*Zeitraum* (German for “timespan”, literally “time space”) is a sound environment exposing the interrelation of time and space in acoustic communication. The environment is composed of many identical sound sources dispersed irregularly in a large space, playing an aleatoric ostinato of percussive sounds. When listened to from a particular location (the sweet spot), the pattern is perceived as an accented but isochronous pulse. The ostinato is structured so that the sounds from all sources arrive at the sweet spot with the same delay, compensating for the differences in propagation time. As one moves away from the sweet spot, the regular pulse becomes increasingly distorted as the distances to all sound sources change and with them the propagation delays from the sources to the listener. What starts as almost imperceptible deviations and passes through various areas with different kinds of grooves, ends up in a rhythmically completely disrupted and apparently chaotic sequence of events when listened to far from the sweet spot. By moving about the space, the audience explores a space literally made out of time, a time space—a bewildering experience enacted through one’s movement, revealing the always baffling relativity of observation.

Although the time lag between lightning and thunder is a well-known phenomenon—being evidence of sound’s relatively slow propagation speed of about 1.200 km/h, which is about 870,000 times slower than the speed of light—it is surprising to experience that this fundamental condition of acoustic communication can completely disrupt the rhythmical integrity of a regular but spatialized musical structure. *Zeitraum* reveals what skilled musicians unconsciously compensate for when playing together over bigger distances: the fact that sound takes a considerable amount of time to reach our ears—considerable with respect to rhythmical structures in music and already occurring in smaller concert halls. It also reveals the ear as a high-precision measuring instrument for time intervals. Once synced on a pulse, it can distinguish very small deviations from an expected next beat. Such deviations may be experienced as a pleasant groove or an irritating irregularity depending on the context and listening habits. Most of these aspects may remain unconscious to the listener, which will not lessen the pleasure of exploring how the time-space keeps transforming the ostinato. Thus the environment offers both a rich aesthetic experience and much to reflect upon for those inclined to do so.

The latter is particularly supported by the sound design, which permits verbal communication among the audience. Neither does speaking interfere with the work nor do the percussive sounds impede spontaneous conversations among the listeners while collectively exploring the work. Hence, besides establishing a time-space, *Zeitraum* also creates a social space, enabling the audience to deepen their experience and understanding through communication.

Links: http://www.researchcatalogue.net/view/94547/141743

Gerhard Eckel (AT) is an artist using sound to explore ways of world making. He aims to articulate the aesthetic and epistemic dimensions of art, understanding artistic experience as a compound of action, perception and reflection. His works are the results of research processes drawing on the practice and theory of music composition, sound art, choreography and dance, installation art, interaction design and digital instrument making. Gerhard Eckel is a professor of computer music and multimedia at the University of Music and Performing Arts Graz in Austria. He also serves as affiliate professor at the KTH Royal Institute of Technology and as visiting professor at the Royal College of Music in Stockholm.