Transformers are mechanisms of different kinds, sizes, nature, appearance and - obviously - according to the specific type and model of the transformer they also emmit relatively rich range of individual sonic manifestations. Some of them belong to the category of engineering architecture (buildings of huge transformer stations for high voltage), others are inconspicuous and miniature and you can find them embedded in motherboards of your electronic devices. By definition it is "a device that transfers electric energy from one alternating-current circuit to one or more other circuits, either increasing or reducing voltage and are employed for widely varying purposes; to reduce the voltage of conventional power circuits to operate low-voltage devices, such as doorbells, or to raise the voltage from electric generators so that electric power can be transmitted over long distances." They are essential for the energy industry because they can reduce energy losses during distribution of electricity power. In the last two centuries, their development was carried out by many inventors and engineers, from John Gibbs, Etienne Goullard, through Nikola Tesla, or Pavel Jabločkov and are based on the general theory of alternating current defined by Charles Proteus Steinmetz.

In urban environment we can listen to larger transformers either as a substations in house blocks or as a electricity nods for tram, trolleybus, or railway networks. Transformer-substations located close to the living areas could induce high-long term exposures to ELMF (Extremely Low Magnetic Fields) of nearby inhabitants. In terms of functionality, the bigger external magnetic field means energy loss and therefore the construction of transformers limits it to a minimum. Their EMF (Electromagnetic Field) remains mostly inside the metal core and the copper coils and penetrates outside only occasionally. For the frequency from 4 Hz to 1 kHz, the health limit of the induced current for the area of head and chest is set at 0.01 and for others at 0.002 Ampere per square meter, i.e. five times lower. It can be assumed that the health impact of the so-called "electro-smog" caused by street transformers is rather negligible and should not have a negative impact.

Otherwise, the acoustic character of transformers allegedly has two different sources: it is a "tone noise" emitted from the core of the transformer due to so called “magnetostriction” (a property of ferromagnetic materials which causes them to expand or contract in response to a magnetic field. This effect allows magnetostrictive materials to convert electromagnetic energy into mechanical energy and we can hear it in form of vibrations of metal parts of the apparatus. Interestingly, they are hearable as multiples of the network frequency and vibrate at 100, 200, 300, 400, 500, 600 and 700 Hz as the deep hum. The volume of those sounds depends on the level of the constant voltage in the kernel and is audible constantly, day and night. Another part of acoustic behavior of transformers is the noise of fans, which are used for cooling radiators filled with oil. It is a broadband, intermittent sound and surrounds the higher voltage transformers. We can hear it mainly during the day and in summer, because during the night and in winter it is not necessary to cool.

The installation in Igloo gallery follows the piece The Radčice Transformers, which was exhibited in 2022 in Prague. This time it is a set of sound recordings from Jihlava and it presents a wide spectrum of vibrations of the Vysočina transformers (however, all belong to the dominion of ČEZ company and are interconnected to the pan-european electricity distribution system). One channel of each set complements the sonic ambient from particular location of individual transformers so one can hear as well cars, birds or wind. The listener can walk through the Igloo gallery space as if he/she would be wandering through the Jihlava streets at night (then the sounds of the electric transmission reach above the usual traffic noise level). The resulting spatial sound composition is moderated by the positions of the listener and which of six sound systems was switched on. This interactive sound composition resembles a certain branch of musical minimalism - drone music, but is also a reference to the topic of environmental pollution, a toll  we are paying for our luxury and for our carefully maintained dependence on constant supply of both fossil and "green" energy source. During the exhibition a workshop is organized where participants find out the techniques to record electromagnetic fields and frequencies, which we do not perceive by hearing, but which we still perceive in our bodies.

The theme of Jan Krtička's (1979) spatial creations is often the natural or urban landscape, the issues how to document it, the relationship between space and sound, physicality and the act of listening. In recent years, there have also been interventions into a specific space, questions of its abstraction and the concept of spatial, multi-channel sound. Inspiration from minimalism and conceptual art can be seen in his installations for gallery space (White Cube, 2006, Clean Table, 2008, John Cage: Lecture About Nothing, 2012). Similar tendencies are also manifested in his curatorial projects (Documentation, 2012 NF Gallery in Ústí nad Labem or Initial Position, 2015 Emil Filla Gallery in Ústí nad Labem). The last solo exhibition of his sound works took place in the Jilská 14 Gallery in Prague.

http://www.jankrticka.com