step was the release of ALC4-2 IES files, which allowed the installation team to check the measurable results with the DIALux lighting simulation program. The ALC4-2 IES files for all optical reflector systems have been made publically available via the ADB website, where they can be downloaded free of charge.
ADB sales manager Alain Vincent says,"There was great teamwork between our R&D, our distribution partner Lagona and the consultant who trusted our cap
