AC captive cords???

How about changing the sub over to an IEC type connector.
The 1st time I changed some captive cords with better quality power wire, I wasn't elated with the result.
Made cord comparisions length changes easier too.

parts express IEC's

Carefully wrap the cord with twenty dollar bills. Be sure to use cryo-treated scotch tape to hold them in place. For even better results, try fifty dollar bills.

Eldartford,

It's important to note that the bills must be the older, 'uncolored' versions. The dyes in the newer bills increase dielectric absorption, and will result in significant coloration in the upper to upper-upper googlehertz region. Of course it can be difficult to hear the difference if your system isn't tweaked properly. I find isolating my loudspeakers from the floor with short stacks of 100 dollar bills really increases the dynamic slam and midrange bloom, especially when listening to vinyl that has been properly 'burned in' by repeated playing for a minimum of 25 years.
As always, YMMV.

(Thanks for letting me play, I needed a good chuckle today)