Underground AV

AUTHOR: Inavate

A large scale projection installation carried out by French experts Système Son has brought the walls of the massive “Cathedral room” to life.

Competition amongst the 100 or so natural cavern sites to attract tourists is fierce in France. Between them they attract some six million a visitors each year.

Faced with stiff challenges from other sites, the operators of Charonche Cave commissioned a 200,000 refurbishment of its out-dated sound and video system, selecting a solution based on Christie projection supplied by Système Son.

The system included two Christie Roadster S+16K projectors fitted with Twist cards. These models feature SXGA+ resolution and 16,000 lumens of brightness.

The cave’s previous, and now out of date, system had suffered at the hands of the extremes of temperature and humidity experienced below ground. Charonche Cave has 98% humidity levels and just 10 degrees Celcius of temperature all year round. This is pretty hard on the installed equipment, and Système Son therefore had to develop custom ventilated, heated and aerated enclosures for the projectors to keep them in good working order.

Underground installation proved to be a formidable challenge in itself, made more so by the uneven projection surface presented by the cave walls. Apart from surface variations, the height of the cave wall itself varies by as much as 15 metres.

The projected images are received by two side screens measuring 28 metres wide by 14 metres high, corresponding to two distinct wide spaces. Not projecting anything between them gives a sense of depth and of the cave opening up. The onboard Twist cards straightens out the image deformed by the rocky surface without any need to tweak the projectors.

44 light sources have been set up throughout the cave, including underwater to illuminate the basins. A total of 10,000 Watts of lighting have gone into that alone. 

On the audio front, Système Son selected equipment from D&B Audiotechnik set up to provide dolby 5.0 playback. 

The whole AV system is automated via DMX. When it is switched on, a DMX controller launches the three parts of the show in unison – sound, light and video.

Charonche Cave is now capable of delivering stunning visual effects to its visitors. 
“We now have a real competitive advantage and have seen our  main wish come true of thrilling those in search of fantasy and magical experiences, while reaching out to a new public that enjoys seeing images used in an original way and in different settings.”