We all know cable shielding is important to ensure a good quality of signal reaches its destination, but it’s worth taking a fresh look at some of the potential sources of interference in a common home entertainment set-up. F
or instance, if you’ve ever held an unshielded speaker close to a CRT computer monitor, you’ll know how strong the magnetic field that they produce can be (and it’s not recommended to expose your monitor to that kind of abuse…!).
But when a magnetic field and an electrical cable intersect, you get an induced current – and this is where interference can come from. Likewise, an electrical current passing along a cable can create a magnetic field of its own, which can in turn cause interference in neighbouring wires.
Cable shielding thus protects the carried signals not only against any nearby physical magnets, but also against electromagnetic induction from power cables, data connections, and even the mains loop inside any nearby walls – not to mention wireless signals that might cause interference too. If you can’t predict the exact circumstances in which your cable will be used, it’s wise to invest in some shielding, to compensate for all of these environmental effects once it’s connected and transferring power or data.