The Truth Behind Instrument Cables

author: Kevy Absolution date: 08/06/2009 category: the guide to
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The Truth Behind Instrument Cables
Every instrumentalist is faced with a variety of supplies to buy, and of course advertising plays a large role in consumer mentalities. In the world of instrument cables, this is no exception.

Many brands produce cables ranging from the lower $20 ranges up to $200 a cable. Why is it, though, that many brands charge so much more for their cables? Can they really make or break your tone? The best weapon that a consumer can walk into a store with is knowledge. While this article is not going to convey one cable as bad and another as good, it will offer an unbiased explanation of cables, why they are priced as such, and will help you to make better purchasing decisions.

I believe it's important to note than instrument cables are, for the most part, analog cables. There are numerous discussions about unfairness in advertising among specific brands regarding digital cables; because these forms of signal are carried differently, the arguments and counter-arguments against said brands are not going to be accounted for in this article.

So what's in a guitar cable? This is the face that quite often shocks consumers who swear that one brand of cable provides better sound quality than another. Quite simply, a guitar cable is a shielded piece of copper wire, with a core diameter of .265". All standard 1/4" instrument cables are this thickness, and therefore have the same resistance and signal impedance.

I'll throw the big shocker in right now. What does this mean? Any two cables made of the same copper components and of the same length will deliver the same signal quality in the end. So yes, the $100 Monster "Rock" Cable, and the $20 LiveWire cable of equal lengths are essentially equal.

The proof is in the laws of resistance: the equation (R=p*l/A) states that resistance (in Ohms) is proportional to the length and resistivity of the wire, and inversely proportional to the cross-sectional area of the wire. In layman's terms, that means that a short, thick wire provides the best signal quality. And because the cross sectional area is the same, the resistivity of copper doesn't change (16.78 Ωm), and the length of the wire is determined by the consumer, we come to the astounding conclusion that all these cables do in fact provide the same tone quality.

So we now know that the claim of an expensive cable being "better" cannot be attributed to signal quality. So what can they offer? While the signal quality is the same, what other aspects can be improved upon? Here's a list of other cable aspects to look for which are often advertised:
  • Shielding: To keep interference from reaching the "hot" center conductor where the signal is passing, the copper "shield" covers the conductive core. The shield is usually formed of braided copper, and a low transfer impedance to the ground is the sought-after quality.
  • Insulation: The copper conductor must be insulated to preserve signal quality, and of course to protect the user. Most insulation is made from thermoset (rubber and neoprene) or thermoplastic (polyethylene and polypropylene) materials spread over the conductor, then vulcanized. Insulation doesn't affect signal quality and is usually standardized across cables. The thickness does, however, determine cable flexibility.
  • Protection against 60-cycle hum: Many cables, especially higher-priced ones, advertise a strong protection against electrical hum. The sad truth though is that this hum (sourced from 60 and 120Hz frequencies from power sources) are usually low enough in frequency to be stopped by anything but a ferrous metal component. The best defense against hum is to keep coiled-up excess cable stored away from power sources such as amplifiers and power splitters.
  • Connecting Ends: We've all seen the attractive gold-plated connectors on some big-name brands. And of course, if it's gold, it's better... right? While many people believe that gold-plated connectors are "better", they don't know why. Gold is an attractive anti-corrosion element, but signal-wise, there is no benefit of having one connector over the other at the frequency range for instruments.
So if there isn't a huge difference between the upper and lower priced cables, why is there such a gap? Why do some brands charge almost twice as much as the lower end cables, when they can't offer much more? The answer is mark-up. Consumer reports have shown that many top-of-the-line cable manufacturers sell products at retailers for up to 200% price increase. It's important for consumers to consider all brands of cables before buying, because while the higher-priced brands to offer nice little bonuses, in the end, they usually aren't worth the money to the everyday person.

So go forth and buy new cables, but arm yourself with knowledge and be aware of your own needs and what different cables offer you. In the end, you can save yourself a lot of money with a little thought.

Works Cited

Pro Co Sound. "Understanding Instrument Cables." Pro Co Sound. Web. 5 Aug. 2009. "Resources: Standards & Properties - Properties of Wrought and Cast Copper Alloys Search." Web. 05 Aug. 2009.

A big word of thanks to my father, who's experience in electrical science has helped me to not only better understand how I play, but to also appreciate it. Without him, large amounts of my articles would be missing, and my struggle to discover truths wouldn't be half as large.

By Kevin Heiland.
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