Abstract This workshop introduces electromagnetic listening as artistic research into an endangered perceptual realm: infrastructural signals that shape consumer environments while remaining largely unavailable to ordinary hearing and description. Using handheld electromagnetic detectors as audio instruments, participants take part in a single guided electromagnetic soundwalk (9 participants) that converts emissions from retail and urban systems into audible sound. The workshop treats these signal worlds as conceptually endangered because interface design and platform logics make them operationally central yet perceptually absent, and because they resist stable verbalisation. Rather than decoding signals into fixed meanings, the workshop develops a repeatable protocol for attentive listening, annotation, and comparative description. Participants work with a small set of descriptive operators (for example: pulse, drift, density, saturation, interference) to compare what is heard across different moments on the same route without forcing interpretive closure. The accompanying Research Catalogue exposition provides the protocol, a minimal route diagram, short audio excerpts, and a documentation template designed to be readable in fifteen minutes. The outcome is a systematic and transferable artistic research procedure for listening past the interface and making otherwise unhearable infrastructures discussable.