Cables and Connectors
Dec 10, 2012 4:13 PM, By Mark Johnson
Let’s face it, you can have the best electronics going, but if it’s not connected to anything else, it really isn’t worth much. Cables and connectors are the lifeblood of electronic gear and each component (audio, video, data, etc.) requires its own specialized connection. For connectors, good metal-to-metal for data signal transmission and a secure fit into its mating device is key, while durability is paramount in portable applications where connectors can be subjected to frequent patching and unpatching.
THE CANNON CONNECTION
The XLR microphone cable, probably the most common cable/connector combination employed in pro audio, is used to connect mics to mixing consoles as well as to interconnect pieces of equipment. James Cannon, founder of Cannon Electric, invented the XLR, hence the occasional reference of the connector by some of the more mature people in the audio industry as a “Cannon connector.” The original designation of the connector was the Cannon X series. A latch was added to the design and the designation changed to include that configuration (XL). The “XL” was amended with “R” when the female contacts were embedded in a resilient polychloroprene.
The cables, whether used for installation or portable audio applications, share the same basic form factor: one or two twisted pairs (also known as “Star Quad”) of individually insulated wire with a shield that is either braided, spiral wrapped (serve), or foil, and an insulating jacket. Serve shields help to provide flexibility but can open up when the cable is bent. Braid shields provide more consistent coverage and remain closed. The braid shield provides better electrical performance and greater pulling strength.
AUDIO AND DATA CABLING
Invented by Alexander Graham Bell, the twisting of the conductors helps to improve the common mode rejection ratio (CMRR)—reducing hum and buzz from transformers, fluorescent ballasts, and silicon-controlled rectifier (SCR) dimmers— and helps to reduce crosstalk from any adjacent pairs. The tighter the twists, the better the CMRR is. Star Quad cables use two twisted pairs, twisted together in place of a single pair of twisted wires. This allows electromagnetic interference (EMI) to be reduced by as much as 20dB over a typical single twisted-pair mic cable.
While seemingly disparate, audio and data cabling are now linked by virtue of the overwhelming amount of professional audio electronics that can be networked, monitored, or controlled via a web interface.
For networking, the cable of choice is the Ethernet cable. Sometimes referred to as “unshielded twisted pair” (UTP), Cat-5 and Cat-5e (enhanced) are probably the most common for networking audio gear, however, Cat-6 offers increased performance. Like its audio brethren, Ethernet cables are made up of twisted wires (there’s just more of them to a cable) and there is no shield. Cat-5 cables can be made up of four twisted pairs of either solid or stranded wires, with an application rule of thumb for the solid being used for long runs and the stranded used when flexibility is required. Cat-5 cable is designed to support 10 Mbps or 100Mbps Ethernet with a capability of up to 100MHz. Cat-5e provides lower levels of near-end crosstalk (NEXT) than Cat-5, and supports Gigabit Ethernet. Providing twice the bandwidth of Cat-5, Cat 6 supports 10GB Ethernet and operates up to 250MHz. Cat-6 cables still use four twisted pairs of wire, though a longitudinal separator isolates each of the pairs, reducing crosstalk and allowing faster data transfer. The good news is Cat-6 is backward compatible with Cat-5 and 5e, so upgrades and expansions can be readily accommodated.
Atlas Sound product group, Atlas Signal, features the AS2XLR in three lengths: 3 meters, 10 meters, and 15 meters. The cables comprise an ergonomic, professional-grade XLR connector with integral strain relief, braided copper-clad aluminum shielding, and a pliable, high-quality cable jacket.
Atlona high-quality Cat-6 cable is designed to support full 550MHz, network applications for 10 to 100Base-T networks and comply with TIA/EIA standards. The cable features four 26AWG pairs of conductors, snagless PVC jacket, molded-strain relief, and 24K gold-plated connector. The cable is available in 10ft. lengths.
Audio-Technica AT8314 series premium microphone cables are designed for low-impedance operation. These balanced cables feature heavy duty, 24-gauge stranded copper conductors and professional Neutrik connectors. Each conductor has an individual spiral shield inside the molded insulating sheath. A conductive PVC layer inside each shield dissipates static buildup during flexing. They are available in lengths ranging from 1.5ft. to 100ft.
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