The Sound Installation ECHOS concerns itself with the characteristics and the aesthetic potential of acoustic mirror sources (the reflections), particulary with the temporal distance of their occurrence and the associated physicalness, which is produced by each acoustic event in any area, depending upon the existing architecture (the mirror). The noticed Sound is always the sum of the Original and the Reflections. With ECHOS the perceived Soundobject is not only modelled by the Original, but is produced by the shaping of this temporal Distance of the Reflections, which is to be equated the spatial Movement of the Mirror, thus the Architecture. The Mirrorsources begin to move independently from the original. Thus a secondary Doppler Effect develops; a Doppler Effect of the Mirror and not of the Original. Visual Mirrors produce likewise "sources of mirror". Since the light is much faster than the Sound, the temporal distance of the reflection is practical zero, a stretch of the now, as perceived thru the Soundobject, is missing.Among other things ECHOS examines how a visual reflection would look like if light would be as slow as sound.