... abit confused: how does a power cord affect the presentation of sound...

Can we think about this logically (can we?)?

So long as the metallurgical properties of the cable are capable of carrying the AC, and so long as the size of the wire is sufficient to the current draw, then it seems to me that the ways in which a PC can affect the component being powered by it (and possibly components downstream) are two:

* the cable is acting as some kind of filter on the AC it's getting from the receptacle

* the cable is acting as some kind of shield that is rejecting some kind of outside electrical interference

What other possibilities are there?

I repeat: if a PC is supplying enough juice to a component (sufficient awg and OK metallurgy), then if you hear a difference it must be because of one or both of two reasons: the PC is doing something to the current flowing through it, and/or the PC is protecting the current from some sort of contamination from outside.  What other options are there?

For instance, Wireworld says their PCs block (outside) interference and absorb (inside) tribolectric noise.

What is most disheartening is the usual level of debate in these threads.

Most often it goes something like this:

Yes they do.

No they don't.

Yes they do.

No they don't.

Yes they do...

Many cable manufacturers don't help, with the promotional verbiage that makes any electrical or electronic engineer roll their eyes.

I quoted Wireworld's claims above.  Can anybody comment on them with some reasonable degree of level-headed knowledge/insight?

When we can't make any further progress with the debate, let's instead debate how we debate.

I suppose that's why Aristotle dabbled in meta-physics.