Directional cables - what does that really mean?


Some (most) cables do sound differently depending on which end is connected to which component. It is asserted that the conductor grain orientation is determining the preferential current flow. That might well be, but in most (all) cases the audio signal is AC (electrons going back and forth in the cable), without a DC component to justify a directional flow. Wouldn't that mean that in the 1st order, a phase change should give the same effect as a cable flip?

I'm curious whether there is a different view on this that I have not considered yet.
cbozdog
Interconnects are obviously better sounding in one direction than the other. No bout a doubt it. So are fuses. Even big standard non audiophile grade fuses. No offense intended to anyone.
You guys that are using a digital coax cable with a solid core center conductor that connects your CD transport to your DAC, you should be able to hear a difference in SQ when reversing the direction of the digital cable.
Try it!
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@Jea48 - Yes, the audio signal is brought upon by the electrons doing a little alternating dance back and forth, and pushing/pulling on their neighbors to dance with them, and their neighbors pushing their next-next neighbors etc... If they would be marching together towards the end of the cable without coming back to about their original location - that uniform movement would be a DC signal that carries no audio info by itself.
09-28-15: Cbozdog

If you play a record and rely on the electrons to carry the audio signal from one end of an IC to the other end of the IC you will be waiting a hell of a long time after the record is done playing before you would hear a thing.

Quote. (Audiogon Herman)

In audio we are talking about the transfer of energy in the form of an electromagnetic wave.

Electrons and wires are not needed to transfer this energy. For example, the waves will radiate in free space or down a waveguide.

Current is the flow of charge, not electrons; however it is not needed to transfer the energy therefore the current (flow of charge) in the wire is an effect, not a cause.

At low frequencies like audio it is easier to construct a system where the energy follows a wire more easily than through space or a waveguide because the wavelength is so long and the waveguide or antenna would need to be humongous.

The water flow analogy is fatally flawed, it cannot explain everything that is happening with AC or DC. http://en.wikipedia.org/wiki/Hydraulic_analogy

Current flow is a misnomer with AC and causes great confusion since the charges are not really flowing. The periodic motion of the charge is not a flow in the conventional sense of the word. This is the only use of the word flow I have ever seen that describes periodic motion. For instance, pendulums do not flow. This basic misconception was the cause of much of the Audiogon debacle. Somebody was insisting that electrons vibrating about a fixed point could be described as current flow.

Quote:
"In audio we are talking about the transfer of energy in the form of an electromagnetic wave."

This is how an audio signal travels down a wire from the source to load, a connected receiving piece of equipment. So now the question is how can wire directionality affect the audio signal electromagnetic wave as it travels from the source to the load?
I wish I would have asked Herman that question....

Speed of electricity
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@Jea48 - when talking about electrons in motion physics calls it current and not wave. The EM wave terminology is usually reserved for radiation. However, we agree - is not "the" electron at the source that runs down the wire to pass on the information.

I'm more curious about the effect of extrusion (that sounds like pulling the wire from the melt, or further purifying it through local melting and re-crystallization to push out insoluble impurities and minimize grain boundaries). How would THAT influence directionality? (I understand that preferential shielding can impact overall noise - that would not affect signal propagation but rather the added noise from external sources).

C.
09-28-15: Jea48
You guys that are using a digital coax cable with a solid core center conductor that connects your CD transport to your DAC, you should be able to hear a difference in SQ when reversing the direction of the digital cable.
Try it!
I suspect the main reason that may occur in many systems is that the supposedly symmetrically designed digital cable is not truly symmetrical at the very high RF frequencies which comprise the risetimes and falltimes of the digital signal.

Minor physical differences between the two ends of the cable in how the connectors and wires are mated and/or soldered together will result, at the tens of megaHertz and higher frequency components which are present in those signals, in differences in VSWR-related reflection effects. Which in turn will depend on the impedance characteristics of whichever of the two components each end of the cable is connected to. Which in turn will result in differences in waveform distortion, or lack thereof, on transitions between the higher voltage and lower voltage states of the signal as received by the DAC. In turn resulting in differences in jitter on the clock the DAC will extract from that signal.

Whether or not there will be audible consequences from all of that will depend on many system-dependent variables, including the exact output impedance of the transport within whatever +/- tolerance it is designed to, the exact input impedance of the DAC within its +/- tolerance, the jitter rejection capabilities of the DAC, the characteristics of the cable (including its length and its propagation velocity, which will affect the timing of how reflections and re-reflections from both ends of the cable are seen by the DAC), the susceptibility of both components to ground loop-related noise issues, etc.

Best regards,
-- Al