THE FIRST LESSON IN AUDIO CABLE DESIGN
The primary problem of audio cables was discovered and addressed
over 100 years ago, when telephone companies struggled with problems
of intelligibility over very long phone lines. British mathematician
Oliver Heaviside theorized that this problem was caused by inductive
(electromagnetic) loss, and in 1893 he proposed the solution of
increasing the inductive coupling between the two conductors to
reduce the inductive loss of the telephone circuit. This solution
was implemented in 1900 with telephone loading coils, which are
still in use today. These coils are connected at intervals along
phone lines to preserve the fidelity and strength of the signal.
The most audible differences among interconnect and speaker cables are also the result of inductive loss. While some listeners may actually like certain sonic colorations caused by cable inductance, these effects are always accompanied by dynamic compression and masking of the finer sonic details. For example, speaker cables with widely spaced conductors exhibit so much inductive loss that they distinctly thin out and compress the sound. Wireworld's DNATM cable designs are engineered for optimal inductive coupling between the two polarities, for dramatic improvements in the preservation of harmonic structure, three-dimensionality and dynamics.
EVALUATING
CABLES OBJECTIVELY
Objective listening tests clearly demonstrate the superior fidelity
of Wireworld audio cables, which also preserve square waves better
than other cables. The problem with purely analytical evaluation
by test equipment and specifications, however, is that they can
be easily misused in cable marketing and are often misleading.
Test instruments are useful, but the most important cable parameter
of all is value, which can only be measured with human perception.
Some people still doubt that there are any real benefits to upgrade cables, pointing to testing such as the ABX cable tests performed by the Audio Engineering Society, which failed to prove that any cable differences were audible. However, ABX testing also proved to be useless in the development of the compressed audio formats, such as MP3, and are therefore of questionable validity in sound quality testing. The listening tests performed by the Motion Picture Experts Group (MPEG) and Wireworld are 'ABC-hidden reference' tests, where the testing involves a 'control' such as a bypass (i.e., a direct connection) and the listener controls the switching. Wireworld has promoted double-blind cable testing for over a decade because it provides valuable answers when it is done correctly.
INSULATION
MATERIALS
The materials used to insulate the conductors in audio and video
cables can be a significant factor in their ultimate performance.
Fortunately, some inexpensive materials, such as polyethylene
and polypropylene, introduce minimal signal loss in cables. Many
audio cables and some video cables are insulated with lesser materials,
such as PVC, a lossy insulator that can degrade audio and video
fidelity. All Wireworld cables are insulated with superior materials,
which enable them to preserve as much of the signal as possible
for their price.
DIRECTIONALITY
The microstructure of copper and silver conductors is actually
made up of individual grains. Unavoidable angular patterns in
this grain structure can cause cables to perform differently in
both directions. Wireworld cables are manufactured utilizing a
proprietary Grain OptimizationTM process that specifically
controls the grain structure of the metal to produce the highest
fidelity when the signal flows in the direction of the arrows
printed on the cable.
Some other brands of audio interconnects are directional because their shields are only connected at one end of the cable. The shields in Wireworld cables are connected at both ends to provide superior isolation from noise.
CONDUCTORS
Of the various impurities commonly found in copper, oxygen is
especially problematic because copper oxide can restrict conduction
within the metal. Oxygen-Free Copper (OFC) contains less oxygen
than the common ETP (Electrolytic Tough Pitch) copper, making
it a better conductor for audio and video cables. OFC is also
known as 4-nines (4N) purity because it is specified as 99.99%
oxygen-free. OCC is the trademark for Ohno Continuous Casting,
the most advanced process for refining and casting copper and
silver conductors. OCC copper and silver conductors are guaranteed
to be 99.99997% (6N) pure.
Superior conductors
can improve the performance of audio and video cables, but they
cannot correct cable design problems. For example, silver is 6%
more conductive than copper, and silver oxide is a much better
conductor than copper oxide. These advantages improve resolution,
which tends to magnify the inductive colorations of most silver
audio cables. Wireworld's silver cables are carefully engineered
to maximize the advantages of silver conductors for even cleaner
and more lifelike sound and imaging than the same designs with
copper conductors.