A speaker wire is used to transmit audio signals from a loudspeaker to an amplifier. It is normally made up of two wires that are each wrapped in plastic for insulation. Copper is commonly used as a material for a speaker wire, because of its lower resistance, and it costs less than the other materials that can be used as wires. A speaker wire's resistance needs to be at least 5% of its speaker's opposition to the alternating current, in order for it to have reliable performance.
There are a lot of ways to measure a speaker wire size. You can use the Standard Wire Gauge, also known as the Imperial Wire Gauge or as the British Standard Gauge, or the American Wire Gauge, AWG. The American Wire Gauge or the Brown and Sharpe wire gauge is commonly used to measure a wire's size. American Wire Gauge sizes can go from 40 AWG up to 0000 (4/0) AWG. The Standard Wire Gauge is commonly used now in measuring electrical strings. But here are the commonly used stereo wires nowadays, and when to use them.
- 12 AWG or 12 gauge. This speaker cable has a size of 0.0808 inches (2.053 mm) in diameter and has an area of 6.53 kcmil. It has a copper resistance of 5.211 Ohm/km. If you need a speaker wire connector to be more than 200 feet, it is recommended that you use this gauge of speaker wire. Reviews show that this is best to be used if you are installing a surround sound home theater system, or if you are going to install speakers that are going to run from one room to another. This type of speaker wire is harder to get covered though, so you'll most probably drill holes in your wall to facilitate it.
- 14 AWG or 14 gauge. This speaker cable has a size of 0.0641 inches (1.628 mm) in diameter and has an area of 4.11 kcmil. It has a copper resistance of 8.286 Ohm/km. If the distance from your speaker to your amplifier is from 80 to 200 feet, it is recommended that you use this gauge of speaker wire.
- 16 AWG or 16 gauge. This speaker cable has a size of 0.0508 inches (1.291 mm) in diameter and has an area of 2.58 kcmil. It has a copper resistance of 13.17 ohm/km. This gauge of speaker wire is recommended to use if the distance from your speaker to your amplifier is less than 80 feet.
The rule of the thumb is, the lower the gauge, the thicker the wire, and the better its audio transmission will be. Keep your speaker wires as short as possible to be more effective. If you really need a long speaker cable, use thicker ones to make up for the transmission lost because of its length. So when you are buying a speaker, check the wires that come with it. Some speakers use non-standard plug-in connections, making it impossible for the wires to be changed. It won't hurt to look for better wires for your speakers if it is possible to have them replaced.