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A Technical Introduction to Audio Cables

Written by Adam Blake

A Technical Introduction to Audio Cables

What is so important about cables anyway?

One ofrepparttar most common questions asked by consumers faced with purchasing cables for their audio or home theater system is, "What is so important about cables anyway?" They can cost as much or more than some ofrepparttar 138186 hardware inrepparttar 138187 system and to many it is difficult to understand why wire isn't just wire.

To begin to understand how audio cables work, we have to start withrepparttar 138188 two fundamentally different types of audio cables you are likely to have in your system. The first type of cable is called an interconnect, which is used to connect various components together (such as a CD player to a receiver). The second type of cable is calledrepparttar 138189 loudspeaker cable (this isrepparttar 138190 wire going fromrepparttar 138191 receiver or amplifier torepparttar 138192 speakers). It is important to realize that both types of cables are carryingrepparttar 138193 same information, just with different amounts of energy.

Interconnects carry a signal with very little energy. These cables only need just enough energy to conveyrepparttar 138194 information fromrepparttar 138195 source, for example a CD player, torepparttar 138196 amplifier. The low energy requirement means thatrepparttar 138197 signal in interconnects has very little current (usually inrepparttar 138198 range of thousandths of an amp).

Loudspeaker cables onrepparttar 138199 other hand, carry a large amount of energy. All ofrepparttar 138200 energy required to moverepparttar 138201 speaker cones and make sound must come throughrepparttar 138202 loudspeaker cables. Because ofrepparttar 138203 high-energy requirement in these cablesrepparttar 138204 current is relatively high (currents can reach 10 amps or more).

The very basic reason why audio cables are important is because they changerepparttar 138205 signal going through them. There are two different, fundamental ways that an audio cable can changerepparttar 138206 signal. The cable itself can changerepparttar 138207 signal, orrepparttar 138208 cable can allow outside sources of energy to change repparttar 138209 signal.

In order to understand how these two situations can occur, some basic background electrical knowledge is needed.

Signals in all types of wires are conveyed byrepparttar 138210 combination of voltage and current. Every signal has some amount of voltage and some amount of current. The largerrepparttar 138211 difference in voltage between two places, sayrepparttar 138212 beginning andrepparttar 138213 end of a cable,repparttar 138214 largerrepparttar 138215 amount of current, and vice-versa. The direct analogy to voltage and current is repparttar 138216 flow of water through a hose. The amount of water flowing throughrepparttar 138217 hose is analogous to current. The water pressure inrepparttar 138218 hose is analogous to voltage. The higherrepparttar 138219 amount of water pressure,repparttar 138220 more water will flow through repparttar 138221 hose. The higherrepparttar 138222 amount of voltage,repparttar 138223 more current will flow throughrepparttar 138224 wire.

Every cable has a set of electrical properties that can be measured using standard electrical testing equipment. The three most basic properties are resistance, capacitance and inductance. While a detailed description of these three different electrical properties is outsiderepparttar 138225 scope of this article, a basic description ofrepparttar 138226 relevant effects of these three properties can be given.

- Resistance opposes current. The higherrepparttar 138227 resistancerepparttar 138228 greaterrepparttar 138229 amount of energy that is removed fromrepparttar 138230 current and turned into heat.

- Capacitance opposes changes in voltage. If a voltage is increasing, capacitance will causerepparttar 138231 voltage to increase more slowly. If a voltage is decreasing, capacitance will causerepparttar 138232 voltage to decrease more slowly.

- Inductance opposes changes in current. If current is increasing, inductance will causerepparttar 138233 current to increase more slowly. If current is decreasing, inductance will causerepparttar 138234 current to decrease more slowly.

The final piece of background knowledge that is needed for this article is whatrepparttar 138235 audio signal looks like. If one were to takerepparttar 138236 speaker cover off a speaker to look atrepparttar 138237 speaker cone while music is playing, you would see that it is moving back and forth. In order to moverepparttar 138238 speaker cone back and forth,repparttar 138239 electrical signal must push and then pullrepparttar 138240 cone in rapid and repeating fashion. This is accomplished by having an Alternating Current, or AC. Alternating Current simply means thatrepparttar 138241 voltage oscillates between positive and negative. Becauserepparttar 138242 voltage drives repparttar 138243 current, this means thatrepparttar 138244 current also goes positive and negative. In other words,repparttar 138245 current is going back and forth inrepparttar 138246 wire, just likerepparttar 138247 speaker cone. The subtle variations in how fastrepparttar 138248 voltage and current go back and forth createsrepparttar 138249 different sounds that we hear when listening to music.

How a cable itself affectsrepparttar 138250 audio signal

Now, going back torepparttar 138251 ways thatrepparttar 138252 cable itself can change repparttar 138253 signal going through it, let's consider both types of cables separately.

As stated previously, interconnect cables carry a very small amount of current. Relative torepparttar 138254 currentrepparttar 138255 voltage is large. Because of that fact, capacitance is important, but inductance is relatively unimportant. Asrepparttar 138256 voltage oscillates between being positive and negative,repparttar 138257 capacitance slowsrepparttar 138258 voltage changes down, and causes delays. This can cause audible distortion inrepparttar 138259 sound. Because interconnects have very little current, resistance is not much of a factor. Even an interconnect with extremely high resistance will only remove an infinitesimally small amount of energy.

The signal in loudspeaker cables is essentiallyrepparttar 138260 opposite ofrepparttar 138261 signal in interconnects. Both cables haverepparttar 138262 same information, but in loudspeaker cables,repparttar 138263 voltage is small andrepparttar 138264 current is large, relatively speaking. Because of repparttar 138265 high current, both resistance and inductance are important in loudspeaker cables. The higherrepparttar 138266 resistance, repparttar 138267 greaterrepparttar 138268 amount of energy that will be absorbed by repparttar 138269 cables. The resistance will not cause any distortion, but it will decreaserepparttar 138270 volume ofrepparttar 138271 sound. The inductance onrepparttar 138272 other hand, can cause distortion. Asrepparttar 138273 current oscillates between being positive and negative,repparttar 138274 inductance slowsrepparttar 138275 current changes down, and causes delays.

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