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Physical/scientific aspects behind cable sound. Discuss. - Page 2

post #16 of 87
Great discussion. I was thinking about this very issue this week. I agree that many of those mfg links have definite marketing-speak about them, especially the one already highlighted.

Additionally there seems to be a clear (and valid) desire for people to look at this from an engineering point of view, but I think the spirit of the original idea is to get at the actual physics/science underlying the differences in various cables.

While it is true that such discussions are not by nature exhaustive, since the field is as insanely complex as any other, I am in the camp that believes we can make some progress!

So, as they say in physics, let's consider the spherical cow here. Can we boil this down to something simple to start? Let's talk wires.

We've got electrons "flowing," which is really a way of talking about transfer of energy between adjacent atoms in a strand of 1-atom-thick "cable." What is an audio signal but the frequency and amplitude (i.e. number?) of electrons that are being moved at a given time?

So to a very very first approximation, let me also for the time being simply neglect energy loss inherent in ANY "real" system. Thus the things that might matter or be subject to optimization would include maximizing our cable's ability to deal with changes and complexity in frequency (speed of electrons moving?) and the sheer number (magnitude) of electrons moved at a time.

Gosh, I am totally pulling this out of my ears, but let's start here. Is this the right way to be thinking about the signal traversing a length of cable????
post #17 of 87
I'd just like to add that though some people hear differences in cables, not all of them, me included, understand how cables work to begin with, just like with most things in this hobby (headphones, amps, etc.) so asking them to explain scientifically doesn't make sense.

Maybe you should give a short explanation of how a cable works, then go from there.
post #18 of 87
post #19 of 87
Quote:
Originally Posted by edstrelow View Post
I doubt that many of the crowd who regularly call "placebo" or cry about the need for double blind testing have any idea of how complicated this area is.
It doesn't matter how complex the technology behind it is.

1. It's audible, or it's not.
2. If it is audible, it either sounds better or it does not.

The engineering that goes into the results might be incredibly complicated, but the end testing fundamentally is the same. Especially when we're not past (1).
post #20 of 87
With all due respect, I think that many may be overlooking a fundamental goal of the original inquiry. If the end is simply a here-and-now good or better sound, then I would be in agreement with the ideas regarding engineering practices.

However it's a fundamental question of what might be contributing to the differences that people detect are, in fact, audible.

(Let me be clear right now and say that I've never been able to tell a difference in cables.)

However, this does not mean that there could not be some difference, audible. For me one of the primary aims of this really nice exercise is to go back to first principles, and with that fundamental knowledge in hand, one may be able to extrapolate or expand upon the idea in order to find a cable/etc (or create one!) that does merit a truly audible difference.

We're just stretchin' out here, that's all. Anyway, I hope the engineers/physics gurus start comin' out of the woodworks on this one. Surely someone has a better background than my lowly bac of years gone past!
post #21 of 87
I know that Dr. Richard Grenier published a couple of very significant articles on this general topic in the Journal of the Audio Engineering Society in the 1980's, but their content is not freely available on the web (it requires membership). I understand that Grenier went into significant detail about how it is really all about the R-L-C values, and explored how there have indeed been many other factors that have been explored (such as skin effect) that in normal circumstances turn out to be 2nd and 3rd order effects that are demonstrably inaudible.
post #22 of 87
Anyone here remember the Bob Carver Challenge. Bob Carver tweak his $600 SS amplifier to be a electrical copy of a $12,000 Conrad Johnson tube amp. The Stereophile experts with a single blind test in their Santa Fe listening room basically gave up trying to figure out the difference.

Placebo effect is of course also very possible for audio perception. For example, the way optic works, we're supposed to see things upside down but the brain correct the perception because we know how thing should be. So if you believe in a difference, you most likely will hear a difference. And if you don't, you never will.

Soundstage is another example of the brain compensating our audible input. Our brain is trying to construct a 3D soundscape with only two sources. This is not consistant, so now we have surround sound.

One of the things I found interesting is many thinks silver wire is bright and gold is warm. Maybe the color determine the perception. A lot of the transistor are connected with either gold or aluminum wire. Can we tell the difference since they are covered by epoxy.
post #23 of 87
Quote:
Originally Posted by dvw View Post
So if you believe in a difference, you most likely will hear a difference. And if you don't, you never will.
That's simply not true. There are many died-in-the-wool skeptics that are now believers. They may be deluded (I don't think they are), but the notion that if you don't believe it, you will never hear it, is just not correct.
post #24 of 87
Quote:
Originally Posted by Patrick82 View Post
After I suspended the cable inside toilet paper rolls and wrapped the rolls in ERS Paper it didn't sound muddy or dull at all, it gave improved dynamics and low-level detail, no weaknesses!
I think you should submit this cable of yours to someplace like Stereophile for exhaustive analysis.
post #25 of 87
Thread Starter 
Quote:
Originally Posted by Febs View Post
I can see that this section of Nordost's website is entitled "Technical Papers," but the actual contents appear to be nothing more than advertising copy.
I think it's all advertising.

Take the 'technical paper' on '90% of the speed of light.'

They claim to have designed the cable such that the permeability and permittivity of the insulation between the cables results in a wave propagation speed of 90% the speed of light.

What does that mean?

Neglecting other effects for now and assuming the mediums are linear, say you had a cable that was 1 meter in length. Given a wave propagation speed of 90% the speed of light, your signal will take approximately 3.7E-9 seconds to reach the other end. Given 80% the speed of light, which is typical for most cables today, that's 4.16E-9 seconds.

For those of you not familiar with scientific notation, that's:

.000000037 seconds @ 90%

and

.0000000417 seconds @ 80%

I don't know about you guys, but I'm not so confident of my hearing ability to tell the difference in wave propagation on the order of one billionth of a second.
post #26 of 87
My feelings here are that most folks are missing an essential point.

The differences between copper and silver conductance might be miniscule, billionths of a second, picofarads, etc., but remember we ain't sticking the end of the cable directly into our ears!

The signal goes through various manipulations in the amp end and these miniscule differences get multiplied millions or billions of times by the op amps, caps, resistors, transformers, transducers etc. etc..

So tiny differences between cables can and do get multiplied in the process as well, to the extent that human ears can hear differences.

Remember we're reading bits and bytes, or the tiniest of vibrations at the source. AND this source material is on the same scale of the electrical differences between cable material and construction. It's that simple.

I don't know what's so difficult about that concept. That's all. 8-)
post #27 of 87
I think we still don't have 100% of the explanation of how our brain work.

When we say "audible", I guess it is part of the brain intercepts and decode certain information and then tell it master it "hears" something. But somehow we have very little understanding when we try to correlate this to music (not just sound) listening.

In the headphone circle, some one talk about "Head Transfer Function" to elaborate of how a sound stage is simulated "between our ears".

Not too long ago I read a book called "Blink" by Malcolm Gladwell. Malcolm spotted experiences to demonstrate our brain can have its own way of working things out, much faster than using rational deduction and reasoning which we are trained at school.

So, measurement of distortions, speed, resistance, capacitances, skin effect, dielectric effect... can all be done in the best of the labs, these do not necessarily explain how our brain decode music and what it filters out in the process. How a piece of wordless music can make touch our heart, make us cry, is way beyond the frequencies, ampitudes and harmonics that we are trying to quantify.

Apparently, very few have worked on this cross-disciplinary area so there is a big piece missing, I would say, before we really understand how music is being heard. Without this, the cable difference will remain a subject of discussion, not conclusion.

FWIW.
F. Lo
post #28 of 87
Quote:
Originally Posted by fkclo View Post
I think we still don't have 100% of the explanation of how our brain work.

When we say "audible", I guess it is part of the brain intercepts and decode certain information and then tell it master it "hears" something. But somehow we have very little understanding when we try to correlate this to music (not just sound) listening.

In the headphone circle, some one talk about "Head Transfer Function" to elaborate of how a sound stage is simulated "between our ears".

Not too long ago I read a book called "Blink" by Malcolm Gladwell. Malcolm spotted experiences to demonstrate our brain can have its own way of working things out, much faster than using rational deduction and reasoning which we are trained at school.

So, measurement of distortions, speed, resistance, capacitances, skin effect, dielectric effect... can all be done in the best of the labs, these do not necessarily explain how our brain decode music and what it filters out in the process. How a piece of wordless music can make touch our heart, make us cry, is way beyond the frequencies, ampitudes and harmonics that we are trying to quantify.

Apparently, very few have worked on this cross-disciplinary area so there is a big piece missing, I would say, before we really understand how music is being heard. Without this, the cable difference will remain a subject of discussion, not conclusion.

FWIW.
F. Lo
My older brother is a neuropsychologist, and though he's an Alzheimer's expert, he brought home many books on perception when he was in college and graduate school and I read them all. (Heaven knows where I got the energy, but then I was in High School at the time) Now I'm not a trained neuropsychologist, but I've some idea of how the brain supposedly perceives.

So I've some idea of what you're trying to say. And I agree for the most part, but I don't think perception is the most important point here.

But I am a trained physicist, though I haven't practiced in years. And the fundamental science doesn't have to be explained in detail, IMHO.

If you look to my previous post, it explains how I think we're missing the most important point. The cables ain't stuck directly into our ears.

It's simply a matter of scale. The cables work on the same scale as the signals transmitted through them, hence they can have a quite large RELATIVE effect on that signal. Which then are amplified into perceptual differences.

Very simple.
post #29 of 87
It's funny to me that the same argument regarding signal amplification is also used in the context of the small differences are in essence covered. Of course those other electronics downstream of the wires also have inherent error, noise, and energy loss. Thus perhaps the argument that the differences are amplified is actually that the cable differences are "smoothed out" so to speak.

Regarding perception, I would refer anyone interested to the work of Norman Weinberger and Raju Metherate at UC Irvine, whose primary work is in this field. One of their frequent collaborators is a Scott Cruikshank, but I forgot where he's at.

I freely admit that our understanding of the human brain is rudimentary. But I also assure you that there are many people concerned with resolve the issues of perception, which is arguably more tractable at the present time than some of the questions regarding the "big picture."

There are people in neuroscience working on that as well, to varying degrees of success.

Additional resources regarding the neuro side of things includes a good chapter in Larry Squire's book by M. Christian Brown on audition and Bear, Connors and Paradiso's "Fundamental Neuroscience" text, which is particularly palatable for non-scientists.

However interesting this particular avenue of the discussion is (and to me it really deserves its own CONFERENCE!), I think the question regarding the nature of the electronics and particularly the physics of cables should remain the salient topic.
post #30 of 87
Quote:
Originally Posted by unclejr View Post
It's funny to me that the same argument regarding signal amplification is also used in the context of the small differences are in essence covered. Of course those other electronics downstream of the wires also have inherent error, noise, and energy loss. Thus perhaps the argument that the differences are amplified is actually that the cable differences are "smoothed out" so to speak....
Which is why those with the best equipment (distorts less) seem to be the ones that seem to hear the biggest difference between cables.

Kinda makes those "cable makes a difference" folks point, if you ask me.
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