What is Modular synthesis?
Modular synthesis is sound creation using separate hardware or software modules — oscillators, filters, envelopes, sequencers — connected freely with patch cables, so the signal flow itself becomes a creative decision rather than a fixed architecture.
In techno, modular (especially the Eurorack format) is prized for generative sequencing, organic modulation and textures that fixed-architecture synths don't produce — many artists build entire live sets around a single patched system. The learning curve is real and the hobby is expensive, but the concepts (signal flow, control voltage, modulation routing) transfer directly to software: VCV Rack is free and Ableton's tools cover much of the ground. Learn the concepts first; buy cables later.