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Hi,

I have a terrible radio signal coming from my rear channel speakers (that I think is called RFI). It has been basically impossible to get rid of this noise. I have a great system (NAD receiver, JM Lab speakers), so it's very, very doubtful it's the equipment. Here's my question ... my rear speaker cable runs right along side the cable for the cable T.V. Could this be the problem? Should I try to separate the cables? Any other thoughts? Do "power conditioners" help? If so, which ones? Monster? Thanks!!!

First question. How did you decide that the sound is a radio signal?
I have had many problems with NAD surround sound audio. So don't rule out equipment. (Have had good experiences with NAD stereo equipment).
Try switching your front and rear speaker wiring at the amplifier and see if the problem moves to the front (indicates that the problem lies in the electronics), or if the noise remains in the rear speakers (noise is being coupled into the speaker wires). The signal from your cable TV is very small relative to the signal in your speaker cable and not likely to cause interference. Also the frequency of your cable TV signal is way above any audible range.
I would suspect a problem with electronics.

What are you using for cables to the rear speakers?

It's your receiver picking up a radio station. Unless you have smart speakers. Smart speakers are similar to smart bombs. A laser guides a radio signal to the speaker. Do you have periods of time you cannot account for. Like one moment it is 10:00 am and the next thing you know it is after midnight and you feel as if you have been experimented on?

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Thanks, for the reply. First, why have I decided it's a radio signal? Because I can hear it in the rear channel speakers - it's a faint radio station. I'll try what you suggest, but here's why I think it's in the speaker cabling. When I move around the rear speaker cables, the sound gets either louder or softer. If it is the speaker cabling, how do I fix it? Will new speaker cable fix it? Also, the rear speaker cable runs right along side my subwoofer, which also seems to make it worse (or is this just my imagination?). Thanks!!

Your cable TV cable carries a hundred or more channels.
The fact that your rear speakers are picking up just one radio station from the tv cable and then down mixing it to audio and then applying either AM or FM decoding isn't realistic. Don't spend any money on new speaker wire to solve this problem. Get back to us after you swap the front and rear speaker cables at the receiver.

The cable is acting as an antenna.

So the interferance only shows up when you connect the wire to the sub output, and the interferance is only in the rear speakers? Either you have made a mistake in your analysis or you have a very strange system problem.

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It's your receiver picking up a radio station.