It is the opinion of many informed individuals that there are scientific reasons that cables sound different, but
there are some that claim that the only factors that can possibly make a difference are the basic lumped
electrical parameters of the cable (the inductance, capacitance, and resistance or LCR), and the interaction of
these parameters with the audio circuits they link.

On the surface, this seems eminently reasonable, and is the chain of logic most often used by those who are
not familiar with the ins and outs of audio physics. As with many things, the reduction of an argument to a
simpler and simpler form often becomes a reduction to the absurd.

What is the more complex view? For a first approximation, break down those ultra simple and pure LCR
parameters into their actual components, and examine their deviation from the ideal behavior in the real world.

Lets look at inductance first. The simple aspect of too much inductance in a speaker cable can actually cause
a direct and inarguable high frequency roll-off, which is more severe into low impedance loads, and with longer
cable runs. This point has been argued, and I find it interesting that although many of the ABX pundits want to
insist on component matching to 0.1 dB or better, they often dismiss frequency response deviations greater
than that when it concerns the inductive effects of speaker cable. This may have something to do with the
entrenched notion that ordinary zip cord, otherwise known as lamp cord is perfectly adequate as speaker cable
despite not having been designed for such use, or despite utilizing less than the best audio grade materials in
it's construction. Obviously, it would be a true gaff to admit that the "good enough" zip cord had problems due
to a fundamental electrical parameter.

The very simple examination of inductance for speaker cables leads to the choice of cable geometry's, the
reason that some speaker cables use exotic and highly involved shapes and windings. The braided, woven, flat
strips, and the various incarnations of Litz wire are all attempts to minimize the inductance parameter.
These more than simple zip cord or coax geometry's cost more to make, require more steps in manufacture
and a commitment to more quality control and quality assurance measures.

What other aspects of inductance are there? Fundamental electrical parameters seldom exist in their pure forms the real world, none are perfectly pure or isolated from the effects of physical imperfection and less than ideal implementation.
For inductance, it is primarily the presence of materials that can interfere with the magnetic fields associated
with inductance, or that can distort the value of the inductance with frequency, level or time. These materials are
typically going to be ferro-magnetic materials, none of which is perfectly linear, and all of which will add some
amount of non-linearity to an inductance value.

This aspect of inductance may seem to be trivial and a moot point, but there are cable nay-sayers that insist
that steel core cables used as interconnects are just fine, and that the presence of steel or iron objects next to a
speaker cable will not have any effect whatsoever on the cable. So there are cases where this issue can crop
up. If we take the magnetic portion of the electromagnetic wave that is the audio signal to be associated with
the inductance of a cable, then such things as foil shields in-between the center wire and the outer braid of a
coaxial type of cable, steel in RCA jacks or speaker termination's, nickel platings (nickel is ferro-magnetic), the
proximity of steel rack legs and component chassis, or even any conductive materials, will involve the distortion
or disruption of the inductance of a cable. These kinds of factors can cause the cables inductance to vary with
level and/or frequency.

In my opinion, backed up by both listening tests, and measurements, steel in an interconnect can be heard as a
detriment, and steel near speaker cables, or in the connectors for either, can be a detriment. Excessive
inductance in a speaker cable, such as simple zip cord, can also make the sound dull and lifeless.

What about the capacitance? This is not a pure parameter either, in fact, it may be the most impure of the three
basic electrical cable parameters. For interconnects, capacitance is more of a direct threat to cable
performance than the other two parameters. A high enough capacitance coupled with a high source
impedance, such as a tube based component, can begin to roll off the high end

While not as strong of an effect as the inductive roll-offs in speaker cables, it is still a factor none the less.
Since capacitance is such a big factor for cables, it's deviations from perfect behavior are more of an
influence. What aspects are there for capacitance in a cable? There are several deviations from ideal
behavior.

The foremost in terms of audio is probably Dielectric Absorption. (See
http://www.capacitors.com/pickcap/pickcap.htm for more information)
DA is a energy storage effect, which can prevent the full impact of transients, and can blur and garble complex signals. It could be thought of as a form of distorted echo to the audio signal. There are also leakage (insulation resistance, dissipation factor, polar dielectric activity, frequency dependent capacitance, level dependence, etc. All these aspects affect the signal via changes to the capacitance of the cable, or, as in the case of DA, by direct energy delayed signal storage and release.

Once again, I have found the quality of the insulation, that which forms the capacitor in a cable, to have an effect
on the sound. Better quality dielectrics intrude less on the music, allowing better clarity and a more cohesive
and dynamic presentation.

Finally, the parameter of resistance, which is probably the most misunderstood of the three. Signal conduction
is not water through a pipe, I wish that that particular description could have been banned before it was burned
into the brains of American students! It conjures up images of the electrons, flowing like a fluid, through the
center of a vessel (the pipes), and unfortunately for the reality of it, nothing could be further from the truth.

How does the signal actually travel? An audio signal is an electromagnetic field, traveling along a conductive
circuit more like a train on a track than water in a pipe. Wait a minute, isn't the signal inside the wires, isn't it
current, and voltage? Well, yes and no. It could be argued equally well that the signal actually IS the EM field,
and that the current flow is merely a side effect. The speed of the individual electrons is incredibly slow
compared to the EM field, which travels close to the speed of light, so it is the EM field that actually carries the
signal information.

Doesn't this make the conductor even less important, if the signal is not actually IN the wire, then why would the
wire itself have any effect on the signal? This is because, just like the other parameters, resistance has an ideal
that is seldom approached, and the deviations cause the side issues to have their affect. For resistance, we do
have a unique situation, we have a paragon, an realizable ideal of zero resistance in the effect called
superconductivity. A superconductor would behave in such a manner that virtually no current would flow inside of it, virtually no voltages would be detectable inside of it, as it's perfectly conducting nature would prevent the EM field from penetrating beyond the immediate surface, just deep enough to invoke the super conducting paradigm, and once the superconduction occurred, no further penetration would be possible.

Note that for a true superconductor, the surface of the wire would be of paramount importance for high
performance audio use, as it is where almost ALL the current flow would be, and where all of the AC audio
signal would traverse.
For the EM field that is the actual signal, is influenced and affected by the current flow on the surface (or within)
of the wire, if an irregularity were to cause the current flow to be interrupted, the EM field would be
correspondingly distorted. What this would mean in signal terms is that the local EM field would be disturbed,
probably squeezed together as the disruption in the current flow on the surface of the wire was encountered.
This lopsided pinching of the EM field might sound like a ever so minute moment of compression, a bobble or
burp in the even and regular flow of the signal. Now one microscopic imperfection in the conductor would not
be readily detectable by the most sensitive instrumentation, and I would agree is totally inaudible BY ITSELF,
but if the audio signal encounters literally thousands or hundreds of thousands of these minute imperfections in
the current flow along the wire, perhaps literally millions in the entire length of the cable, then the significance
may be much greater than you might think.

The absolute level of these individual events may be on the order of -150 dB, or even lower. Lets just use this
figure for purposes of discussion. So how much of an effect would many of these happening through the length
of the cable have? Since the transit time through the cable is so short, the irregularities would all essentially
occur at the same time as far as our ears were concerned. Now, how do you add up all these minute signal
imperfections? Randomly related "signals" are added up as a power function, that is, doubling up will add to a
3 dB higher level, 10 times as many is a 10 dB increase. What about a million? Well, that would be an increase
in the effective level of the irregularities of about 60 dB. Wow! All of a sudden these insignificant little
conductive imperfections have become that much bigger in total effect. Now instead of being down below any
reasonable level that anyone could argue about, they are now at -90 dB. This is within the realm of possible
audibility, especially if they were slightly more intrusive than one might assume. Could they be the "grain" that is
sometimes heard, the lack of ultimate clarity that all common conductors have? Could different metals and
materials have different levels of irregularities, and hence a different amount of, or freedom from grain?

Several cable companies claim to have developed proprietary alloys for their cable conductors, ones that minimize, or even eliminate the typical crystalline structure defects that plague commercial copper. Most commercial copper has irregularities of hundreds of discrete crystals or more per inch of wire. This is just a raw count of what we know of as copper crystals, this does not necessarily reflect the actual amount of potential current flow irregularities.

Purity of the conductor would affect how many of these irregularities in the current flow there might be, as well
as the nature of the impurities, as well as the processing of the conductors, annealing, cryogenic treatment, or
other proprietary processes or treatments. See my post down below in the copper purity thread re common
copper purity levels.

Besides these factors, there are the usual resistance issues of temperature coefficient, voltage coefficient,
rectification and other resistive deviations from linearity that affect conductors and connections, soldered or
otherwise.

Now the expansion of the basic three electrical parameters to their more actual behavior is already enough to
shed some light on the situation with esoteric and expensive cable designs, but this is not the whole story.

There is vibration of the cables to consider, we almost always assume that the cables are as a rock of the
universe, without external stimulus, such as the vibrations from the speakers. Even if there were no sound
vibrations to impinge on the cables, the cables themselves would provide a mechanical stimulus, as the very
act of carrying current will "twang" the wires with a physical shock, and any motion that results will then be
translated into a new signal, one which is related to the physical resonance of the wire and insulation system,
and no longer related directly to original stimulating signal.

There are further effects, related to voltage electrical fields, interactions with shields and balanced electrical
conduction vs. unbalanced (even within the case of an unbalanced line level feed).

Are there scientific reasons for expensive cables? Yep, sure are.

Jon Risch

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