Belgrad state variable filter, courtesy of Xaoc
A manufacturer of modular synthesis equipment, based in Poland. 'Xaoc' is a Cyrillic transliteration of the Greek root of the English word "chaos". The company manufactures modules in the Eurorack format. The product line includes a mix of analog and digital circuitry. A notable example of the latter is the Drezno analog-digital conversion module. The module contains an 8-bit A/D converter which makes the individual bits of the converted digital value available as discrete logic signals on jacks in the panel. The performer can use Boolean logic or other signal processing functions to manipulate the bits, and then send them back to the Drezno's D/A converter, which accepts eight bits of discrete logic and converts them back into an analog signal.
Xaoc's panel designs follow a rather specific iconography. Most modules are named after cities, towns or districts in eastern Europe, and the model numbers are mostly years during the Cold War period, e.g., the Belgrad state variable filter is model 1976, and the above-mentioned Drezno is model 1989. Panels are black and silver; knobs are black and red, and some panels have a 1950s-test-equipment aesthetic. A curio is the now-discontinued Karl Marx Stadt, which was a completely built panel designed to plug onto a DIY voice module board made by Doepfer.