I am no engineer, but my understanding is a well made cable will reject RFI, etc., except this just means the cable will not act like an antenna and pick up noise and radio signals. If the noise is already in the signal stream, I can't see how a non-power cable can help. If a well made interconnect and speaker cable is suppose to pass the signal through the system and out to the speakers without altering or coloring the sound, then the cable should pass the noise straight through with no coloration as well. You get perfectly reproduced noise.
Logically, if I am wrong, this would mean that a recording of AC noise (as music) would come out the speakers as complete silence. Not likely.
Logically, if I am wrong, this would mean that a recording of AC noise (as music) would come out the speakers as complete silence. Not likely.