2001
The Unknown
interactive sound installation
(Sound In Art, Space–Galéria Priestor for Contemporary Arts, Bratislava, Slovak Republic; WackerKunst, Mühltal, Germany; Podewil, Berlin, Germany; Correnti Sonore, Centro Europeo “Luciano Ceschia”, Tarcento/UD, Italy; Electrograph03, Athens, Greece; Observatori 04, Valencia, Spain; Glück und Konsum, Wiesbaden, Germany)

As digital technology evolves, new notions of inaudibility and near-silence are to be found within the wide range of minimal electronica music. Marc Behrens is one of the explorers of this section.
His compositions as well as visual art installations are usually touching the verge of bare audibility and encourage the viewer to participate actively with heightening awareness of his/her own auditory perception process. The Unknown is Behrens’ latest electronic sound installation that consists of two sound interfaces—wall mounted discs with high frequency and low frequency speakers built into them. Sounds that come out of them can be felt as a vibration and can be intervened and explored only by viewer’s tactile interaction with discs. By this gesture the work results in an act of communication with the viewers.
Nataša Petrešin, Catalogue Sound in Art, Space–Galéria Priestor for Contemporary Art, Bratislava, Slovak Republic, 2001

Technical Description
The installation consists of two identical interface units embedded in oak wood, which work as its speaker system at the same time.
The spectator touching a brass disc which is connected with a sensor, renders audible the musical composition “behind” the installation. This composition is divided into distinguished high and low frequency tracks. The high frequency portion is listened to at very low volume via piezoceramic transducers set in the wooden plates. The low frequency parts in turn transmit to special speakers below the brass touchpad, which transform the audio frequencies into haptically perceived vibration. This creates an irritating effect upon first contact, but later transforms into a synaesthetic impression.

Thoughts
The main issue in The Unknown is the spectator’s experience. But despite the installation being silent when not touched it is not just about modulating a sound space, but rather about the limits of perception which are explored by the sensor’s function.
Very high frequencies which can be barely imagined—depending upon room noise level and hearing profile of the spectator—and very deep frequencies become a tactile, not an auditive, perception. The vibrating touchpad, on which beat patterns can occasionally be recognized within the composition, might vaguely—but never with certainty—be associated with a living being. The high frequency channel instead faintly recalls something mechanical, artificial.
Towards the end of the composition’s 15 minute cycle there appear incomprehensible, distorted radio voices and computer-cut tibetan bells which hint to unknown rites reintegrating the mechanical with the animated. This aspect connects The Unknown to the earlier installation Tokyo Circle, which concept is entirely based on ideas of ritual, creativity and magic.

After it was more or less decided to use a sound system that would render the high frequencies barely audible and the bass frequencies only perceptible as body vibration—all of which only happening with physical contact between the spectator’s hand and the sensors—a music which would not really be listened to had to be composed. It had to transform the viewer’s perception towards synaesthesy, contrasting the auditive expectations with objective visual impressions as well as physical contact and tactile feedback.
Therefore the spectator would confront an unknown—not only because the installation remained silent when untouched, but also because the sensitive channel which would be expected—the hearing sense—was not triggered. Instead of it, others were.

The unknown is a very strong, seemingly fascinating entity in mysticism—and, of course, in a literal sense, it denotes all we do not know and have not perceived. It corresponds to the idea that human curiosity grows even more when the sensitive apparatus receives less information. This notion in “audio terms” would mean that curiosity grows with scarcer sound events—integrating silence—or less audible articulations on a given background noise.