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Old 23rd January 2013, 09:25 PM   #33411
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Quote:
Originally Posted by DF96 View Post
You may choose to call them eddy currents,(the author chose to) but the net result is that the current density is everywhere sinusoidal at the applied frequency.(the proximity driven currents are proportional to the drive current slew rate) The geometric distribution depends on frequency alone. For non-sinusoidal waveforms Fourier and superposition is all that is needed.


Yes, in order to be able to obtain an analytic solution. This simplifies the maths by eliminating skin effect; it doesn't change the physics.(never said it did. You stated depth vs frequency, the author didn't, but used thinshell)

I have never met any of these gentlemen, so I have no idea what they think or whether they have the same misunderstanding as you.(it's not a misunderstanding, they can't duplicate the simplicity of your argument when characterizing proximity losses at varying slew rates. The best most can do is emperical values.)

So far, the only peer-reviewed paper you have produced to support your claim actually completely destroys it.(actually, claiming such doesn't mean it is so. As the authors stated up front, they simply used the integrated form with no intent to determine redistribution as time varying.). I must admit I was puzzled when you offered the link, but I did wonder whether you might have misunderstood the paper. It seems you did.(see last statement.. starting with an assumption doesn't mean the assumption is rule)

Please don't keep reasserting ideas which are false. Find some genuine supporting information, or admit that you are mistaken (sheesh, the first person to even try the test finds 2nd harmonic in the result, but I guess test results mean nothing. Let's convince Ed to drop the resistor value and try again..) .
btw, I certainly am finding lots of proximity modulation for organic pores and magnetic proximity resistive detectors..sometimes, google is your friend..other times...

jn

Last edited by jneutron; 23rd January 2013 at 09:28 PM.
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Old 23rd January 2013, 09:33 PM   #33412
DF96 is offline DF96  England
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Quote:
Originally Posted by jneutron
As the authors stated up front, they simply used the integrated form with no intent to determine redistribution as time varying.
Where do they state they had no intention to determine a time varying distribution? There is no hint that I can see that they thought they were using a time-averaged form anywhere. Please identify their statement which you believe says this.
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Old 23rd January 2013, 09:41 PM   #33413
fas42 is offline fas42  Australia
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There are vast numbers of postings in this, and the previous thread bemoaning that the standard measurements don't give enough of the story to know what will "work" and what won't. Yet rather than focus of how to extend the measurement regime to get more useful numbers, to be more able to predict the real world performance of an actual product, the conversations grind on and on and on about the same old, relatively easy to produce, numbers, debating the merits of their relative sizes.

The sting in the tail always is, of course, a fairly general agreement, as an appendix to the discussion, that those numbers mean very little in the subjective world of audio.

Talk about wasted energy - if I come back here in 5 years time will I see exactly the same conversations occurring ... a "song" playlist on endless repeat ...

Frank
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Old 23rd January 2013, 09:48 PM   #33414
DF96 is offline DF96  England
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Quote:
Originally Posted by jneutron
the author chose to
I can't find the term "eddy current" in the text. Are we reading the same paper?
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Old 23rd January 2013, 09:59 PM   #33415
jcx is offline jcx  United States
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I have suggested putting distorted music through a good psychoacoustic encoder to see what the model chooses to keep in the compressed file - surely most of what the psychoacoustic compression encoder wastes bits on is more likely to be "clearly audible"?



the Filipović paper does explicitly invoke superposition - implying Linearity of EM is a base assumption - may be hard to find papers that don't use it to frame the math

I did run across Giulliani "On electromagnetic induction" 2001 several versions, the 2009 publication costs money - he adds in the Lorentz force term which I think should then model "ordinary magnetoresistance" (rot = curl was confusing)

Last edited by jcx; 23rd January 2013 at 10:14 PM.
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Old 23rd January 2013, 10:01 PM   #33416
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Where do they state they had no intention to determine a time varying distribution? There is no hint that I can see that they thought they were using a time-averaged form anywhere. Please identify their statement which you believe says this.
""Currents of angular frequency ω and r.m.s. value I""

Quote:
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I can't find the term "eddy current" in the text. Are we reading the same paper?
J2 is eddy currents.

jn
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Old 23rd January 2013, 10:06 PM   #33417
SY is offline SY  United States
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Quote:
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Talk about wasted energy - if I come back here in 5 years time will I see exactly the same conversations occurring ... a "song" playlist on endless repeat
That's because it's not a technical discussion where evidence answers questions with finality. This is about fashion and faith, which are incapable of being decided. Russell's criticism of Aquinas comes to mind.

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He does not, like the Platonic Socrates, set out to follow wherever the argument may lead. He is not engaged in an inquiry, the result of which it is impossible to know in advance. Before he begins to philosophize, he already knows the truth; it is declared [by his faith]. If he can find apparently rational arguments for some parts of the faith, so much the better; if he cannot, he need only fall back on revelation.
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Old 23rd January 2013, 10:12 PM   #33418
DF96 is offline DF96  England
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Quote:
Originally Posted by jneutron
""Currents of angular frequency ω and r.m.s. value I""
That is defining the total current. No time integral is stated or implied. To define a sinusoidal current you need to specify its frequency and amplitude. This they do. Amplitude for AC currents is usually specified either as peak or RMS. They use RMS.

It is slightly puzzling, as EM theory usually uses peak current, but it has no significance for what you are saying. So there is nothing in the paper to say that they are using a time average. This is, of course, because they are not using a time average.

Quote:
J2 is eddy currents.
That may be so, but the authors do not say so; your assertion that they do is therefore false. However, we are not arguing about what something is called but what it is.

You are going to have to try harder.
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Old 23rd January 2013, 10:13 PM   #33419
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It may turn out that the information derivable from measurements and the information derivable from formal listening are separate, but hopefully related, interpretations of a third underlying function. I sometimes interpret what John Curl is trying to teach here as a plea to study the underlying function for its own sake. Topology, ancillaries, intrinsic properties, etc.

And, although it's almost an object of faith, where has it ever been shown that because an effect has very small numbers, maybe even below the noise floor, that it must be inaudible? That looks plausible, but it lacks foundation.

Thanks,
Chris
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Old 23rd January 2013, 10:21 PM   #33420
SY is offline SY  United States
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Originally Posted by Chris Hornbeck View Post
And, although it's almost an object of faith, where has it ever been shown that because an effect has very small numbers, maybe even below the noise floor, that it must be inaudible?
It hasn't and it can't be, as a matter of logic. What can be demonstrated, in principle, is the audibility of some of these asserted "problems." What data exists don't demonstrate it (beyond well-known variables like frequency response, level, clipping, gross distortion...), and the folks who assert it are singularly unwilling to provide anything beyond "because I say so and I got some nice reviews in a magazine."

Once something is shown to be audible, then there's data to work with, otherwise people would be wasting a lot of time chasing after ghosts when any nut-ball with a keyboard can claim that (for example) the direction of wire makes night and day sonic differences to anyone who isn't deaf.
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