I'm not the only one who laughed at the association between units of capture cross section and "betting the farm" am I?
Okay, I probably am. That's okay.
(The capture cross section unit is "barns", as in "broadside of a barn")
You do realize that we really should get a life, no?
John
I recently posted about a rendition by Jacob Collier and his violinist mother of Skylark, the Hoagy Carmichael tune, on the occasion of Jacob's 22nd birthday (August 2). Suzie takes some liberties, but both of them get a tritone interval in the bridge in accord with the sheet music, which practically no one else does. A friend said now she would have to go back and listen to a recording she produced of the tune with another singer to see if he got the interval correct.
I commented later that the world was coming to an end, but that this stuff was really important.
I think there was a boat at some point? Can't remember, it's been too long. Probably across the planet by now.
Richard,
Your models for skin effect are entirely useless as true models.
That said, you stated up front the purpose was to convey to a layman what is going on. As such, the wire drawing does kind of convey the frequency vs depth profiling of skinning. The problem would be, the core of the wire will have no energy stored at frequency whereas the inductor depiction implies such. To try to discuss the effect using that model carries significant physical error. I would prefer a model which is accurate, but that won't be understood by your target audience.
The toroid effect, hmmm..I suspect is not any better, you're depicting local current constriction caused by field enhancement, I suspect the effect is quite different.
Without sleep to speak of, I have to defer to another time on that one.
John
Your models for skin effect are entirely useless as true models.
That said, you stated up front the purpose was to convey to a layman what is going on. As such, the wire drawing does kind of convey the frequency vs depth profiling of skinning. The problem would be, the core of the wire will have no energy stored at frequency whereas the inductor depiction implies such. To try to discuss the effect using that model carries significant physical error. I would prefer a model which is accurate, but that won't be understood by your target audience.
The toroid effect, hmmm..I suspect is not any better, you're depicting local current constriction caused by field enhancement, I suspect the effect is quite different.
Without sleep to speak of, I have to defer to another time on that one.
John
I'm kidding of course, but I'd keep up good relations with the cooks on Vogon destroyers in the meantime.
Really Randy, that's at the least an unfair question (SY would use stronger words). Many here, me among them, have explained, referred, analogued and with other means explained the issues surrounding perception.
If this would be a serious question it throws a bad light on your understanding of these issues.
If it is not a serious question, more meant to stoke the fire, maybe SY's nomenclature is more fitting.
Jan
Attachments
Sounds to me like you never read any of BP's writings...
Please define "soul" in this context?
.... like my 6 x AD815s in bridged/parallel 30W tweeter power amp
Jan
Not heard of that one. I approve though
This is one of my benchmark songs to determine overall sound quality, and the next song on that album 'crying to be heard' is actually one of the driving forces behind my attempts to improve sound reproduction. Any system this song sounds right on will be good enough for me.
This being said, there is a relationship between imaging and this song. A good system will draw apart all instruments and voices and separate them from each other in space. If a system falls short in this respect, the above mentioned song can sound awfully distorted. Only on a discriminating system, it will become apparent how well this album was produced.
The prerequisite for good imaging, I found, is that the loudspeaker acts as much as possible as a point source for all frequencies. Which, of course, makes perfect sense if you think about it. Most speakers fall short in this respect.
Further comments.....that vocal excess sibilance and excessive splash on cymbals is signal polarity dependant, and this can be a confounder when comparing records (CD), even tracks on the same record (CD).
I run Foobar player with a signal polarity switching plugin.....very useful/must have.
Zobelling each of the speaker drivers and another zobel across the loudspeaker input terminals also goes a long way to curing the problem.
Another very interesting finding of mine lately is that I can dictate the sound of my Android player by briefly charging from a Powerbank via a USB cable fitted with choice of filters.
You want dead clean and virtually no excess sibilance, no problem.
You want ferrite sound, no problem.
You want 'party' sound, no problem
.Dan.
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Further comments.....that vocal excess sibilance and excessive splash on cymbals is signal polarity dependant, and this can be a confounder when comparing records (CD), even tracks on the same record (CD).
I run Foobar player with a signal polarity switching plugin.....very useful/must have.
Zobelling each of the speaker drivers and another zobel across the loudspeaker input terminals also goes a long way to curing the problem.
Another very interesting finding of mine lately is that I can dictate the sound of my Android player by briefly charging from a Powerbank via a USB cable fitted with choice of filters.
You want dead clean and virtually no excess sibilance, no problem.
You want ferrite sound, no problem.
You want 'party' sound, no problem
Dan.
How do your ferrets sound?
But more seriously... how about some audio files, or diff. files, or something to illustrate what these different sounds mean?
Richard, as a follow up...
Your wire drawing is totally incorrect at low frequency. Consider at DC there is a uniform current density through the conductor. The magnetic field is zero at the center, so no energy storage due to magnetic field. You on the other hand, drew in a larger inductance at center. Definitely in error with respect to reality.
So I essence, your model is no good at all for all audio signals.
Think of it this way.. All conductive materials will fight time varying magnetic fields, they do this by eddy currents. In a wire, the eddies push the time varying current to the surface.
The systems try to have the least amount of energy, in the case of a round wire, it is the energy that would be stored by the 15 nH/ft inductance of the wire. In a parallel wire pair, what we call proximity effect is the same thing, but there it pushes the currents towards each other, and closer currents store less magnetic energy.
John
Your wire drawing is totally incorrect at low frequency. Consider at DC there is a uniform current density through the conductor. The magnetic field is zero at the center, so no energy storage due to magnetic field. You on the other hand, drew in a larger inductance at center. Definitely in error with respect to reality.
So I essence, your model is no good at all for all audio signals.
Think of it this way.. All conductive materials will fight time varying magnetic fields, they do this by eddy currents. In a wire, the eddies push the time varying current to the surface.
The systems try to have the least amount of energy, in the case of a round wire, it is the energy that would be stored by the 15 nH/ft inductance of the wire. In a parallel wire pair, what we call proximity effect is the same thing, but there it pushes the currents towards each other, and closer currents store less magnetic energy.
John
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I'm getting to that bit, right now I'm having enormous fun with this and trialling on different PB systems.
That and differing flash memory files.
Dan.
Maybe the point of confusion has to do with the fact that, neglecting the effects of eddy currents, any electrons that happened to be traveling at the center of the wire would be encircled by more lines of flux than electrons more near the outside of the conductor?
Maybe to further illustrate the point as an approximate thought experiment, suppose we took a piece of wire and cut the end off square, so we have a surface at the end of the wire that any charge flowing through the wire must pass. If we attach a piece of litz wire to the surface with equal current flowing in each strand of the litz, then electrons entering the solid wire would be uniformly distributed coming through the surface. Suppose we ramp up the current over time, so that we have some di/dt. How would the electrons in the solid wire redistribute themselves given the new ability to do so?
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Not sure. However, given the symmetry, the center of the wire sees no flux. Richard is just trying to show decoupling of the center as a result of frequency. Unfortunately, using inductors to show that may look reasonable at first glance, but they are inconsistent with low frequency actuals. Given that audio is for the most part low frequency, I can see only more confusion by using a bad model.
John
Edit: your Litz thought experiment is actually reality for me. When multiple supers in a cable are soldered at the end, we do worry about distribution by wire. The solid wire currents wil redistribute, but the Litz will also not carry uniformly due to the drops in the metal at the interface. I have to make lap joints about two inches long so that the solder resistivity allows equalization.
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