All cables are the same ???

Minimal tonal change... 

Cables should be judged by their neutrality and not tonal manipulation

It is quite amazing just how many high priced and incorrectly executed cables are offered in the market.

Inasmuch as describing how audio signal distortions in cables are created entails understanding many complicated physical laws, there are easy mechanisms to follow to determine why their sound is different. By understanding the following and trial test auditions, one can learn whether a cable design is executed properly or not.

You can determine whether it is worthwhile spending time with a particular product or not. Keep an open mind but also a good portion of skepticism too!

A wonder is, “at the time it happens a yet explained reality.”
The earth is not flat, thunder and lightening are not products of all-powerful super-beings, mankind did not derive from Adam and Eve, natural medicine is not occult, radioactive material is dangerous and electro-acoustics is physics…
J.E.

A cable’s skin effect is one of the greatest hurdles in designing a good audio cable. This term is often misused but it does define an actual phenomenon.

It appears often thought that the skin effect lowers the conductance and the –3dB point (one half of amplitude) for a cable typically lies by 50 kHz, that there is no influence upon the audible (20 – 20,000 Hz) signal.

In actuality, long before the skin effect loses amplitude, changes in resistance and induction take place. These changes cause different frequencies to react differently, more or less depending upon their distance to the exterior of the conductor.
When a single conductor is too thickly gauged, too thick, then the skin effect causes different spectral portions of the audible signal to act differently. Each portion of the audio signal will react differently and their flow of electricity meets (‘sees’) different cable parameters.

What this boils down to: especially critical high-frequency information ‘sounds’ smeared. The ear misses the sonic cues and details, openness, and rejects the performance as dull sounding and ‘hears’ a flat sound stage. The signal energy is the same, of course, but the information is garbled so that one suspects the mid-range lost its over-tones.

There is a standard formula, 1/e (= 63%), with which current loss versus gauge / diameter of a copper wire is calculated. 

The entire formula is
1/e = 0.0661 : square root of Frequency (m).
The result, for example, at 20,000 Hz of a 63% current loss at a depth of 0.467 mm is a cancellation at 0.934 mm (18 AWG).

This formula does not indicate at which frequency the skin effect becomes audible. Careful tests showed audible distortion at even less depth.
Therefore, it is not correct to determine 63% as acceptable current loss figure. 
There is a solution for problems caused by skin effect: utilizing a conductor of small yet large enough gauge (more thin), that the skin effect towards the center of the core has little or no effect.
A gauge of 0.8 mm diameter is about the largest without inducing audible negative skin effects.
Grossly thinner gauges do not reveal better results (!) and the scope of solutions came into focus.

The GERMAN HIGHEND silver wire used in mid- to high-frequency transfer has maximum 0.75 mm diameter. 

Do not make more problems than can be solved !

Inasmuch as 0.8 mm diameter conductor is too thin for loudspeaker cable use the next project was to create a larger electric conductor without creating new problems.
If we bundle several conductors together this combined cable is seen as one and underlies the same physical attributes regarding skin effect as a single conductor, the outside parameter of the conductor allows high frequency signals to pass easily whereas the deeper within the conductor, the poorer, that is better for lower frequencies.
The down-side of the resulting phase shifts  is mentioned above.

To complicate matters, unfortunately the single conductor strands are not always precisely laid and spaced throughout the length of a woven or twisted cable. At the beginning of a cable the conductors are differently oriented as in the middle or end of the same cable. This creates a situation where the electric current has to ‘jump’ from one conductor to the other thousands of times as the higher frequencies flow on the outside. The neighboring conductors are not always perfectly symmetrically laid and the pressure of contact differs, and dissimilar oxidation compiles the filtering effect on the signal creating a hap-hazard schematic of electric current flow.
Environmental influences (especially in auto-hi-fi) contribute to an ‘aging process’ that actually causes [sonic] signal deterioration with age.

Magnetic induction is another serious problem

It is given that every conductor carrying electric current is surrounded by a magnetic field. Neighboring conductors create dynamics  which –on a molecular level- modulate themselves. The bass signals have the strongest electrical currents and modulate the exterior (high frequency) of the conductor as well. In turn, the (due to modulation) mechanical pressure changes affects these ‘jumping’ currents that are also modulated. Most good cables use a so-called Hyperlitz design that counteracts the magnetic induction to an almost negligible minimum. Meanwhile it is clear why most good cables use heavy gauge conductors instead of thin wire bundles.
The heavy gauge conductor is relatively impervious to mechanical modulation.
Magnetic induction is basically the main reason for so-called bi-wiring with separate leads to the high frequencies and the low frequencies and why this alternative benefits the audio signal. The bass signal energy does not influence by modulation the signal to the tweeter.

The cable’s conductor material also dramatically influences the sound

Considering the electrical conductance of copper and silver, both are excellent conductive materials, whereas silver is better than copper but unfortunately costs much more.
Silver plated copper works well in video and digital applications, however in audio signal transfer we still have the above-mentioned signal-distorting problems.
The less expensive copper material is available in various grades. When one refers to ‘pure’ copper, then this quality is where there are circa 4,500 copper crystals per meter.
The electric current must pass beyond the boundaries of these crystals and while flowing create the same ‘jumping’ distortion as encountered with bundled wire conductors. The first step in better conducting quality copper is “oxygen-free high-conductive” (OFHC) type copper. It is made by special drawing process which reduces the oxygen content from approximately 235 ppm (regular copper) to roughly 40 ppm (OFHC). The lower oxygen content drastically reduces the oxidation between the copper crystals and thereby lowers distortion. It reduces the amount of copper crystals by 75%, thus contributing to lower distortion. The sound conveyed by a OFHC cable is smoother, cleaner and more dynamic than cables of the same design using regular high purity copper.
The next higher grade copper cable is long-grain copper (LGC). Drawn with extreme care, there are maximal 200 crystals per meter. Predictably, cables of the same design made of LGC instead of OFHC sound even better.
Flexible printed circuit (FPC) copper manufactured in a comprehensive sinter process creates a single crystal of circa 200 meters length (the crystal length in a MC pick up cartridge is up to 1,500 meters). The sonic benefits are easy to hear. 
Is FPC the best copper material? Recently a new product, FPC-6, became available and has roughly 1% of the impurities of FPC.
The impurities in purest (99.997%) copper are silver, iron and sulfur with traces of antimony, aluminum and arsenic.
FPC-6 has a purity of 99.99997% copper with roughly 19 ppm oxygen, 0.25 ppm silver and less than 0.05 ppm other impurities. This quality of copper sounds sensationally good and only the human hearing is instrument enough to discern the effectiveness of such chemical expertise.
When copper reaches such extreme purity the only sonic improvement possible is reverting to high-purity long-crystal silver.

Unquestionably is FPS silver the cable material of choice

Unfortunately FPS silver as raw material is very expensive but properly implemented, the transparency, colors and neutrality are beyond comparison.

The importance of loudspeaker cable design

We have looked at the inherent problems of individual conductors. The arrangement of many conductors is also important. When the neighbouring conductors, seen mechanically, do not conduct evenly, then this too is detrimental to the signal.
The arrangement of conductors can be parallel or twisted and either has its benefits. Parallel arrangement is good but expensive. Twisted offer very good IF shielding as well as inductive versus capacitive relationship.
A cable can have one or more conductors. The arrangement of these conductors sets the magnetic relationship to another in cable capacitance and inductance.

Some believe that capacitance and induction are the most important factors in designing audio cables. Of course this is not the final word. 

Nevertheless is the filter characteristics composed from the passive values responsible not only for the frequency response but also and more importantly for the phase integrity. Although induction and capacitance are not the ‘last word’ in cable design, they are respected and their values kept as small as possible.
There is a cable design theory that promotes the idea that the cable’s impedance should match that of the loudspeaker.
This can not be accomplished!
Although this theory is viable, as one learns in digesting the painful work “The Conductive Theory” as engineering student, the proper matching of impedance(s) –passive and active resistors- is essential.
Amplifiers have no output resistors matching those of the loudspeaker (actually, amplifier designers try to accomplish the opposite), and each loudspeaker has its particular impedance that changes as the frequency varies.

INTERCONNECT CABLE DESIGN (cinch, XLR, etc.)

If you have not read the first part of this study, then please do now. Many identical problems exist in both low and high current applications. There are differences in setting priorities for these problems.

Low current conducting cables also suffer from skin effect, electrical and magnetic induction and raw materials.The effect from mechanical modulation is, related to the low amount of current passing, relatively little.
The lower the current, the lower the magnetic field and induction.

The insulation, dielectric, is of much greater impact

The dielectric behavior determines  how poorly or well electric energy is absorbed or travels and this has a large impact upon the sound of the music.
The technical term, "dielectric constant" refers inadequately to the effect upon the music signal. Considerations for speed propagation or absorption behavior are more helpful. The problem with different dielectrics is predominately that the insulation closest to the conductor acts like a capacitor (absorbs and releases energy). The insulator stores energy only to dispel it again shortly thereafter. The best isolator, therefore, is a vacuum. If however a stiff material needs to be used as an insulator, then it should appear ‘invisible.’  The less energy it absorbs, the better. The energy that is absorbed should stay absorbed (that is, turned into heat), and the energy that is reflected should reflect without phase changes, and this throughout the entire frequency spectrum. 
The typical insulators are PVC, PE, PP –plastics and Teflon. They can be combined with air (foam) or designed to incorporate as much air as practical. The material as well as incorporation determine dramatically the efficiency of a cable. PVC is the simplest insulation material as it absorbs the most. PE is the most-used material and it absorbs less energy and creates fewer distortions. PP is electrically ‘harder’ and has an ever better acoustical performance. Teflon is the best obtainable standard material.

The cable capacitance is more important to interconnect (NF-) cables than for loudspeaker cable

There are two reasons. If a long highly capacitive cable is used on a preamplifier, then many preamplifiers can not provide enough electricity for the cable. The resulting distortions are not created by the cable but rather in using it. The other reason it is better to incorporate a low-capacitive cable is that a high capacitance creates a strong electric field between plus and minus conductors which means more energy is dissipated into the dielectric material.

Important facts about cables

Fact:
As with all audio components, cables need time to “break in.” Cables require about two weeks use before showing their merits and about the same amount again for the dielectric to stabilize electrically, as well as with the components.

Fact:
All cables are directional, and should be used in that direction. This is so with the simplest copper cables from your local builder’s supplies store to silver conductors. Normally cables are marked so to determine the proper direction for the flow of current (the printing on the dielectric may, and typically does, indicate the drection - as you read: from the source to the receiver). If the cable is not marked you have to rely on ‘hearing’ the proper direction. In one or the other direction the sound carried will clearly be more relaxed-sounding, easy to listen to and believable. Why this is so is not entirely understood. A partial reason is that when a wire is drawn, the crystalline structure is not symmetrical and as such has its ‘own’ (preferred) directional electric energy flow.

Fact:
Many high quality loudspeakers can be „bi-wired.“ Such loudspeakers have separate inputs for the bass and another for the mids and highs.
Bi-wiring is useful to reduce the distortions caused by the cable in the bass registers. In bi-wire mode, the one cable for the highs is not effected by the magnetic field caused by the bass signal. It is a good idea to utilize the bi-wiring opportunity if the loudspeaker-designer intended this. 

By the way:

If you use the gold-plated bridges on your loudspeaker input as intended, then you are likely to have poorer sound than were only one input!Take advantage of bi-wiring if available.You do not usually permanently use the cheap interconnect cables included in the packing of higher quality components.The investment in expensive bi-wiring adapters is certainly better than the gold-plated bridges but compared to properly executed bi-wiring cables, more like a physical mistake and monetary rip-off.Stereo RCA interconnects have problems due to spatial distancing of the ground wires that is not the case with 5-pole DIN  cables with one common ground and common shielding. If the interconnect cables are lying apart, then the separate grounds create a loop in which foreign alternating magnetic fields create, e.g., hum or high frequency distortion.This is the reason why some manufacturers still use the good old DIN plugs.This is not a satisfactory solution as the contact surface of these plugs is not overly large and the manufacturer of high quality cables is next to impossible, at least impractical. A help is lightly twisting the wires whereas whether left or right each has its own sonic imprint as each channel has different matching (possible negative side-effect in Stereo version).

A conductor functions rarely alone...

In order that current flows, the electric circuit must be closed . For practical purposes, cables have two conductors that run parallel or coaxial. Special cables have multiple conductors and for the position of each of these conductors, are certain rules [of behavior]. On the one hand, are the magnetic fields about and between the electric conductors and on the other hand the electric fields decisive for the cable design. As a rule of thumb, different connections of the same conductors react  differently. With specific diameters, quantity, connections one gets different losses. 
The objective is to set the conductors so that there is the least typical loss.
A classic example is the “Schraenkstab” (no English word, sorry), two bundles constructed of many conductors wound around a common axis.

Cables are made of metals such as copper, silver, aluminum, gold, or metal-free carbon (manufacturer van den Hul), either in high purity or mixed or conductor with complimentary plating.
Oxides, cracks, dents, non-homogenous areas in materials are a hindrance for the electron movement and undesirable.
The longer the length, the more eddy current loss.

Cables vibrate and modulate.

Cables are afflicted by airborne waves from the loudspeakers and effected by microphony (vibrations).
When pressed together, the capacitance increases because the conductors are closer together while the amperage falls but voltage stays the same (U=Q/C). With increasing length so increases the problems with microphony, as more mass is moving, more energy is absorbed and released more slowly, is slowed down. Also the [soft] insulating material changes its density under pressure as well as its derivative and its dielectric properties. Under the influence of the loudspeaker sound waves a manifold assault on the cable’s parameter is made. 

Cables make electricity

Cables have a piezio-electric characteristic that creates its own current from the impurities in the insulating materials and water – moisture seeps in.This is the main reason why manufacturers seal the ends of a cable on the spool or cable makers typically seal cable endings, plugs, with heat-shrink after soldiering.The longer the length, the higher risk for the piezio-effect.

Cables magnetize (load – static electricity) themselves

The insulation loads itself against other surfaces, e.g., carpet. This static electric effect influences the sound transferring quality of cables.The longer the length, the greater the effect. The further conductors are apart, the more tendency to produce an ‘airy’ sound signal.

Cables are antennas 

They received electromagnetic fields. One avoids this with a shield and this can be in various forms, each having a strong effect upon the result. To counteract electromagnetic fields, cables can be twisted, or surrounded by foil or wire mesh.  A solid copper shield can also protect against electromagnetic influences if it is thick enough (min. 1mm). How the amplifier reacts, ‘sees’  the remainder of the high-frequency information is another issue altogether…Shields also have negative sonic impact...

Cables are directional

This is due to manufacturing influences on the crystalline structure and the placement of the strands . Even in apparent symmetrical design one must consider that the plus pole reacts differently to influences from neighboring materials than the minus pole (and ‘earthed’ partners). Symmetrical ‘behavior’ is typically unrealistic as the current drawl to the components composes different problems (e.g., loudspeaker cables). In recent times there is an increasing common opinion that also ‘burning-in’ influences the cable’s directional preference. Robert Harley’s research about „jitter“ in CD players and cables show strong differences in directional capabilities of digital cables by the “jitter” values noted. Differences in high frequency static (distortion) have been demonstrated by the Swedish cable manufacturer Supra. The directional influence upon high frequencies is also apparent with the shielding and is likely an explanation as to differences in audible performance in audio playback.

Shielding

Shielding can work differently depending upon its directionality, whether it carries primary current or erroneous current, connected only on one side, be it with the signal or the distortion that dissipates (vocabulary: coupling) in the cable. Tube or wound shielding from copper or aluminum with 100% coverage, or weaves of conductive plastic or combinations of wound aluminum with woven copper sleeve, there are surprisingly numerous variations with as many acoustically ‘different’ results. The shield is seriously  responsible not only for mechanical but also conductive and sonic properties of a cable. Where the shield is laid on quasi-symmetrical cables has to do with the materials and construction. Coaxial cables dictate that the signal return  and the ground ‘is’ the shield. In multi conductor cables a [separate] designated conductor the signal return and earth and the shield is separately connected either at the source or at the contact with the next component. For shielding is the quality of the shield important:
Surface shielded (max. 100%), wall thickness, electrical parameters of the materials, to crystal structure, to ensure that even the most minute electromagnetic waves do not influence the signal conductors.
As shielding can also have a negative influence (induction, capacitance, etc.), some manufacturers do without them altogether (e.g., Eichmann)..

Typically

- silver-plated cables ‘sound’ overly bright and aggressive 
- silver cables ‘sound’ tonally balanced and natural
- cables of cheap material ‘sound’ not precise and slurred, … even  distorted 
- thick cables ‘sound’ precise, energetic and ‘lean’ in bass, but otherwise …not precise and slurred in middle and 
  high frequencies
- thin cables ‘sound’ precise and believable sound-staged in middle and high frequencies, …but not precise and ‘fat’
  in the bass 
- litz (multi-conductors) ‘sound’ not precise and slurred in middle and high frequencies
- solid conductor cable ‘sound’ precise and full of detail  

Of course the same physical conditions (restraints) propagate as well for connectors, circuit boards, components, etc.  (It is a real phenomena that inadequacies in cable design and construction can actually ‘hide’ faults in components, that this can ‘sound’ like an improvement).    

Here is some more information [in German] about this theme
(from: G. Hilscher, Institut für Festkörperphysik)   

Tip:

Before you invest in the cabling of your audio-system, take a look at the components in your loudspeaker’s crossover. Even some well-known firms are inappropriately frugal….
An investment in valuable silver cable does not make much sense, if for example a fifty cent capacitor is mounted in front of the tweeter….
Also, the relation to the investment in cable needs to be proportionate with the qualities of the present music playback system.

Only a spoiler does not make a race car.

The original text above, All cables are the same ???  is the combined work of:

Christian Reck  (German Highend Silberkabel)
Jörg Erwin  (A&V High End-Systems)

" High End made in Germany "

-any reproduction in part or whole without prior permission is strictly forbidden-