New basement theater area with Klipsch 12 synergy series. Humming... Please help

[Adam12345]

I have newly finished basement space with a Dolby Atmos set up. I'm running a Klipsch 12hg synergy series 300 watt sub. I have a box built in the back of the room for the sub and I'm running a 55 foot Rca cord back there. I get constant hum when the RCA cord is plugged. When the RCA cord is not plugged in and the sub is on, I do not get this hum. I still get the hum when the Rca is plugged into the sub and Unplugged from the receiver. I've been ripping my hair out in frustration. Please help. Much appreciated

 

[WaynePflughaupt]

Make sure the RCA cable is shielded. If it looks like two small wires side by side, similar to lamp cord, the cable is not shielded, and that’s probably the source of the noise. If the cable is indeed shielded, it’s possible that it’s bad (internally has an either an open or shorted conductor).

If that’s not the case, the sub is probably plugged into a different circuit than the rest of the equipment. That’s going to be tough to fix.

Regards,
Wayne A. Pflughaupt