An excerpt for the OP article,
“While wire directionality is not fully understood, it is clear that because of the wire casting process, the internal grain structure of the conductor has a slight chevron shape, and it is this physical difference that is consistent with which direction the wire sounds better. When the directionality is “backwards” there is a loss of resolution, cymbals sound like a spray-can and are truncated, voices are grainy and lack presences, the sound stage is flattened, and bass is less defined. When the wire directionality is correct, the music is more relaxed, resolving, delineated, more present, open, and believable.”
>>>>While that doesn’t really explain the mechanism, the operational details, for what is happening to the signal, it does a good job explaining what the sonic effects of directionality are.