High-end audio cable

High-end audio cables are a form of audio tweak intended to improve the sound quality of high-fidelity audio systems. The idea is that since the signal passes through the cable on its way from the source to the amplifier, or from the amp to speakers, an improved cable will pass the signal better than a cheap mass-market cable. Widely-held electrical-engineering theory (such as that taught at any college) tells us that basic electrical parameters such as Capacitance (C), Resistance (R) and Inductance (L) will affect the signal going through the wire. These differences that cable make can be clearly demonstrated; as they are in this Frequency Response Plot. Aside from the relatively basic LCR effects, there are a number of additional parameters that many believe also effect the sound going through cables. The theories behind these arguments are more difficult to prove, and thus lead to a great deal of debate. In any case, because "good sound" is a subjective thing, even cables that are highly inaccurate can be considered "good" by some. This also leads to a great deal of debate. Feeding the controversy are the extravagant prices for some audio cables, ranging upwards of $30,000 for some extreme designs.

Cable theory

There are almost as many theories as to how an audio cable improves the sound as there are manufacturers. Quite possibly the most universal one is "marketing", though that is a rather cynical approach given the subtleties of the human ear. In his 2001 master’s thesis, “A New Methodology for Audio Frequency Power Amplifier Testing Based on Psychoacoustic Data that Better Correlates with Sound Quality”, Daniel Cheever points out a number of flaws in conventional testing that indicate the ear is extremely sensitive to tiny signals well above the normally-expected range of human hearing. The high-order harmonics to which he refers exert an influence on our perception of the sound that is vastly disproportionate to their strength, to the point that research from as far back as 1937 indicates that high-order harmonics may actually exceed the subjective effect of their lower-order cousins. Since higher-order harmonics can be of much higher frequency and much lower amplitude than normal audio measurements measure, they provide one explanation for the apparent insufficiency of conventional electrical engineering theory in explaining the influence of high-end audio cables. Since this is but one theory, though, it is important that the reader familiarize himself or herself with the basics of audio measurement.

Common theories of cable design

Some manufacturers of low- to medium-end cables as well as do-it-yourself cable designers stick to the basics of capacitance, resistance, and inductance. (Hereafter referred to as a group by LCR, where L is the symbol for inductance and C for capacitance and R for resistance.) They are also noted for their critical approach to selecting materials based on dielectric properties (for insulators) and resistive properties (for conductors) and all electrical properties for geometry.

LCR theory dictates that low-level signal cables such as line-level interconnects be designed to minimize their capacitance and inductance.

The conductors are generally at least made from high-purity copper or even silver. (Some see silver as having a "bright," "harsh" sound with "glare," though this may simply be the synesthetic effect due to the color of the metal. Many silver-based cables have been subjectively reviewed as sounding completely unlike this common characterization.) Often, manufacturers will use oxygen-free, "long-crystal," or high-purity copper, though the particular benefits of these traits in an electrical sense are unproven with regards to audio transmission.

These cable designs are often easy to make at home, with popular "recipes" for budget high-end audio cables published by Jon Risch.

Higher-end cables are often characterized by expensive and exotic materials, as well as exotic geometries. They are usually manufactured for the vendor, whereas many lower-end cables are handmade from raw stock or incorporate ready-made cable types from vendors such as Belden or Canare.

Missing from most of these is the fact that the shield should be connected ONLY at the source end to prevent circulating currents in the shields! This fact is well established in circuits involving critical measurements.

Controversy

There have been numerous studies [1] [2] that indicate that even among audiophiles, in a double blind test it is difficult or impossible to distinguish extremely expensive, exotic speaker cables from ordinary lamp cords or budget 12awg copper speaker wire. This is a source of considerable agitation for people on both sides of the issue.

Given that the length of the signal conducting cables between the audio equipment, say from turntable | CD/DVD player to preamp, is short, the cable electrical properties are not so critical as is the geometry, and having a good metal chassis grounding and solid support. And, keeping these signal cables away from power cables to avoid mutual inductance which can not be prevented by common cable shielding.