I've heard people say that coils of xlr or dmx can create a problematic electromagnetic coil, despite having such a weak electrical signal. But in every gig theres always a coil somewhere,
Stage Ninja Stage Ninja XLR-48-S 42 ft. Retractable Female XLR Cable Reel - Black XLR-48-S | Zoro
Sommer cable Shop | Aes / ebu / dmx512 Binary 434 DMX512, 4 x 0.34 mm² | XLR / XLR, NEUTRIK® on cable spool | purchase online