Cable directionality


I'm sure this has been discussed before but I missed it, so what is all this stuff with the direction of voltage flow with cables? Every cable you see any more has a little arrow on it. Since the signal is AC and travels one direction as much as it travels the other, what difference could this possibly make. I have talked to numerous co-workers (all electrical engineers) and they ALL say this is the biggest bunch of bunk they have ever seen. Since I am the only "Audiophile", I try to keep an open mind(I'm also the odd man out being mechanical.) Skin effect, resistance, capacitance, etc. are true issues. You pass power through a wire and it creates a magnetic field. You do deal with impedence and synergy with the driving source. How about a few technical answers from the audiophile community.
bigtee
I've wondered a bit about this myself. The only logical conclusion I can come up with is that the dielectric does change with electrical flow. If this is true (I have no conclusive evidence that it is), then cable break in (which changes the dielectric) should be performed in the same direction that the cable is to be used. Could you go either way and get the same result? In other words use the cable in the reverse direction, as long as you were consistent? I would think so. I have heard (or read) from Synergistic somewhere that they determine the direction by listening to the cable. There are some theories about eddie currents in cables, but I know little about this and would really like to hear from a cable manufacturer. Is the arrow absolute, or just a way to continue to use the cable in a consistent manner? In other words, are we dealing the dielectric effect or the actual wire?
I posted this some time back. If you search the archives you'll find many spirited answers. (I'm an old EE and don't understand it either.)
Marty: There should be no DC on any of your cables. Music is only ac.
One person said it was because only one end of the shield is connected and that should be the source end.
The cable will have two inner conductors and the shield isn't terminated to the ground connector at the source side of the cable. I've seen this illustrated in some pro audio books when going from ballance (xlr/trs) to unballance (rca/ts) terminals. Hope that helps. Rich
Rich, A lot of cables are terminated with both ends of the shield connected. I have a couple of pairs of Tara Labs that are and have seen others. Recently, I have seen where manufacturers are advertising in their white pages that the shield is connected at one end only. I know with a lot of equipment, the shield is ultimately tied to ground of the unit which in turn is tied to the home grounding scheme. To me, this cable thing seems like an episode of the X-Files.
The shield is typically connected at source end in pro applications. Allegedly helps keep interference away in long cabling situations.
If we coin a word, "directionality", to mean which way does the cable sound better to our ears, then we can do away with manufacturers' marketing hype. However, WHY should a cable sound slightly different depending upon which way it's connected? Unless the shielding on one end counts (electrically)...