Even in the wireless audio age, speaker wire is still critically important for powering sound in your individual spaces. Gauge, distance, code compliance and wire types affect performance and safety, all major factors when selecting cable. In the sea of speaker wire selection, choosing copper, silver gauge and run distance all matter. Banana plug and spade terminal connectors dress up wires, making them easier to connect to your amplifier or receiver.
Gauge and Resistance
The thickness of speaker wire is measured in AWG, or American Wire Gauge. The smaller the number, the more strands comprise the cable. For example, 10-gauge speaker wire is one size larger than 12 gauge. For most speaker runs up to 10 feet, 18 gauge is adequate. For runs up to 100 feet, 16 gauge is sufficient and so on. Using a wire gauge that is too small for the needed distance affects bass response and fullness of sound due to increased electrical resistance. Remember that speakers come mainly in 8, 6 and 4 ohm impedance. As impedance drops, power requirements increase proportionally. For example, if 18-gauge wire works with an 8- or 6-ohm speaker at 10 feet, 16 gauge is required for a 4-ohm speaker. Note the impedance indicated on the sticker on the back of your speaker prior to selecting speaker wire gauge.
Solid vs. Stranded
Stranded and solid-core speaker wires are readily available on the market, potentially causing confusion. Solid-core wire reduces cable resistance, especially in designs that individually insulate each conductor. This is primarily because each strand of wire in that type of configuration must account for air pockets and inter-strand interactions between each filament. Solid-core wires only need to have consistent copper grains, which is manipulated as the copper is formed into wire at the factory; however, the cost difference between a spool of this speaker cable and a stranded 12-gauge option can be significant. The high-current AC power lines in your home use solid-core wire. Disadvantages include increased cable stiffness and a tendency to break if repeatedly flexed.
As you shop for wire, you will notice two- and four-conductor wires with a "CL" marking on the spool and jacket. This indicates that the wire is supplied with a special outer jacket that resists open flame. Favored by electrical inspectors, CL-rated speaker wires commonly have smoother outer jackets, facilitating pulls through studs and tight spaces. Four-conductor options allow wiring of a pair of in-wall or in-ceiling speakers with one cable pull, reducing installation time by half. The copper inside this wire type is usually stranded, with very low oxygen content to reduce oxidation over time.
Flat wire is useful in environments where tucking wires behind walls or baseboards is impossible or impractical. This wire is normally 16 or 14 gauge and is designed for tacking or adhering to a wall. Once the wire is installed, you can conceal it against the wall using paint or stain. Flat wiring might be a little more expensive compared to a similarly gauged wire but is often a lifesaver in older homes or apartments.
Banana plugs, spade connectors and braided wire terminations offer a few advantages. Whether the termination crimps, twists or locks on via a threaded two-piece connector, terminations help keep oxygen out and ensure that the contact from speaker to amplifier is pure. In addition, terminations allow a clean, finished look, simplifying connection to an amp or speaker. The chance of a short circuit from a stray wire touching an amplifier's chassis is eliminated by containing all of the individual strands within the termination's shell. Solid-core wires cannot be used with crimp connectors but instead require terminations that secure by means of set screws that bite into the copper.
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