Two copper plates hang from the ceiling of the topfloor of the immense minebuilding in Waterschei, Belgium.
One of the strings of each plate is amplified, and the amp is placed on the floor against the plate. Feedback sounds emerge, filling the whole building. Draught, people passing by, etc cause changes in the overtone structures of the sounds. The plates vibrate and deform the reflections of the roof structure of the minebuilding.
This is a musical instrument that plays and tunes itself, by measuring
pulling force and amount of vibrations. All measurement go into the electronic device, constructed by 2 students of the faculty of electric
engeneering at Technic University of Eindhoven.
The inputs can trigger all kinds of outputs, such as volume of amps,
voltage and direction of pulling motors and voltage of playing motors.
The whole system is so complex, that it becomes completely unpredictable. Besides an hommage to the city of New York, it also
puts the question: “Who is pulling the strings?”.
This work was a breaking point in our carreer. We ourselves became more fascinated by the fact that the electronic commands were 'overruled' by for instance the laws of gravity, so that a piece of swinging metal was out of reach of the motor that was supposed to hit it. That's why, from 1998 on, we started working more and more on the basis of 'letting the material do the work', and using simple and in the same time complex or unpredictable systems (like wind) as a basis
for our future work.
This is the first step in our researchproject WAVES. In the video we have replaced loudspeakers by shakers.
Shakers function like loudspeakers, but instead of producing sounds, they produce vibrations. In the piece with the paper, we had the paper hang from a long string with a piezo-pickup. The signal goes into a small mixingboard, and a line output goes from there to a hifi amp. Instead of a speaker, we used a shaker, that was mounted between the wall and the string. So we can create feedback, though not in sound, but in movement. The higher the volume, the wilder the paper moves.
In the second part we have a shaker directly mounted to a sinc plate of 1x2 meters, hanging on strings from the ceiling. One of the strings has a piezo that goes into the amp, producing feedback, that makes the plate vibrate.
The other piezo goes into a guitaramp/speaker. In the last take of the video the amplified sound of the vibrating plate can be heard.
Feedback soundinstallation by Petra Dubach and Mario van Horrik, presented 2001 in the abandonned Minebuilding in Waterschei, Belgium. Presented in the IM festival.
The copper plates hang from the ceiling on amplified strings. The speakers are placed against the plates, so they produce a low sonorous sound, that make the plates vibrate, and hitting the speakers, producing the higher sounds. Draught and people passing by influence the soundstructures. The immense building had a cellar and two floors, each measuring 100x75 meters. The sounds filled the whole building without being disturbing or overloud.