Katedrala [The Cathedral]
computer generated environment and performance [1988, Zagreb]

Boris Bakal . theatre director, actor, media artist
Darko Fritz . visual and media artist
Stanko Juzbasic . music and media artist
Ivan Marusic Klif . visual and media artist
Goran Premec . computer programmer

Performed by Josko Lesaja

Computer coordinated multimedia environment is under controll of both performer and audience.

A   music machines / visual objects
B   video monitors which transmit events from other halls - video link / CCTV
C   slide projections  
C 1   backprojection, flashes,   (288 slides)  
C 2   backprojection, blending (20 slides)  
C 3   six computer synchronised backprojections (648 slides)  
C 4   four computer synchronised projections, at performer's body, blending (8 slides)
C 5   ten computer synchronised projections and backprojections at the scieling   (20 slides)
D   speaker systems
E   acoustically treated walls
F   new acousticallty transparent walls
G   performer's stage with brainwave (electroencephalograph) / MIDI transducer
H   photo sensor coupled to Voltage / MIDI converter
I   cameras
J   microphones
The Cathedral is an interactive work carried out through the medium of a computer which was realised in the course of six performances during the month of February, 1988 in the Gallery of Expanded Media in Zagreb and as a direct broadcast on Radio 101, Zagreb.

The place of happening is devided in three spaces. The audience arrives
into the gallery entrance-hall which the authors named after Mussorgsky. In 1874. inspired by the architectonic drawings Mussorgsky has translated visual language into a musical score in his music composition "Pictures at the Exibition". The authors have based their idea of the first space on the similar principle, where they exposed visual objects (mobiles) which are at the same time musical instruments because they produce sound. While passing through the first space the audience is followed by a camera and this image is transmitted to the monitor in the second space. At the same time the audience in the first space can follow the movement of the audience in the third space. In the second and third space there are photo sensors installed and they register the passage of the spectators and interactively trigger the sound production.

The second space is named after Vasilij Kandinsky. Here two flash-slide
projections show sketches from visual performance Kandinsky made after the above mentioned work of Mussorgsky in early 1928. Kandinsky did an inversion and brought music into visual context. It was the first documented multimedia performance, a geometrically abstracted light composition with a dramaturgical line of a happening. Apart from this reference on Kandinsky the second space also contains a kintetic-sound installation, a quotation of the "Nude Decsending a Staircase" (1912) by Marcel Duchamp, and another slide projection: an image of a clock.

The third space is named after Joseph Beuys. Therefore the audience walks
on soft floor.  An installation made of screens with Josko Lesaja (tenor) standing on top of it and singing a musical collage made of fragments from different operas occupies the central place in the room. Above the singer's head there is a pyramid shaped metal construction. We can see people passing by the two different spaces (space  one and space two) on the screens that make up installation. On the side walls there are three slide projections. During the happening, which lasts a little less than an hour, approximately a thousand images are projected. They have different origins and themes: nature phenomenas, micro and macro photography, industrial landscapes, visual material taken from the media reality and the like. This collection of images is based on formal and visual analysis of perception and contains different textures, multiplications, colour contrasts and compositional elements which allude to relationship between two-dimensional and three-dimensional, spatial illusions etc. The system of slide projections and sound is triggered and controlled in two ways (an interface with two inputs). On one hand by passing of the audience and on the other by an electroencephalograph (EEG). In a word, special sensors connected to the singer's head register activities in his brain cells and these subtle  organic moves change the production of sound and slide projections in space.  

> The Cathedral project at the Wikipedia
> more about The Cathedral project [Croatian and partly English]
> The Cathedral - The Restoration of Information [1998] project