The Physics of Electricity

A few comments. The subject of the thread is speaker cables or wires, and the audio signal, not power cords. Also, why do cables with shielding often sound worse than cables without shielding if shielding is supposed to be all that? Finally, the subject is how electricity works; shielding is pretty much another topic or sub-topic.

Skin effect to the rescue! Mystery solved! The current travels inside the conductor. In the case of a fuse, if the current traveled outside the fuse wire it would not melt when required. Hel-loo, people!

Distribution of current flow in a cylindrical conductor, shown in cross section. For alternating current, the current density decreases exponentially from the surface towards the inside. The skin depth, δ, is defined as the depth where the current density is just 1/e (about 37%) of the value at the surface; it depends on the frequency of the current and the electrical and magnetic properties of the conductor.Each 3-wire bundle in this power transmission installation acts as a single conductor. A single wire using the same amount of metal per kilometer would have higher losses due to the skin effect.

Skin effect is the tendency of an alternating electric current (AC) to become distributed within a conductor such that the current density is largest near the surface of the conductor, and decreases with greater depths in the conductor. The electric current flows mainly at the "skin" of the conductor, between the outer surface and a level called the skin depth. The skin effect causes the effective resistance of the conductor to increase at higher frequencies where the skin depth is smaller, thus reducing the effective cross-section of the conductor. The skin effect is due to opposing eddy currents induced by the changing magnetic field resulting from the alternating current. At 60 Hz in copper, the skin depth is about 8.5 mm. At high frequencies the skin depth becomes much smaller. Increased AC resistance due to the skin effect can be mitigated by using specially woven litz wire. Because the interior of a large conductor carries so little of the current, tubular conductors such as pipe can be used to save weight and cost.

In the autumn of 1884, Károly Zipernowsky, Ottó Bláthy and Miksa Déri (ZBD), three engineers associated with the Ganz factory, determined that open-core devices were impractical, as they were incapable of reliably regulating voltage.[10] In their joint 1885 patent applications for novel transformers (later called ZBD transformers), they described two designs with closed magnetic circuits where copper windings were either wound around a ring core of iron wires or else surrounded by a core of iron wires.

 
Then there's the utterly unique thing about iron.

iron is the destination gateway for black holes. No matter which direction they come from (there are two directions in activity to get to a black hole)

They either move up to being iron and then black hole, or they move down to iron, and then a black hole. (just one way of phrasing it)

That hysteresis and the permeability, the unique parts of it re the table of elements.

https://en.wikipedia.org/wiki/Permeability_(electromagnetism)#Values_for_some_common_materials

Is there something beyond the normal considerations that we are simply not 'getting'? Something about... hysteresis, permeability and time-space?

Something seems to be saying that if you want to understand black holes, you have to properly and fully understand iron, and to fully understand iron, that you must consider all of what a black hole really is. 

Now..isn't that ...just..interesting.

Becoming iron actually doesn’t guarantee it will become a black hole. Far from it. Only compressed stars with mass greater than 3-4 solar masses will become black holes. The rest will become something else, a Neutron Star. Of course, no iron or any other elements exist in a black hole as they have been crunched down to their basic subatomic particles. A black hole with the mass of the Earth would fit in the palm of your hand.