I need help on directionality of speaker cables

No offence, but I think a few members really need to do a bit of basic reading on electronics to understand AC and DC current.

Without getting bogged down here, DC (direct current, or fixed polarity) is what takes the information from source to preamp, preamp to power amp, down digital cables etc. AC (alternating current, which constantly reverses polarity at either fixed or variable frequency) is what brings mains power to your system, and what carries the final signal to your speakers. I believe it's also what carries the signal from a TT cartridge.

Polarity is VERY important in DC circuits, and there is some evidence that such cables can perform better using directionality, especially where filtering is involved.
However, there is simply no point in directionality in AC cables, as there is no fixed direction of current flow, and hence no true polarity. The only reason we have + and - speaker wires (which probably confuses the issue) is to prevent the speakers being wired OUT OF PHASE with each other, which is detrimental to the sound to say the least!

As someone above pointed out, the only possible reason is if the cable has shielding and this needs to be attached to a particular component (eg. the amplifier or TT).

It would be refreshing to read something more creative than "try listening and you'll hear a difference" every time another member actually uses physics or electronic theory to back up an answer. Sometimes this forum gets a bit "Evolutionists vs Creationists"!

As far as I'm aware, the output stages of CD players, tuners and preamps is DC. That's why the power supplies of such devices turn your wall outlet AC into low voltage DC to do their work. It's only at the output stage of the power amplifier where the signal becomes AC again, as it must to move the voice coil back and forth like a piston in your speaker.
Given that the negative outer ring of the in & out RCA sockets on amps etc are all connected to the chassis (earth), this says to me it must be a DC circuit. I'm yet to see the (-) of a speaker terminal on the power amp earthed to the amp's chassis.

Turntables, by virtue of their moving magnet or cartridge are basically a speaker in reverse (as is a microphone) hence their AC output.

Analog and AC are unrelated terms.

My post wasn't meant to sound arrogant, it was more about the apparent muddling of AC and DC in some posts, and less about the detail of what each component does. As always, I am happy to be set straight by an EE if the above is wrong.

If analog audio is AC, then doesn't that also defeat the purpose of direcional arrows on interconnects as well as speaker cables?
My understanding was that audio signals could be carried as DC, but that AC was required for speakers to allow them to vibrate in piston fashion.

I can see I'm going to have to have another discussion with my info source (a digital engineer) to straighten out my knowledge!

I humbly backpeddle for my previous grandstanding...

"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."

Ryder, where is this info from? The reason I ask is that a digital signal, by it's very nature, doesn't have frequency in the way analog signals do. As I've quoted above from a reputable book on electronics, a digital waveform is a DC signal that varies between zero volts and a max volts, with no in-between.
Skin effect, whilst it exists in analog transmission (especially video), is not relevant in digital data. That's why HDMI and digital RCA cables don't need to be silver-plated copper. The bitstream of digital data is either 0's (zero volts DC) or 1's (eg. +5 volts DC). The quality of the cable will impact on how much data loss or errors occur, and can cause timing errors, but it isn't carrying any frequencies as such in terms of audio or video frequency.

The only time you really need to consider the 'skin' effect is when using analog video, such as S-video, component etc.

Quoting directly from "Electronics for Dummies" page 222, here's a bit on digital waveforms...

"Digital Waveform: A DC signal that varies between no volts (low) to some pre-determined voltage (high). The digital circuitry interprets the timing and spacing of the high and low marks."

I've also confirmed that the current carried to the speakers is indeed AC.
I'm still trying to find something difinitve regarding the signal from source (eg CD player) to amp.

Ah yes Ryder, but from the Wikipedia link you posted: "The skin effect is the tendency of an alternating electric current (AC) to distribute itself within a conductor so that the current density near the surface of the conductor is greater than that at its core."

Even this notes that the skin effect is specific to AC current.

Transmission of digital data, as I quoted from the electronics text, is DC.

Put these two facts together and "skin effect" is not relevant to digital data transmission, and so cables for such DC digital data do not need to take it into account.

QED.

Ryder, I think you just hit the nail on the head with one of the ongoing flaws with forums like these.

Despite the fact that electronics and physics theory have been studied, researched and set in stone for longer than most of us have been alive (and are what the design and building of all cd players, DAC's, amps etc are based on), too many audiophiles are very quick to flipantly disregard these laws because either:

1. They believe they can hear (very subjective) some difference in sound, or
2. A manufacturer of some new product who stands to profit (and let's face it, it's usually a cable of some type) makes dubious claims based on their own "research" to sell said product, and we believe them.

I totally agree we need to trust our own ears as to the sound we like (subjective again), but that can never be a reason to disregard proven electronic and physics theory, especially when some of these cables are sooo expensive.

Allowing a cable company to tell you that it's AC-carrying speaker cables are directional, or that a DC-carrying digital connection utilizes the skin effect for improved transmission is marketing baloney.

I promise to make no more posts on this thread!