Audrius Šimkūnas (aka Sala) has been working in the field of sound art for more than 15 years, his area of research is environmental sounds and their recordings. In his work, the artist is interested in quiet sounds, perhaps even inaudible without special technical means. In addition to collecting environmental sounds, local sounds, and documenting sound maps, Audrius Šimkūnas organizes sound walks, sound art workshops, and talks about acoustic ecology. A special place in his work is occupied by sounds inaudible to the ordinary ear, for which non-traditional technical means are used: underwater microphones, contact microphones, seismic sensors, electromagnetic field antennas. All this helps to reveal the inaudible world around us.