Video, audio and lighting equipment all played their part in the refurbishment. For visuals, the cathedral's authorities requested the use of mobile projection screens for the building.
"The problem was to provide bright, colourful pictures on very large screens perfectly visible by spectators and at the same time to organically fit the screens in the cathedral's interior without violation of its aesthetics," said Ludmila Tochanskaya, director of installation company Viking.
According to Evgeni Blinov, Viking's technical director, the solution lay in using three large-sized rear-projection screens; the middle one being 11m x 9m and two side screens with dimensions of 13m x 6m. "The central screen is fixed permanently in front of the altar part of the cathedral and can be closed by tableau curtains," he said.
"The picture is displayed on the screen by a Christie Roadster S+16K projector with 16,000 ANSI lumens, fixed permanently on the suspension of the rear (altar) wall. [The] side screens are mobile and their place is determined by the producer."
Ruton C was the company brought in to design and commission the sound system. Two configurations were required for the hall; the first with the collapsible stage in the middle of the hall, and the second with the stage beside the altar. The first version has the seats divided into three zones. "The sound in each zone is provided by loudspeakers suspended on jibs secured on the pillar walls. For side aisles, Electro-Voice XI2123/106 loudspeakers are used," said Arkadi Glukhov, technical director of Ruton C.
"As the central nave is very large, two pairs of Electro-Voice Xi 1183/64s are used for the distant zone and X12123/106s for the near zone. Six Electro-Voice X-Sub subwoofers are provided over the perimeter."
For the second configuration, seats are positioned in the centre aisle and also parts of the side aisle that connect to it. Gluklov continued: "One pair of the Electro-Voice Xi2123/106 loudspeakers located in the altar part are turned on jibs in a western direction, thus forming a portal system. The second pair of similar loudspeakers located in the side aisles is switched off.
"Loudspeakers of the central nave are switched on via the delay line. Electro-Voice X-Sub units are transferred practically into the plane of portal loudspeakers."
Separate architectural and stage lighting systems were created for the cathedral. Disart, the company in charge of architectural lighting, had to consider the building's features while also providing the opportunity for video projection.
Alexander Lapko, director of Disart, said: "Luminaires with energy-saving L-70W metal-halide lamps are used for lighting of stage curtains, with built-in LED lamps for the orientation of visitors."
Doka-Spb was responsible for configuring the stage lighting. Installation of a permanent cable network was ruled out as this would damage the cathedral's walls and floors.
The company's director general, Aleksandr Sergeev, said: "It was necessary to choose luminaries that would, first, feature high mobility and reliability, and, second, would provide maximal art opportunity for setting all performances conducted in the cathedral." Six Alpha Spot 1200 HPE effects spots were chosen. These spotlights have the functionality to create unique light pictures.