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Voltages move molecules?

  1. Jan 19, 2005 #1
    I was involved in a hot debate about burning-in of audio cables. It's a line that many cable manufacturers have used for years and years, and they basically tell unsatisfied customers "You have to use the cables for over 200 hours before they become accustomed to playing the sound"...

    Now, I was saying it's crap. But that's just some background, the real question here is all about physics. Someone else said:

    Now, I don't know a ton about how voltages can move molecules. So what I'm asking is:

    1) Is this even true? Can voltages 're-align' molecules? What exactly is 're-aligning'?

    2) Originally I assumed that electrons were the only thing that really mattered in carrying a voltage...is this still true?

    3) Even if this person is right, would it be wrong to assume that any movement caused by the electrons would be near completely insignificant compared to the movement caused by, say, a person bumping the cable and making it sway? It seems in my mind that even if the voltage does cause the molecules to move, that even a slight physical disturbance such as a hand or an air vent would completely un-do any sort of organization that occured from the 'stress'. Are these invalid assumptions?

    Also, what is a 'stress'?
     
  2. jcsd
  3. Jan 19, 2005 #2

    GENIERE

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    The manufacturer is probably correct in stating the performance would improve with use. Years ago I did some very minimum studies on the “triboelectric effect” in ECG cables. Basically triboelectric refers to static electricity produced by rubbing dissimilar materials together. The rubbing of the wires (copper, gold…) upon the insulation does produce measurable static fields that in turn generate small currents which I assume would be heard as a background hiss. I can only guess why a cable would improve with age, so I’ll leave it at that.

    [edit]A possible reason for the cable to generate static fields is that the inductance of the stranded wires within the cable would cause movement (microscopic) and the rubbing effect even if the wire was securely attached to a supporting surface.

    ...
     
    Last edited: Jan 19, 2005
  4. Jan 19, 2005 #3

    chroot

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    So-called "electromigration" is a significant problem in semiconductors. The flow of electrons through very small metal wires inside integrated circuits can actually dislodge metal atoms and slowly erode the wire to the point where it breaks the circuit.

    In a wire the size of a Monster cable for speaker wiring, electromigration has absolutely no observable effect. Neither does any sort of "realigning of molecules."

    Basically, if the wire needed burning in, the company would burn it in for you, to avoid complaints. However, it doesn't. They tell this hocus-pocus to the initially unsatisfied customer. The customer, believing the company, listens to his music for quite a while, and slowly becomes accustomed to the sound. Chances are, after a few dozen hours, the customer will no longer even really be able to remember what his gripes were. The company succeeds in preventing another return.

    Neither the ear nor the brain is sensitive enough to hear any sort of difference that speaker cabling could cause. Besides, if you're doing 80 mph beside a semi truck making 90 dB of road noise, do you really think your speaker cables matter?

    - Warren
     
  5. Jan 19, 2005 #4

    GENIERE

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    The link below provides more info re: speaker cables than I think anyone would want to know. The writer agrees with Chroot.

    http://www.audioholics.com/techtips/audioprinciples/interconnects/truthcablesinterconnects.php

    Rod Elliott:

    “Beware! If there is any suggestion that the cable needs to be 'broken in' before you hear the difference, the salesperson is lying! At this point, you should immediately let them know that you know that they are lying, and leave the shop. Cable 'break-in' is a myth, and is perpetuated by those with something to hide - no-one has ever been able to show that there is any scientific justification to the claim, nor shown that the performance has changed in any way whatsoever. Cable break-in is real, and occurs between the ears of the listener - nowhere else (most certainly not in the cable).”

     
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