Basic Cable: Choosing the Right Cables for Your System
Many people spend a lot of time selecting their gear with barely a thought to how they're going to hook everything up - until it's unpacked in the living room. In a modern A/V system, however, making the right connections can have a big effect on what you see and hear.
That doesn't mean you have to spend a fortune on cables. But you can do yourself a real favor by figuring out which types of audio and video connections are optimal for the equipment in your system and ensuring that the cables you use to make those connections are well-constructed and have the proper electrical characteristics. This can buy you not only visual and sonic improvements but also the peace of mind that comes with not having to troubleshoot annoying buzzes, hums, or flat-out signal failures.
Cable Fundamentals Aside from speaker wires, which are normally simple insulated (but unshielded) pairs of copper conductors, there are three types of cables: twisted-pair, coaxial, and fiber-optic. Both twisted-pair and coaxial cables carry signals along copper wires, while fiber-optic cables carry signals modulated as pulses of light along strands of glass or transparent plastic. Twisted-pair cables, used mainly in phone networks and Ethernet connections, have pairs of independently insulated wires twisted around each other, which helps fend off noise from adjacent wires (crosstalk) as well as outside electrical interference. Coaxial cables have a core wire (called the conductor) surrounded by an insulating material (called the dielectric), plus a layer of electrical shielding and a plastic or nylon outer jacket. Fiber-optic cables consist of a glass- or plastic-fiber core, cladding (which helps keep the light pulses within the fibers), and an external jacket.
Twisted pair - used in Cat-5e cables, for instance - is relatively inexpensive and easy to install, but it's susceptible to electromagnetic and radio-frequency interference (EMI and RFI, respectively). Coax can support a wider frequency range and has better shielding against interference, but it can still pick up EMI or RFI in difficult environments or induced hum from nearby power cables. Fiber-optic cable has great bandwidth and is completely immune to EMI and induced hum, but it's costlier and more fragile.