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.
The electrons go back and forth, at least somewhat and at very low speed, they are virtually standing still, but the signal does not go back and forth. That's the issue. Thus any wire or cable will sound better in one direction than the other. This includes wire inside speakers, wire inside transformers, internal wiring of components, fuses, etc.
If audio cables are too long, you don't get lost looking for source or receiver by following arrows:


Please note to follow arrows when dealing with long wires so you don't get lost between SOURCE and RECEIVER.
"without a DC component to justify a directional flow"

I can't answer all of your questions, but I think Audioquest has dealt with that issue using their DBS system.
As far as I know it has to do with shielding to minimize interference from other sources and line voltage noise. The shield is only connected at one end to minimize ground loops from one item to the other also.
but the signal does not go back and forth
Interesting concept. Please define "signal."
Some cables have a gadget, like MIT network boxes, at one end versus another. That would at least seem to have some concrete basis for saying the two ends are functionally different and hence might produce different results one way versus the other.

Beyond that, if the darn thing has arrows on it, I point them downstream as instructed ie pointing from the source to pre-amp or pre-amp to amp. Just because there are arrows on the darn things, but for no concrete reason I could identify.

I've dabbled with a lot of wires over the years and am finicky about sound quality. But that's about the extent to which I worry about such things. Shame on me.
Some said, "define the signal." I define what it's not, how's that? It's not the electrons. AC is what, alternating current? Guess what? It's not the current either.

Geoff - hmm. The information flows in one direction (from source to receiver, as Czarivey kindly sketched out for us), with an alternating flow of electrons (back and forth, or forth and back depending on the phase) as carrier. No carrier, no information - unless I'm sadly mistaken about how things work in this universe.

Mapman and Hevac1 - thank you - preferential grounding and the magical network gadget look like legitimate reasons. Short of that - I am inclined to view with suspicion any cable that is overtly directional. I would also expect such cable be also more sensitive to phase inversion (though I did not check experimentally).

Thank you for chipping in - I learned.

"09-25-15: Hevac1
As far as I know it has to do with shielding to minimize interference from other sources and line voltage noise. The shield is only connected at one end to minimize ground loops from one item to the other also."

Its done to form/polarize the dielectric one way. Thats why they use the arrows. If you go to AQ's website, they do a much better job explaining it than I do.
Bozdog, but we're not talking about the carrier, we're talking about the signal. The signal travels at near light speed. The elections on the other hand travel about a foot an hour. Hel-loo! The signal in the room is the acoustic wave, not the air, no?
"The signal in the room is the acoustic wave, not the air, no?"

Don't you need both? You can't have an acoustic wave with out air. Or am I just missing something?

Also, with regards to the signal alternating back and forth, doesn't that get taken care of when the signal is rectified?
Actually, AC & DC electrical charge/flow is directional (from sender/source) but with AC the electrons move back and forth (which is AC electrical current) :)
Umm... no, I'd be surprised to find that we purposefully rectify audio signals. That would, as you indicate, keep electrons moving in one direction only, while folding one phase over the other with a couple of diodes (or cutting out one phase altogether with a single one?). Probably not happening that way, unless it is a mild, unintended effect of the interconnect (directional?).

Thank you for correcting Geoff's view.
I never said you don't need both. What do you think that proves? You need electrons, too, but they can't be the signal, they don't travel fast enough. They are virtually moving whereas the signal is traveling at near light speed. Air molecules in the room are at rest, the acoustic wave is traveling through them at the speed of sound. So air can't be the signal any more than electrons. They are the medium not the message.
The rectifier converts alternating current to direct current. That's true. But the current is not the signal. Besides the last time I looked the (directional) fuse in amps is inserted in FRONT of the rectifier. Hel-loo!
Nothing substantial for speaker cables... Ac current comes out your amp.
It's a concept born in the marketing dept as a mean to differentiate the product.
For interconnects, idk.
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Jea48 - yes... seems that the question is not new. I should have looked at prior art before starting a new tread. Bummer.
"Thank you for correcting Geoff's view.
Cbozdog (Reviews | Threads | Answers | This Thread)"

I wasn't trying to correct anyone. I wasn't sure myself and was just looking to see if I had it right or not.
For interconnects with a shield there is less EMF/RFI pickup, when the shield is connected only at the source end.

EMI/RFI may or my not be a problem. It depends on if radio waves or power cables are nearby.
Geoffkait said: "The electrons go back and forth, at least somewhat and at very low speed, they are virtually standing still..."

So are we to assume you have proven Dr. Heisenberg's Uncertainty Principle to be invalid?
We can measure the precise speed of the electrons. That much is certain.
The different cable theories I have encountered have mostly been covered above, but I think the following should complete the story.

1. Cables with shield connected at one end.
This is referred to as a floating shield design. The purpose of this design is to conduct any induced RFI/EMI away to a single grounded point.

Ideally, the end with the shield attached should be connected to the source of the signal - regardless of where that component is in the audio "chain" - e.g. for a Pre-amp to amp connection the end with the shield attached should be connected to the pre-amp.

This prevents any RFI/EMI noise from being communicated to the next piece of "amplification" in the audio chain - resulting in a quieter signal.

The problem with using these cables is - it relies on all of your components being correctly grounded.

However, components that use a two pin plug or a Wal-Wart power supply can experience grounding issues (i.e. because they are isolated) so for them, connecting the cables in the other direction may actually be more beneficial.

One such component I have actually had a measurable potential on the neutral side of the RCA output.

One way around this imperfect setup may be to ground the chassis/case of components using this kind of power supply design. This does not guarantee success - as it really depends on the component's design, but it's worked for my components

2. Conductor Extrusion effects.
When the wire is being extruded is has an effect on the crystalline structure of the material being used, which in turn MAY effect signal transmission in some way.

Whether you believe it or not, there are many cases reported on this forum of cables sounding different and there are several well documented reasoning's for this on the web, but one thing for certain, many cable manufacturers put little arrows on their cables in order for the user to get them both connected in the same direction.

One thing for sure - IF - there is some sort of rectification effect, you would want it to be applied in the same manner to both left and right channels, otherwise it would effect the phase of the signals between the two channels and degrade the sound.

So - it is advisable to connect both cables in the same direction - hence the little arrows, but which direction may well be system dependent

3. Cable architectures
There are some very complex cable architectures out there now and connecting such cables one way or the other may have any effect on sound.

However - you DO want to have both cables connected in the same direction - hence the little arrows.

A cable architecture can be responsible for a noticeable degradation or improvement of sound - depending on which way round they are connected and in general the manufacturer gets the little arrows right, but there is no harm in trying them the other way around - just to see :-)

So, to sum up - in some cases the little arrows may only be there to ensure you get both cables connected in the same direction because the manufacturer believes it to be important. The actual direction BOTH cables must be connected in may be system dependent.

If a cable uses the floating shield design then it should be stated somewhere in the manufacturers literature, together with the "direction" the arrows should be connected.

One company I know uses this method is Van den Hul and they document it quite well.

Of course, there are those that believe a company will add little arrows on their higher end products just as a selling feature - just sayin :-)

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1. Cables with shield connected at one end.
2. Conductor Extrusion effects.
3. Cable architectures
No. 1 can affect noise, could be sonically discernable, and so should be followed,
No. 2 can be discerned visually by microscopy but I have never heard of this being reliably identified in a listening test and IMO falls into the same category as directional fuses, jackalopes, and other urban myths, so...if you want to believe then believe, and
No. 3 is pretty simple...if there are arrows on your cables, point them in the downstream direction, e.g., from the source toward the speakers.
for the believers...
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.
@WillieWonka - Thank you for the summary, makes sense for practical use. I continue being suspicious about the arrows, but I understand and agree with your explanation: some of the reasons are legit. Thanks.

@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.
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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).

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
Cbozdog - Mitch2 indicated above that the effect of grain boundaries phenomenon is perhaps "minimal"

But something that has far more impact on SQ than grain boundaries is the cable architecture itself.

Here's a summary of what I have tried and observed over the last couple of years.

I started with Van den Hul d102 MK III using the floating shield design - that proved to be quieter and more detailed than the other cables I had been using.

The problem with more "conventional designs" that utilize two conductors in parallel is that they suffer "noise" that is induced from the signal conductor into the neutral conductor. This flows back into the connected components and impacts their performance. Sure, manufacturers put a slight twist in the conductors which is supposed to minimize induce noise, but it is not really enough.

I then moved to Stager Silver Solids - which has a very tight twisted pair (no shield) architecture - which were much more detailed and the tight twisting combats RFI/EMI and induction from the signal to the neutral, resulting in a blacker background and quieter operation.

Then I tried a braided architecture, where the two conductors were braided with thick single strand nylon. This separated the two conductors and increased the angle at which they crossed, reducing RFI/EMI and induced noise. These were significantly better than the Stagers across the board and I actually used the conductors from the stagers to construct them - so the materials used were identical.

I then started playing with my own Spiral designs where the neutral is wound around the signal conductor
- Winding the neutral around the signal effectively places the neutral conductor at close to right angles to the signal conductor which minimizes induced noise.

I have since tried several variants of this design, with the latest working extremely well.
- Basically, the signal is a single strand of solid silver wire
- The neutral is four twisted pairs of CAT6 wound around the signal.
- One wire of each twisted pair is cut short and remains unconnected at one end and basically acts like a floating shield and interferes with induced EMI/RFI.

The signal and neutral conductors are different lengths and different materials - but it does not matter, because when you take a look at the roles each conductor actually performs from the perspective of an actual circuit diagram you will see that the signal conductor is the only one that carries the "music" - the neutral conductor actually only maintains a connection between the neutral sides (i.e. ZERO volts) of the connected components. OK - it does also completes the circuit, but it is very important that the neutral side is kept as close as possible to zero volts for each component to perform to it's optimum.

Friends have also tried the spiral design and reported significant improvements in SQ.

Take a look at these links for a more complete explanation...

A couple of companies that I know offer cables designed along similar lines are:
- Anticables (for IC's)
- KLE Innovations (for IC's and speaker cables)

I have also applied the same spiral design to power cables and the effect was outstanding with a vast improvement in dynamic performance, clarity, image size and performer placement.

I personally agree with Mitch2, so I have stopped concerning myself with crystal boundaries issues - I can't do anything about them anyway - except keep both cables connected in the same direction :-)

For me - selecting the right cable architecture has provided huge improvements in SQ and has elevated my systems performance way beyond its modest price point.

Al wrote in response to the post by Jea48,

""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."

Unfortunately for that argument, interesting as it may be, is that many cable manufacturers mark their digital cables with arrows that are accorded the cables based on how the metal conductors come off the final die. All one need do is keep track of the conductor's orientation from the time it comes off the die until it's incorporated into the cable. So, it is the directionality of the cable that is responsible for the change in sound - just as shown by the Hi Fi Tuning data regarding directionality of fuses, I.e. Voltage drop across the wire is different depending on direction, for example.
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Jim (Jea48), yes I agree. My basic point is that in the case of digital cables, at least, one does not have to necessarily believe in the directionality of wire itself in order to recognize that the direction in which a symmetrically designed cable is connected can make a perceptible difference.

Best regards,
-- Al
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Had to choose one of many threads on the topic. Dart hit this one...

On Directionality:

by Roger Skoff // Positive Feedback "Which Way to Run a Cable"

David, you beat me to it. I just read Roger’s article and was going to link it here. FYI, for those interested, read Roger’s other articles on cables at the same site and let it all sink in.

All the best,

Had to choose one of many threads on the topic. Dart hit this one...

On Directionality:

by Roger Skoff // Positive Feedback "Which Way to Run a Cable"

Thanks for the link.  Will read later with a glass of wine :-)
While I don’t really have an explanation, it hardly seems possible to me that minuscule traces of impurities that might be found in 6 nines copper can be responsible for the rather impressive changes to the sound when reversing cables. This was also the point made by HiFi Tuning in their results of a thorough evaluation of audiophile fuses, which appears on the Data Sheets on the HiFi Tuning website.

What HiFi Tuning says, in effect, is the relatively small measured differences in voltage drop for the fuses under evaluation, don’t completely explain the relatively large differences experienced in listening tests. [In fact, the measured differences were much smaller than HiFi Tuning states (5%) on the Data Sheets, by almost AN ORDER OF MAGNITUDE. Hel-loo!] So, I hereby declare considerable mystery still surrounds the whole directionality thing. Fortunately, all the world loves a mystery, right? 😛
And another thing. Roger Skoff’s theory that for continuous cast copper or long grain copper wire that impurities that build up between grains causes wire directionality doesn’t make sense since any effects of impurity build-up would be random in nature, whereas wire directionality is not random. It’s predictable, transferrable and repeatable. If it was random you couldn’t control it. I scoff at his theory. 🤔 If it doesn’t make sense it’s not true. - Judge Judy

Addendum - He also left out the most important part of the whole directionality theory - how the audio or electrical signal is affected/changed by reversing the direction of the wire or cable. I.e., why is the sound better one way that the other? If the sound is more distorted in one direction, why?
Did you read the article, or just skim it? 

He said that impurities can be a reason for the difference in sound in wire directionality. The impurities can act like diodes, allowing the signal an easier path one way over the other. They can also act like tiny magnets.

He also says that when the metal is drawn and compresses the metal to the desired gauge, it aligns the crystal structure in a certain direction, favoring one way over the other. 

So, he did address it.

All the best,
All of that makes no sense. The percentage of impurities is too small. If the copper is 6 nines pure, then the total impurities is only 0.000001. Tiny magnets, indeed. Give me a break! Plus even if the impurities did act like tiny diodes there’s nothing to support the idea they would all be pointed in the same direction. There would be more than just one.
He never said that all of the impurities would align the cable direction in one way over the other, but that it would/could create a conflict, of sorts (my words).

I’ve been told by a few cable makers that there’s no such thing as 6 nines pure anything when it comes to cables, so....

That, and when an argument is made that a tiny wire in a fuse can make a difference, who’s to say that small amounts of impurities that occur in crystal structure boundaries can’t have an effect? He never said it did, but that it could, which is why he's a fan of large crystal structures that one can achieve in an easier way with single, solid core wires as it eliminates, or minimizes, the possibilities. 

All the best,
Here's the one thing Skoff said that really matters:
 there's no way—other than by listening to it—to determine which direction a piece of wire's "preferred" direction of signal flow may be.

Actually for cables manufactured by Audioquest, Anti Cables, Goertz and perhaps others you can rely on the arrows 🔜 provided on the cables since those companies control directionality for those cables. In those cases you do not have to listen to the cables both ways. Obviously, for everything else you have to listen to the cables both ways. But seriously, who really does? Not too many!  It’s also why you can rely on the fact the Audioquest high end power cords will be in the correct direction when you plug them in. Because they are controlled for directionality. Ditto the AQ HDMI cables.