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Cable Burn In with regard to Audio Directionality.

Discussion in 'Sound Science' started by oldmate, Jun 12, 2015.
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  1. Steve Eddy

    You're a real piece of work, Krueger.

    Does anyone here understand what the hell this clown is yammering about as it regards my reply in this post?

    http://www.head-fi.org/t/771267/cable-burn-in-with-regard-to-audio-directionality/135#post_11733711

    If you do, please try and explain it because as far as I can tell, it's just a bunch of gibberish in an attempt to weasel out of owning up to the nonsense of his previous post.

    se
     
  2. Steve Eddy

    You don't have to saturate the core. The B-H curve is nonlinear through all ranges. And who limited the discussion to interconnects only?



    So? What has this to do with the subject being discussed?


    [qote]There is an interesting effect where placing a current-carrying wire inside a static magnetic field will cause a measurable increase in its resistivity by forcing the current towards one edge of the conductor.

    You can also measure the voltage drop in a conductor that is in a static magnetic field due to this, along a line across the conductor that is perpendicular to the direction of the flow of current. But again, this takes a high current density and a very strong magnetic field.

    It is highly unlikely to have any effect on normal audio cables.
    [/quote]

    And like skin and proximity effect, it would be linear. We're talking about nonlinear distortion.

    se
     
  3. arnyk
     
    Sounds like a fragmentary understanding of nonlinearity.
     
    At very low levels a typical real world nonlinearity is well-approximated by a straight line. IOW,it acts like there no nonlinearity at all. Of course the nonlinearity is there, but it takes some serious stress testing to find it with measurements.
     
    That's why trying to measure the nonlinearity of a piece of miniature coax like RG 174 came out the way it did - the measurements showed very little (clearly inaudible) nonlinearity.
     
  4. Steve Eddy

    *yawn*



    What sort of gibberish is this? "A real world nonlinearity"? We're talking specifically about a specific ferromagnetic material.



    You obviously didn't read what I wrote. I said the only distortion in the plot was the residual distortion of the AP rig.

    se
     
  5. Exacoustatowner
    Peacemaking? As I understand it (no EE degree-just University level physics class on electromagnetism and Quantum Mechanics in the days of yore) the argument is whether or not nonlinearity can be caused by external magnetic fields acting on ferrous materials. My simple minded reading of literature on the subject shows that it can be but it is not in the realm of audibility. Hence my spoofing and fake "audiophile solutions" which evidently HAVE been used by the Snake Oil crowd.
     
    You both seem to agree that in any situation involving audio cable it won't be audible. Steve posted a PDF showing measurements on three different cables that appear to be the same.
     
    So personal insults aside- is there any real disagreement on the science? 
     
    Are there measurements showing that if the magnetic field is sufficiently strong it will cause audible effects? Do you need the sort of magnetic field generated by an NMR? Perhaps I should go to work next week and wrap some audio cable around the NMR in the lab and listen to some earbuds? :) I do have access to an NMR and I AM kidding about wrapping audio cable around it.
     
     Then we have a new vastly expensive audiophile solution that can't be used around pacemakers! Deliberate creation of non-linearity that some find pleasing to the ear? (JOKING)
     
  6. Exacoustatowner
    Here you go. A Patent for audio cable that eliminates the magnetic interference affecting audio quality! https://www.google.com/patents/US6974906
     
  7. arnyk
     
    Yes. Steve seems to entertain himself by twisting my posts beyond belief to create non-existent errors, while making and then trying to distract attention from his own major gaffes like this:
     
    http://www.head-fi.org/t/771267/cable-burn-in-with-regard-to-audio-directionality/135#post_11733787
     
    "A static magnetic field won't have any effect on an audio signal."
     
    Which as I documented, fails to include the potential consequences of the Hall Effect which involves static magnetic fields. The Hall Effect is used to measure static magnetic fields by measuring its ability to modulate audio signals. 
     
    https://en.wikipedia.org/wiki/Hall_effect_sensor
     
    Even says that the Hall effect can be used to create a digital switch for audio signals.
     
  8. arnyk
     
    It is well known that audio gear with multi-turn windings and ferrous cores (transformers, inductors, and electrodynamic speaker drivers) can have audible distortion and losses due to internal magnetic effects. Building these with steel-cored wires could cause problems, so this is avoided.
     
    The magnetic field strengths in audio components are usually far less than one finds in a NMR device, but also far, far greater than one finds in an ordinary audio cable.
     
    High powered speaker drivers operated at very high SPLs may be an exception. NMR magnets are exceptionally strong partially because the area they magnetize is relatively large. There can be highly concentrated fields in speakers, but they are tightly focused on relatively small areas.
     
    Signal cables often include steel or iron wires to improve their mechanical strength. Cable systems generally include steel cored wires and cables even though the systems are highly sensitive to IM distortion because of the many concurrent different frequencies that they operate with. There is no problem because the magnetic fields are so weak. 
     
    Audio cable elevators are an example of audiophiles taking a potential effect way beyond any logical real world situation. 
     
  9. arnyk
     
    Simply putting both wires of a cable in close physical proximity to each other, which can be easily done by twisting them together or making them into a coaxial cable addresses this concern.
     
    Both coaxial cables and twisted pair are widely used for this reason.
     
  10. kevin gilmore
    not even close to true
    http://gilmore.chem.northwestern.edu/oxford500.jpg
     
    11.7 tesla
    the core weighs in at about 800lbs, 25 miles of wire
     
    active field in the center of the core is only 5mm wide and 3cm vertical
     
    whole body nmr's are a completely different thing, and run at much much lower field strength.
    even then, the active field is 1 foot in x and y and about 3 inches in z
     
    twisted cables when checked on a time domain reflectometer show all sorts of
    issues with respect to accuracy of number of turns per inch, and any bend in the
    cable causes more trouble
     
  11. Steve Eddy

    Where's the gaffe? Exactly what effect does it have on the audio signal? If I tape a bunch of magnets to a length of cable, what am I going to see at the output that is different from the input?



    Tell me bright boy, how does something that is static, modulate anything? Do you understand what "static" means? Do you understand what "modulate" means?

    It doesn't seem that you do.

    se
     
  12. castleofargh Contributor
    I'm way over my head, but wouldn't we still end up with something we could count as an increased overall impedance?(be it magnet or ferrite stuff or even shielding)
    I imagine the magnetic field created by the music(AC) inside the wire would be affected by the magnet. sure the magnet has a static field, but the wire doesn't. so I'm guessing that might alter some of the induction part(not that it would be much in a headphone cable).
     
     
     
     
    that was, castleofargh doesn't know how to science. [​IMG]
     
  13. Steve Eddy

    Technically, the magnetic field would alter the charge distribution in the wire, somewhat akin to proximity effect, resulting in some microscopically small increase in the wire's resistance. But it wouldn't have any effect on the signal itself except for an equally microscopically small amount of linear attenuation.



    Not quite sure what you're trying to say here, but it wouldn't alter the inductive properties of the cable, except for the presence of any ferromagnetic material in close proximity used to create the static magnetic field.




    Just remember to hold on tight. :p

    se
     
  14. arnyk
     
     
    Yet another intentional misreading of my post.
     
    When someone mentions a NMR without any other qualifications, what are thy referring to?  Common sense would lead one to believe that they are referring to the most common form of a NMR machine which is a whole-body NMR.  Sue me for using common sense!
     
  15. arnyk
     
     
    The gaffe was saying that there is no effect.
     
    The size of the effect depends on the strength of the magnet and the conductive material. As stated in the Wikipedia article that I linked, a really strong magnet acting on the right kind of electrical conductor can make it act like a electrical switch or if you will an audio switch.
     
    In the case of audiophiles taping common household magnets to the a copper cable, there might be a tiny measurable effect, but an audible effect is exceedingly unlikely.
     
    However, you didn't mention audible effects Steve, you said that there would no effect.
     
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