I Is a Copper Conductor Directional?

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The discussion centers around the claim that audio cables can be directional, suggesting that the electrical conductivity differs based on current flow direction. Participants argue that this notion lacks scientific backing, with many asserting that the idea is rooted in marketing rather than engineering principles. The consensus is that high-purity copper is isotropic, and any perceived differences in sound are likely due to placebo effects rather than actual electrical properties. Some mention that manufacturers use directional arrows on cables, but this is viewed as a marketing tactic rather than a technical necessity. Overall, the conversation highlights skepticism towards the claims made by audiophile communities regarding cable directionality.
  • #31
boneh3ad said:
While we are at it, I should also mention that audiophiles in general have effectively zero grasp on signals processing, specifically the Nyquist frequency and its implications. All of this high-resolution audio BS pilfered by people like Neil Young is pure snake oil.
It's worth noting that as with many audiophile beliefs, there's perhaps a grain of truth to this one. CDs only sample at 44.1kHz, and DVDs at 48, and in practice, it's at least non-trivial to make a brickwall filter that is down to effectively zero at 22kHz but has no phase or magnitude impact on 18-20kHz. There's a real argument to be made that sampling at perhaps 60kHz would make it far less likely for devices to have audible filter artifacts because then you'd have the entire range from 20-30kHz to implement your low pass filter.

Similarly, 16 bit is only 96dB of dynamic range, which means that you have to be a bit more careful with your mastering because if you have a mean level of say -30dB or so, it's possible you could start to hear some of the noise from dithering or quantization (if you have one of the awful "audiophile" DACs that doesn't dither) during quiet sections. This also applies to using digital volume control (say, the windows volume control on your computer) - if you're outputing a digital signal at 16 bits, and you turn the digital volume down 20-30dB, you could start to hear dithering noise during quiet periods (since you have to have more analog gain in your amp to compensate for the low digital volume level). 24 bit solves both of these issues - you could have a 24 bit encoded signal at a mean level of -50dB and the dithering/quantization noise will still be completely inaudible.

Of course, that's not the argument they're using, and with a properly implemented filter (which is definitely possible), 44.1 is definitely sufficient for audibly perfect results.
 
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  • #32
gmax137 said:
Customer on Phone with Service Rep: "Hey, I just spent $1000 on these new speaker cables and they don't sound any better than the lamp cord I have been using..."
Service Rep: "Hmm, are you sure you have them oriented correctly?"
Customer: "What?"
Service Rep: "They have to be oriented correctly: The arrow must be pointing towards the speaker."
Customer: "Wait, let me try that. ... Wow, you're right! I can hear a difference. The sound is more articulate and involving..."

The point is, people want to hear an improvement. The audio companies just give them what they want. If you think the $1000 cables sound better, wait until you audition your buddy's system, he bought the $2000 cables (the gallium arsenide-free version).
I tend to believe that this also is part of the reason why they go on and on about break-in. If it takes a thousand hours before the cables "relax" and sound their best, you've likely completely forgotten what your old ones sound like, and are likely also past the return period.
 
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  • #33
Being hard of hearing offers little cause to rejoice. But this may be an exception. In the case of audio equipment, my hearing cutoff at 2 kHz appears to be a blessing. I can buy satisfactory audio equipment at the dollar store. :cool:
 
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  • #34
I guess that's in the same category as claiming that a gold cable is much better than copper cable, and then there may be a specially gifted guru, who can make that even better only by touching it once with his magical hands. Of course this makes the cable by an order of magnitude more expensive than a normal one, let alone the pure material and frabrication costs, but only such an expensive cable has the promised effect, and this may even be true, because the placebo effect works the better to more expensive a product is.

Another great example is the filter for electricity from nuclear power plants. Just buy this precious device, and you'll be save from getting the very dangerous electric current produced by nuclear power plants.

Also of ustmost importance for you health is to prevent your bottled water from being scanned by the cashier since the interaction of the very dangerous light with the bar code produces very bad vibrations in the water. But it's easy, just buy a special pen with a magical ink to erase the bar code...
 
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  • #35
vanhees71 said:
then there may be a specially gifted guru,
I imagine that there is a team of such gurus, and they are the ones who determine which way the arrow should point. The company can then point to this team and say that "in their expert opinion" there's a directionality to the cable, and if you can't see the emperor's new clothes hear it then the problem is in your ears. I suspect that covers them legally, up to a proper double-blind test of the experts' opinions...
 
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  • #36
Well, the legal aspect is interesting too. Is it fraud to exhaust the superstition of people to ones advantage? As I said, it's an interesting question, but off topic in a physics forum ;-).
 
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  • #37
DaveE said:
No. Just No.
99.999% of the electrical engineering content you find in audiophile sites is BS. It is a community composed of people that think they should pay for Rhodium plated connectors.
Most of us will settle for Gold. :wink:
 
  • #38
Seems it is time to close this thread.
 
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