Power cable makes a difference?
The current is sourced from a transformer placed somewhere far away outside the building. Then it passes several long cables to the building main panel where is distributed through other cables to each apartment or whatever place. Then it goes in the home distribution panel and then to each plug.
If someone is saying that the last 2 meters of cable can change the sound of a subwoofer while the current is passing through hundreds or thousands of meters of cables and hundreds of connectors + a few panels ... maybe they can explain us how !
I can understand that the RCA / XLR / or other cables placed between a sound source and final speaker can make a difference (if really bad cables are replaced with decent / cables) but the power cable can do absolutely nothing unless it is damaged or too thin.