During the mid twentieth century, space was developed as a composable dimension. Composers used the three spatial dimensions in their own fashion, but space was understood primarily as an abstract concept. It was not until the development of sound installation art that space was discovered in a concrete manner, explored, performed in and could even acquire its own specificity, called site-sound (Ortsklang).

The article shows consequences and strategies of site-sound installations in three sections – from spatial sound to site-sound, public space as performance venue, and public strategies (acoustic interventions, interactive installations and participatory projects) – with three examples of site-sound installations (Site-Sound Marl Mitte, meta.stases and towersounds.2: watch tower).

Acoustic art in public spaces basically involves installing a space in another existing space, both physically and sensorially, and metaphysically and mentally – an interior space in an exterior space, so to speak. The original quality of sound art lies in the oscillation of interior and exterior space. Thus public spaces intensified by sound art cause transitional spaces to come into being, in a political and a psychoanalytic sense.