What equipment do you have near to the DSP or adjacent to the SpeakerLink wire feeding the DSP? Any devices? Small PSU's feeding switches, routers, NUC's etc?
Mostly just the G61R, the speakers, an AppleTV, and a Roon endpoint (linear PS, but yeah, still a small PS).
The whole shebang is on a Tripp Lite isolation transformer because my house is straight out of the early 1950s, and it has some of the most noisy power I can imagine considering normal, but on the audio side of the isolation transformer, things measure quite well.