There is the widely accepted version of directionality: In most
audio-grade shielded interconnects, as compared to standard coax,
negative has its own internal conductor and the metal shield is attached
to ground at only one end, thus defining the cable’s directionality.
Many cable manufacturers end their exploration of directionality there,
going only as far as to mark their cables for directionality based on
the relationship of shield to ground, but altogether neglecting
conductor directionality. Because we believe in directing noise to where
it can do the least harm, we, too, believe in the advantages of
controlling for the attachment of the shield. In fact, long before we
controlled for conductor directionality, AudioQuest interconnects were
also controlled for direction based on the relationship of shield to
ground.
The above quote is from Audioquest and shows how its the shield connection that is causing the directionality, despite their awareness of how the crystals initially align in their wire.
We've built amps with Audioquest wire before. At the time of installation, Audioquest made no mention whatsoever about directionality.
The idea that a wire can be directional has many of the same problems as that of a fuse being directional. In both cases one is faced with the same problem: if the wire or fuse is directional then it conducts better in one direction that another, ergo its acting like a diode.
If that is the case then we will see a DC voltage (either positive or negative depending on which way the 'diode' is connected) at the output of the wire or fuse and since no such voltage appears, we can only assume that in fact the wire or fuse is not in fact a diode.
Generally when things act like diodes that aren't supposed to, its where there is a connection and not somewhere in the middle of a conductor. Crystal radios work on this principle. Special solders (known as 'eutectic') are used to minimize diode effects in the solderjoint (and also to prevent cold solderjoints which are sort of the same thing).
I have to assume that Geoff used the quote above to make the point of the shield being the driver behind directionality in cables. If that is not the case and somehow Audioquest was trying to make a point about wire being direction and nothing else than this paragraph isn't their best marketing. But that isn't how it reads to me.
