Wednesday, October 23, 2019

Directionality of cables?

février 6, 2010 by · Leave a Comment 


The Signal Collection

[NOTE: Recently I wrote a little blog entry over on Stereomatic, addressing the notion of directionality in cables, based on my limited knowledge and my desire to run my mouth off like a good Italian boy. I’ve re-written it here, with some further clarifying ideas added. I hope you enjoy it, and would love to hear any feedback you might have. I’ll post this also as a blog entry to the site.]

So … I’ve been asked the question about the « directionality » of my cables ever since I’ve been designing and manufacturing cable for the audio industry. There persists this notion that somehow signal cables (interconnects, speaker cables, digital cables) are « directional. »

For those of you who don’t understand this bit of Hi Fi vernacular, I’ll explain it like this: Your speaker cable has two ends to it – the end that will get connected to your amplifier, and the end that will get connected to your speaker.

Imagine that you have them hooked up, and then you mark the amplifier-end of the cable with an « A » and the loudspeaker end of the cable with a « B » – so that you have identified an orientation of that cable. Now, reverse the ends so that the « A » end is connected to the loudspeaker, and vice versa.

One can hear a slight difference or change in the quality of sound when this reversal is performed, and some people claim that this difference, prima fascie, is sufficient evidence to prove that the speaker cable itself must be more efficient (or somehow otherwise « better ») when oriented in one direction vs. the other.

Some industry folks have even theorized that the crystals in the metal wire’s lattice are somehow diodic (a diode is like a one-way valve, permitting signal to travel in one direction but not in the other), and the orientation of these crystals within the wire will determine the appropriate « direction » to orient your speaker cable.

Therefore: I would like to address the notion of directionality in a signal cable as regards a better or worse orientation for a cable.

I believe that this notion doesn’t comport with the generally accepted working model of alternating current. That is to say: I think « directionality, » as it is used to infer some manner of diodicity in cable, is tantamount to « magical thinking » – attributing an observation to an impossible cause.

My Argument :

The signals traveling through a cable are alternating current (AC) which simply means that the « direction » of the signal changes for every half of every cycle of every frequency.

An AC signal is not analogous to water being pushed down a hose, from one end to the other. Rather, an AC signal travels in one direction toward the speaker for the positive-phase of the waveform, and then travels toward the amplifier for the negative-phase of the waveform.

Half the time it’s headed to the speaker, half the time it’s headed to the amplifier.
Back and forth, like a piston … and if you have ever seen a woofer move back and forth like a piston you not only have a visual and mechanical analogy of what is happening electrically within the cable, you have the direct effect and evidence of it.

So … if the signal is working back and forth between amplifier and speaker much the way a piston moves up and down or a woofer moves in and out, what does this mean to the issue of directionality?

It simply means that if a cable is « directional » at all, and that directionality could somehow mess up the signal, no matter how you orient that cable – 1/2 of your signal will always be messed up: either the negative half of the waveform or the positive half of the waveform.
So if you’re reorienting your cable for directionality, you’d simply be choosing which half to deform without ever knowing which half you’ve chosen (because we cannot inspect and confirm the directionality or « diodicity » of metal crystals in a cable).

What all this means is that your speaker cables, interconnects, digital cables … are either not actually « directional, » or if they were, you wouldn’t be able to tell because no matter how you oriented the cable, they would always be affecting/deforming one half of every waveform within the overall signal.
So the notion of directionality in audio cables is untestable, unfalsifiable, and therefore meaningless to the responsible observer.

« But! » you say … « I have heard it with my own ears! » – I have too (or at least I’ve heard something). I have reoriented wires and heard small differences. After a long while, I have also re-reoriented them and heard differences once again. Better? Worse? Hard to say. At least different.
There are any number of possibilities at work here, but I doubt sincerely that any of them are of a « directional » or « diodic » nature, given the behavior of alternating current as we understand and use it.

As well, if you think about it: In industries where something like the potential directionality of a signal cable would be literally life-or-death critical, there is no concern for any manner of « diodicity » in cables. I’m talking here about the millimeter-wave communications industries that inform and supply military, aerospace, and surveillance activities (from which we not only derive some of our cable technology, but from which we also subcontract some of our cable manufacturing).

If there were any industry or activity that would benefit most from this otherwise arcane and esoteric knowledge of wire directionality, it would be the industry and activities surrounding signal transfer in military, aerospace, and surveillance disciplines.

All of this to say that, in my own opinion, the idea that wires are actually directional seems to be bunkum, and the idea doesn’t seem to stand up to the light of mild scrutiny.

So the next time you buy a cable with arrows marked on it, or the next time someone tells you « we listen for directionality of our cables before marking them with pretty arrows, » … think about what I’ve told you here and ask yourself whether or not those arrows and the associated claims are just marketing words and concepts aimed at convincing you of something magical that probably isn’t true, because it probably can’t be true.


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