A CASSETTE OF THIS PROGRAM CAN BE ORDERED FROM THE "ORF TONBANDDIENST"
VLF or very low frequency radiation is electro-magnetic radiation that corresponds to the audio frequencies that can be heard by the human ear and the ultrasonic frequencies that are just above human hearing. This translates into magnetic fields that oscillate between 20 Hz and approximately 80,000 Hz. These frequencies of em radiation surround us constantly, but we have no direct way to sense them. They can be translated into sound through the use of a VLF receiver and speakers. Unlike the radio waves that we use for broadcast (AM, FM, cell-phones, etc.), VLF signals have a significant difference in wavelength from their lowest frequency to their highest frequency. As a result VLF receivers use some unique techniques to detect and amplify such a wide range of signals coming in from a single antenna.
In performance, I work with a magnetic field antenna and receiver. The antenna is a loop with a 3 meter circumference. It is designed so that it can be turned and swivelled in all directions. This type of antenna and movement, allows one to pull focused (directional) signals out of the environment. "Natural" VLF radiation is caused by phenomenon such as solar-flares, the aurora borealis, and lightning storms. In populated areas, this natural radiation is mixed with and often obliterated by the noise of power-lines, transformers, and fold-down from higher frequency transmitters (radio transmitters, computers, monitors, anything electronic).
By passing the output of the VLF receiver through a series of filters and frequency shifters, it is possible to remove the more annoying man-made noises (in particular power-line hum) and focus on the natural sounds mixed with more subtle frequency fold-down effects from wireless equipment and other electronic sources. In a particular performce space, the VLF fields can be mapped by the performer and turned into a composition of motion and tuning - the act of turning the antenna and moving it through space turns it into an odd musical instrument that pulls hidden sounds from the ether.