Imagine a huge egg standing on end, a closed structure which allows a handful of people to stand in its interior and experience the sound- and lightscape it generates. This is the Klankkaatser, the Sound Rebounder, with a height of almost ten meters, equipped with a light installation and a sound machine generating sound compositions. My aim is to generate an immersive soundscape which, by subtly deranging the senses of the audience, has a hallucinating effect.

In the uppermost focus of the spheroid Klankkaatser, a small sound machine is suspended. The sound machine, which performs compositions, consists of a computer controlled musical ' ensemble ' with a blower supplying five bamboo flutes with variable wind. The loudness, pitch, and timbre of the two low drones and the three high tones can be varied by using variable wind, variable nodes, and 'speed valves'. Due to the high-pitched noise component of the flute tones, the generated sounds have an interesting richness. The concave wall of the Klankkaatser reflects the sounds of the live music toward the spheroid's second focus, which is located at ear level. Because the sound arrives at this focus from all directions rather than from just one direction, the audience will experience the music as if it were created inside their heads. Simultaneously, the light changes in colour and intensity, slowly and irregularly. As the curved wall has neither lines nor edges, there is no point for the eyes to focus on in the interior of the Klankkaatser and its visitors will visually experience an infinite space, a Ganzfeld. In these circumstances, light resembles a floating, powdery dust or smoke, and takes on an unusual material quality. The changing lightscape in the Klankkaatser is created by using hundreds of leds
capable of producing all colours. The lightscape is composed
to closely tie in with the soundscape. When that is done to perfection,
a small miracle will happen: sound and image will harmonize and
intensify one another .. (drawing Farhan Alibux)

The interior of the Klankkaatser is sober and subtle in atmosphere, yet intense. Rather than offering a sensational spectacle, it is a space for concentration and contemplation. Simplicity: a minimum of activity and the use of minimal means. Quietude: a little bit of sound and a little bit of light. Wonder instead of amazement. A space similar to a chapel or a small temple, where for a while one leaves behind one's daily life, for introspection.

Time and again, I lead my audiences into soundscapes for which I have a fascination. I spend much effort searching for suitable forms and locations for these soundscapes. In some cases I give traditional concerts for huge audiences, in other cases the soundscape is created as a site specific installation. The authenticity of sounds made on location invariably has a key role in the experience of these soundscapes. Still, I always have to deal with the specific character of the space where I present the soundscape. As these locations or venues typically have a neutral character, they are not suited for an optimal experience of my work. Invariably, adaptations to the specific acoustics of a space are necessary, as are adaptations to its architectonic character, its size, its furnishings. A work will 'behave' differently in each space. In practice, it is hardly ever possible find an ideal location for the execution of any of my works. For that reason, I am now constructing this radical space.

I am collaborating with a group of advisors and specialists in various fields to study technical aspects of the Klankkaatser, such as construction, safety, setting up and disassembling, storage and distribution, market and audience, organisation, computer technology, and of course light. The Recommending Committee consists of Job Cohen (a well known politician and the former mayor of Amsterdam), Dirk van Weelden, and Ad 's-Gravesande. The Klankkaatser will premiere in Amsterdam, at the MuziekGebouw aan 't IJ, 14 August 2010, preceding Sail and the Uitmarkt. The Klankkaatser is designed for continuous operation. As setting up and disassembling is fast and easy, the Klankkaatser can be moved to other venues and draw fresh audiences. Following the premiere, the Klankkaatser will tour through the Netherlands and abroad.

with special thanks to Muziekgebouw aan 't IJ.



Hans van Koolwijk.



Film Klankkaatser : go to 'Links'