Karlheinz Stockhausen
«Spherical Concert Hall»

For the 1970 World Expo in Osaka in 1970, Germany built the world's first, and so far only, spherical concert hall. It was based on artistic concepts by Karlheinz Stockhausen and an audio-technical concept from the Electronic Studio at the Technical University in Berlin. The audience sat on a sound-permeable grid just below the centre of the sphere, 50 groups of loudspeakers arranged all around reproduced, fully in three dimensions, electro-acoustic sound compositions that had been specially commissioned or adapted for this unique space. Works by composers including Bernd Alois Zimmermann and Boris Blacher were played from the multi-track tape, along with Bach and Beethoven. In the course of the 180-day exhibition, Stockhausen and a high-calibre, 19-strong ensemble gave live concerts for over a million visitors; «Spiral,» for a soloist and short-wave receiver was played over 1300 times, for example. It was possible to achieve the three-dimensional sound distribution live, using a spherical sensor built in Berlin to feed the 50 sound sources, but a ten-channel rotary mill constructed to Stockhausen's design was deployed more frequently.

Golo Föllmer