BEATS (1994)
for sine wave generators, amplifiers and speakers

Two stable sine wave generators create a perfect 7:4 sept. A second pair of less stable oscillators is tuned as close as possible to these frequencies but due to the imperfection slow beatings are created which create a permanently changing rhythmical structure. One of the pitches is tuned to a room resonance.

Photo: Spiegelgrotte Museumsberg, Klangraum Flensburg, 2007

GRIGIO UNO (1996)
for sine wave generators, amplifiers and open bass speakers

By modulation of a low sine wave and acoustical closed circuit the harmonic spectrum of a bass speaker (normally not audible) can be clearly heard and "analyzed" by the resulting rhythmical structure.

Photo: Punto e basta, Stadtgalerie Kiel, 1996

GRIGIO DUE (1998)
for sine wave generators, amplifiers and horn speakers

one modulated and one unmodulated sine wave form a major second (ratio 9:8) creating overtone spectra (as in GRIGIO UNO) and ringmodulation spectra.

Photo: Galerie escale, Düsseldorf, 1999

7:6 (2001)
for metal sheets, transducers, sine wave generators and amplifiers

A minor third (ratio 7:6) created with sine waves sounds from two metal sheets and is modulated.

Photo: Stadtgalerie Kiel, 2002

SCHÜDDELN (2007)
for metal cups, transducers, sine wave generators and amplifiers

A chord with ratios 6:7:9 created with sine waves and transducers sounds from four metal cups and is modulated due to very slow beatings.

Photo: Museumsberg, Klangraum Flensburg, 2007

GRIGIO TRE (2008)
for sine wave generators, amplifiers and horn speakers

Extended,variable version of GRIGIO DUE using chords with ratios as 6:7:9.

Photo: Stadtgalerie Saarbrücken, 2009

SAMMER. HEINRICH, FREUND (1998)

Site specific, Streetlevel, Dresden, 1998