Does anyone know he possible cause of loud static noise in a Simplex 4010 speaker system? We have replaced the audio control board but there was no change. It is so loud that you cannot hear the recorded voice message that plays to evacuate the building.
Maybe it’s SLC chatter? This could happen if the SLC uses non-shielded wiring and is in the same conduit as the speaker wire. (I have never heard of it to this extreme, though!)