Audio Cables Information
Image credit: Grainger Industrial Supply; Digi-Key Corporation; SFCable.com
Audio cables transmit audible signals such as voice and music. They are designed to minimize noise and interference that can impair sound quality. Audio cables connect an audio source such as a stereo or microphone to an audio receiver or output such as speakers.
Types of Audio Cables
The GlobalSpec SpecSearch database allows users to select these types of audio cables.
CCTV or CATV cables are designed to transmit audio signals for closed circuit television (CCTV) systems or community access television (CATV). Bulk cable is recommended for longer runs.
Coaxial cables or coax are used for digital audio because of their relatively low cost and large bandwidth. RG6 and RG11 audio cables are inexpensive, unbalanced coaxial cables that consist of a central, metallic core surrounded by a layer of insulating material. RG6 audio cables are used in many cable television and satellite applications. RG11 cables are used as thick Ethernet (thicknet) cabling.
Fiber optic cables are relatively expensive and difficult to install, but provide near-infinite bandwidth and near-perfect immunity to noise. They are better than coax for long-distance transmissions.
Composite multi-signal cables use RCA plugs, each of which has a central male connector surrounded by a ring. The white and red cables are for audio signals, and the yellow cable is for composite video.
A cable conductor consists of a wire or combination of wires that are not insulated from each other, and facilitate the passage of electric current through the cable. Conductor-related specifications include size and number of conductors.
- Conductor size is measured in American Wire Gauge (AWG) in the United States. The higher the gauge number, the smaller the diameter and thinner the wire. Thicker wires have less resistance and are able to carry more current. Outside of the U.S., conductors are measured in mm2.
Number of conductors is usually determined by the cable's application or intended use.
Jacket and Insulation Material
Suppliers manufacture cable using a variety of jacket and insulation material in order to reduce the leakage of current from the conductor. The cable's application is an important consideration when selecting insulation material.
Ethylene Propylene Diene Elastomer (EPDM) provides excellent flexibility over a wide temperature range.
Silicon rubber provides superior flexibility but lacks toughness and fluid resistance.
Thermoplastic is an excellent insulating material. Polyethylene (PE), polypropylene, polyvinyl chloride (PVC), and Tefzel® are types of thermoplastic material. While each material has its own unique advantages and disadvantages, most are highly flexible and provide resistance to moisture or chemicals.
Most audio cables feature a type of electromagnetic shielding material, which is wrapped around the cable underneath the outer jacket. Shielding serves to prevent electrical noise from affecting the transmitted signal, and to reduce electromagnetic radiation emission from the cable itself. Shielding is typically comprised of metal braiding, metal tape or foil braiding. A shielded cable may also feature a special grounding wire known as a drain wire.
Cutaway image of a shielded cable. Image credit: Tkgd2007
When considering audio cables, buyers may specify the cable's connector type.
BNC connectors are bayonet-style locking connectors, often used to connect older computer peripherals and third party monitors. When applied to A/V equipment, it is mostly used to connect high end, high definition video equipment.
High definition multimedia interface (HDMI) is a standard A/V protocol. HDMI was developed as a digital alternative to analog standards such as RF, coax and VGA. HDMI cables connect A/V devices, such as DVD players, camcorders, and video game consoles.
High density 15 (HD-15) connectors are a type of VGA connector with 15 pins. They are mostly used to connect monitors and video cards.
USB Type B connectors are square USB connectors with 4 pins.