I need help on directionality of speaker cables

Depends whether you bought the cables new or used. I bought my Nordost SPM cables brand new, and they suggested either way is fine, but after sticking to the direction of flow for a certain period you have to continue running in that direction for best results. I've used mine with the arrows pointing from the speakers to the amp.

If you bought it used, it's best if you find out from the seller which direction he had adopted.

Bob,

Since you've called upon me, I've to do a bit of homework. A quick search got me to an article by Stereophile written by Robert Harley on the effects of cable directionality in digital cables. To summarize, he not only heard a difference in sound directionality but had done measurements to see the RMS jitter drop when he reversed the cable direction. He did the tests five times each on three different cables.

http://www.stereophile.com/features/368/index3.html

The measurements done confirmed the reports of the critical listeners that digital interconnects sound different when connected in different directions. There are many interesting variables mentioned as well in affecting the directionality such as how the two RCA plugs were soldered to the cable, any bumps or discontinuities in the solder that will cause a change in characteristic impedance etc.

I believe this report may apply to all cables and not only to digital cable.

Another note in Nordost webpage on the importance of cable directionality that some of you may treat as a marketing ploy.

http://www.nordost.com/faq/morefaq.cfm?startrow=3&maxrows=2

I would rather not to comment on whether I heard a difference when I changed the directions of my speaker cables as this may be like asking a question of whether you would hear a difference with power cords. I would suggest to try it out yourself and see. IF you can't hear a difference that let that be it.

Bob, then can you elucidate me on how the 'stream of information' is carried to the next stage if they don't carry AC signals? Signals in the form of electrons still need to pass through the cable isn't it?

Ryder, The stream of information is not AC and not analagous to the voltage information before encoding into digital, i.e. numbers. The numbers (information) are carryied to the next stage and then decoded back into an analagous varying voltage + or - and amplified to drive the speakers with AC current.
Bob P.

Bob, please treat this as a healthy discussion.

I am confused by your explanation. We all know that the bits are in ones and zeros(information). The question that remains is whether there is current flow in the cable. I have read from sources that AC current do flow in digital cables. Before this I had known that there must be some current to transport those bits(information) to the next stage.

Your argument is that AC is non-directional. If that's the case, how do we explain on the findings by Robert Harley in Stereophile? My logic is simple. If what he wrote is true, then this will apply to speaker cable as well. By the way, it's AC current in speaker cables am I right?

I would be glad as well if any EE would care to clear things up for us.

To the interest of the original poster, if you would care to google on "cable directionality", there are quite a few sites that touch on this article, mostly cable manufacturers. It's interesting to note of Russ Andrews claim of having verified the benefits of cable directionality with their engineers using advanced equipment and technology, but unfortunately didn't provide any technical evidence to back that up.

In the transmission of the signal in digital cables, electron travels down the cable at the frequencies used by audio/video signals. The higher the frequency of the signal, the more this signal is pushed to the surface of the cable, and the skin of the conductor itself carries a considerable portion of the signal. This phenomena which is called skin effect is a tendency for AC current to flow mostly near the outer surface of the solid electrical conductor at frequencies above the audio range.

In skin effect, the effective resistance of a wire is increased for AC current at moderate to high frequencies compared to the resistance of the same wire at DC current and low AC frequencies. In other words, both AC and DC current exist in digital cables.

I think the issue we need to be certain of here is whether we can really correlate AC current, which is non-directional, to the debate of directionality of cables. There may be other variables that may be overlooked.

On a separate note, I have always followed manufacturer's recommendations and never reversed the directionality of interconnects all this while but have once reversed my speaker cables for the sake of experimenting. Frankly I'm not so sure. I thought it sounded little messy, but then maybe it's in my head.

I guess we can kill off this discussion now for what could be just a simple question to the poster.

Oh dear. Looks like most reference material(mostly from cable manufacturers) have misinterpret skin effect in digital cables. But I believe the one stated in Wikipedia is still genuine.

I've just asked one of my colleagues in the same firm who is an EE and without any hesitation said that it's DC in digital. However, when asked about "skin effect" in digital, he said he read it somewhere in the books years ago and not too sure on its function now. When asked about directionality in cables, he's not convinced at all. BTW he has only has a Sony mini compo for his audio system and not exactly an audio enthusiast.

Carl109,

If you would do a search there are abundance of details of skin effect that do occur in digital interconnects, be it SP/DIF or AES/EBU. This is just one out of the many references that describes this.

http://www.psaudio.com/products/xstream_digital_moreinfo.asp

You have to scroll down abit though. I didn't provide any links earlier as I thought nobody would be interested to have a look (since Bob didn't read the earlier link by Stereophile). And just if anyone wants to know more about skin effect, here is the description in Wikipedia.

http://en.wikipedia.org/wiki/Skin_effect

Probably your reference book doesn't mention anything on skin effect in digital cables? Anyways, the main question that remains is whether there is any direct correlation between AC(non-directional) and directionality in cables. There is no definite answer to that I would really like to know as well.