The installation consists of two aluminium parabolic reflectors
that are facing each other. The reflectors are similar that
are used as satellite antennas. The distance between the two
mirrors is preferably at least 100 meters. In this exhibition
the reflectors were placed at the open space in front of the
Each of the reflectors has a speaker in their focus point.
The speakers are playing out loud high frequency sound reflected
into a narrow beam between the dishes. The change of the frequency
is controlled by a geiger meter measuring the changes in the
local radioactive background radiation.
Inside the sound beam between the reflectors it is possible
to hear a third sound, so called modulation sound, which appears
to come from all around. The frequency of this sound is the
difference of the frequencies of the two original sounds.
Since the frequencies of the original sounds coming out of
one speakers are constantly changing also the modulation frequency
is changing accordingly.