Godfried-Willem Raes


performance by
Moniek Darge and
Godfried-Willem Raes


holosound bewitches space
red circles as demarcationlines
space vibrates by slightest movement
boundaries of magical spheres
one finger / one toe / causes waves
keys of metal sounds
waves hit the eardrum and become sounds
fascinating centre of nothingness
hearing movements
firephoenix and smoke
a spell of witchcraft / sorcery
wordless disappearing in emptiness

[Moniek Darge]


Holosound creates, translate every single movement into sound. Holosound also attemps to be a possible realisation of a dynamic multi-dimensional oscillating system, real-time controllable by means of direct and aesthetically relevant body-movement of a performer. Movement isn’t only visible, but audible as well.

A frequency modulated ultrasound-emitter is placed in a space and directed towards three ultrasound-receivers, placed on the four corners of an imaginary tetrahedron (all angles 60 degrees). The space becomes bewitched and is delimited by two red magic circles.

As soon as the performer moves in the space circumscribed by the outer sphere around the tetrahedron, each of the three receivers will detect a different differential signal within the audible range: the movement causes a Doppler-shift of the original ultrasoundwave ,and due to relatively slow body-movement, a slight pitch-shift is produced. This differential shift is within audible range.

All of the sounds are generated exclusively by the movement of the performer inside the magic circles. She plays a mysterious invisible instrument, she plays the space itself.

The second performer is sitting motionless, outside the magic spheres, operating electronics that mix and control the three signals. The resulting sum is then used as a frequency modulation source for the ultrasound-emitter. This part of the equipment constitutes a first multi-dimensional oscillating system entirely controlled in a relevant way by movement. A sound-hologram is created, and using exclusively musically relevant parameters, as opposed to systems that are basically proximity devices, mostly controlled by light.

A second three-dimensional and quadrophonic oscillating system is used in the second part of the Holosound piece. The three signals from the ultrasound-receivers are used as inputs to special magnetic transducers that force a given set of changeable objects (e.g. springs, razorblades, steeltape, plastics... at the end, even a sandwich would do the job...) to vibrate. At another spot on these objects, a pressure-transducer (we use piezoelectric discs) is attached, and the signal generated here is amplified and converted to a digital format where it can be treated in a computer-controlled modulo-N divider/multiplier. After this programmed process the signal is fed back into the vibration-transducer together with the original signal derived from the ultrasound-receivers. Thus four three-dimensional and controllable oscillating systems are created that are only triggered by the original movement.

Sinisterly the centre of the inner circle attracts the performer and irrevocably the inner witch-circle is penetrated. The audience gets to hear a scored and ever changing mix of sounds originating from the complex modes of vibration in the whole system.

Diabolic metalic sounds resonate fiercely and punish the intruder. The performer is captured by the tremendous sounds provoced by her own moves and is born again as a Phoenixbird.

[Godfried-Willem RAES]

Holosound as an audio-art installation:

At times the 'Holosound'-setup has been used as an audio-art installation project, without the logos-duo performance piece. The picture here was shot at Ars Electronica in Linz, Austria.

In august 1997 Godfried-Willem Raes made completely new equipment for this installation version such that the setup is highly simplified. All electronics are now housed in a single 19inch rack. The new transducers are mounted in top of tree RCF Monitor 8 speakers, which together with the 3 Klein and Hummel power amps make the setup complete. The new equipment has a far wider dynamic range and a better signal/noise ratio than any previous version.

Not only does the installation seduce visitors into exploring the sounds of their movements, but also it lets them explore the mysteries of ultrasonic contents of normal objects such as keys, glass, whistle tones, mica-sheets…

The new version was on display in Amsterdam from 31th of august up to 7th of september 1997 located at Zuiderspeeltuin, Barentszplein 14, Amsterdam. The show was curated by CEM (Armeno Albers). From september 15th to october 13th, the installation was up and running in the Campo Santo Chapel at Sint-Amandberg. On 23th of november it was installed at the theatre in 's Hertogenbosch, for the November Music Festival. It was mounted again on sunday 30th of november in Ghent at a popular venue called 'Vooruit' for their 'Oorsmeer' festival. In 2016 the Holosound installation was installed in the Grote Kerk (Veere, Netherlands, from april up to september).

The invisible instrument by Godfried-Willem Raes as a permanent installation in a sound-garden at the Amsterdam Ijsbreker

In October 2000, the Ijsbreker in Amsterdam purchased a Holosound installation from us for permanent installation in their sonic playground. This instrument became a special build, capable not only of producing the analog sounds intrinsic to the audio art installation, but also the midi-conversions such that the installation can be used as a freely programmable instrument / user interface for music production.

Holosound installation installed in the Guislain Museum at the occasion of the 50th annivrsary of Logos

November 9th to 11th, 2018.

The invisible instrument by Godfried-Willem Raes was acquired also by the Instrument Museum in Brussels (MIM).

This special build includes both the <Holosound> engine and the <GMT> based version of the invisible instrument, running on a Wintel platform. So both <Holosound> and <A Book of Moves>, in a specially adapted version, can be performed there. This installation was upgraded in april 2012.

Holosound interface boards are now available from the Logos labs. Please feel free to inquire for pricing, available technologies and delivery times by email.

The analog electronics for <Holosound> have undergone a major revision in 2010, using new transducer technologies and a different processing board. This new hardware setup has been used in newer pieces such as 'Differentials'created by Dominica Eyckmans in march 2010. It is also at the base of our 'Namuda Studies', using advanced wireless gesture recognition.

Last updated 2018-11-29