The Signal Construction & Speed Parameters in Audio Cables
When we design a hifi, video or digital audio cable we always consider three main elements:
- The conductor material and its construction;
- The insulation or dielectric material
- The overall design of the cable - whether it is an asymmetrical, also called co-axial, or a twisted pair cable, etc. - is not a problem.
The conductor material that we prefer to use is made up of a single section, made of extremely pure copper or silver, of the monocrystalline type (Ohno Continuous Cast) that does not create discontinuity in the signal path.
Depending on the use, the conductor can be a single wire or a weave of wires of the same diameter or different diameters.
The theory says that an excellent cable is simply made up of two wires of pure conductors free in air, although practice teaches that it is necessary to cover the wires with an insulating material, normally plastic, in order to prevent the two wires from short-circuiting and to protect the conductors from corrosion, both copper and silver being particularly sensitive from this point of view.
Now, instead of having two free cables in the air, we use two insulation casings that form a dielectric. In doing so, the cable has now become a capacitor, or a distributed capacitor.
If the cable is a coaxial (asymmetrical) signal cable then the capacitance is between the inner conductor and the shield (or sock) and because its inductance is very small the cable acts as a series of small low-pass networks, which attenuate the higher frequencies (deepen the low-pass networks on Wikipedia).
As a general rule, the higher the capacity, the longer it takes for the signal to pass through the cable, and therefore the slower the audio cable.
What do we mean by cable speed?
Well, the most commonly used term is VOP (Velocity Of Propagation), which refers to the speed at which the signal passes through the conductor.
You can see, in the data sheets of our cables, the VOP values for each specific cable.
VOP is defined as the speed of light in vacuum (C=299,792,458 meters per second). We can say that light travels about three meters in ten nano seconds, so if we measure how long it takes for an impulse to travel a wire we can define the speed or VOP as a fraction of the time that the light would have taken if it had a value of 1.00.
This measurement is obtained through a technique called TDR (Time Domain Reflectometry). The TDR technique is based on the fact that by injecting an impulse into a cable without termination, the impulse will be reflected back from the open termination and will return to the starting point.
This test called Time Domain Reflectometry shows us the VOP (read more about the TDR here).
All dielectrics slow down the signal speed, the best ones slow it down in smaller amounts.
A faster signal results in fewer deletions, so a faster cable provides more information.
As it's easy to understand, VOP is a very important datum, we don't know that other manufacturers provide VOP data, so it's difficult to make comparisons, but the latest Atlas audio cables using Microporous Teflon, or Teflon, or expanded polyethylene dielectrics are very fast, have fewer cancellations and therefore transmit more information.
At Atlas our mission is to improve your listening pleasure. We don't put barriers in the signal path, nor do we divert the signal using material conductors of different characteristics, but we make low cancellation cables that transmit more information.