Great advice, here. Summing up:
I will ask Audience their opinions about cords.
I will not try a slightly better cord. I will step up significantly to try something much better.
I will try both via the conditioner and straight to the wall.
I will try things one at a time, with different components, to see where the greatest differences lie.
I will not hesitate to call "no difference" if the difference is not forcefully present.
I understand better that "noise" is not always the overt, obvious kind. This is about the differences made to the background, which may already be fairly quiet but when it's made even quieter, the audible sounds will improve as a result.
Additional notes:
My wall outlets are "Porter Ports." They're supposed to be pretty good.
My Audience plugs directly into the wall. There is no place to insert a cord, there. The wiremold strip plugs into the audience and then serves everything.
So, there may already be something to improve, there.
In my new room, I hope to plug things in, thus:
Dedicated outlet #1 — monoblock amps (left and right)
Dedicated outlet #2 — source components (streamer and DAC and CD transport)
Dedicated outlets #3 — subwoofers 1, 2, 3