Powered Speaker Cables

I've never heard of powered speaker cables.

Whaaat???

You maybe messing up with networked cables such as MIT, Transperent that kind-a shunt reactance in the middle-way to the signal but at the same time increase the current loss so not every time the system will benefit from them...
Cable networks are 100%passive and I've never seen any active ones if that what you realy mean.

In my experience MIT or Transperent you should use when you need to tame hi-res brightness.

Do you mean the actively shielded cables, made by Synergistic?

Maybe Power cords for powered speakers?

I use transparent powerlink plus on my amp(bryston 4b-st) with a noticable improvement in bass extension.

I used a MIT z-cord on my pre/pro (Rotel rsp-976) with very little change, maybe a little blacker.

These are both relatively inexpensive cords, especially if bought used.

I imagine that Powercords for powered speakers would/could make an improvement.