A cable is actually a conductor used for transmitting optical or electrical signals or electric power from one device to another. As far as Audio Cables are concerned, they are flexible connectors that provide physical joining between an Audio Amplifier and Loud Speakers. As we see today, the contemporary Audio Cables are made up of two or more electrical conductors which are individually shielded by different types of plastics, for example, Polyvinyl chloride, Polyethylene, or Polytetrafluoroethylene (commonly known as Teflon). The insulations of these two cables are usually marked so that they can be distinguished. The reason behind that is that they may be electrically identical, but they have just the opposite polarity.
Audible signals like Music and Voice are conveyed by these cables. These cables are especially designed in such a way that they do not allow noise and other sort of external interferences to add up and deteriorate the quality of the original Audio. They are used to connect the outputs of a Stereo Player or a Microphone with the inputs of a Speaker or an Audio Receiver. The conductors inside the cable can also be provided with a covering of a thin laminated and flexible sheet metal or a piece of interwoven cloth to avoid Electromagnetic interferences.
There are different types of Audio Cables available in the market, and each of them has its own distinctive application. Below, I am about to discuss some of most popular types that you must have seen.
Closed-circuit or Cable-television cables - These cables are made to carry audio/video signals of a Closed-circuit Camera or a Cable Television.
Coax or Coaxial cables - They are lower in price but, amazingly, they are good for greater Bandwidths. This is the reason they are specifically used for Digital Audio Signals. RG11and RG6 cables are low-cost, unbalanced coaxes that are made up of a central, metallic core enclosed by a thin film of insulating material. RG11 is considered good for providing thick Local Area Network cabling, whereas RG6 is used for various Satellite applications and Cable Televisions.
Optical Fiber cables - Although, Optical Fibers are not install-easy and the price is also somewhat on a higher side, they are used for precise signaling operations. These cables are immune to the noise and offer nearly infinite Bandwidth. They are highly recommended for long distance communications.
Composite (multi-signal) cables - You must have seen these colorful cables with your Audio/Video devices. RCA connectors are used at both the ends of these cables. White cable is for the composite video, whereas the Red and White are for Audio signals only.
Audio Cables can be specified according to the Size of the conductor, Material of the insulation used, and the type of the Shielding used in cable. In United States and Canada, the unit for measuring Cross-sectional area of the conductor is AWG (American Wire Gauge). It is also widely known as the Brown & Sharpe wire gauge. In other countries, the unit for measuring this is Square Millimeters (sq. mm). Elastomers or Thermoplastics are used in most of the Audio cables for insulating them from each other. Some of the insulating materials are Silicon Rubber, PVC, PP, PE, and EPDM. As far as Cable shielding is concerned, it has four basic types, namely, Foil Braid, Foil or Copper Tape, Copper Wire or Drain Wire, and Braid.