Speaker cable has a straightforward job: to transfer power from a receiver or amplifier to a speaker. However, making poor choices in speaker cabling can impact audio performance in key ways. Speaker cables vary from basic wires on a bulk spool to esoteric models costing thousands. Understanding the physics behind speaker cables will help you make an educated decision.
Measure the distance between your receiver or amplifier and each speaker. Speaker wire gauge is determined by these findings. Speaker wire is normally 18, 16, 14, 12 or 10 gauge. Under 10 feet, 18 gauge wire is sufficient. At 20 feet, 16 gauge is permissible, all the way up to 100 feet at 10 gauge. As distance between the receiver and the amplifier increases, so should the wire gauge.
Examine your speaker's impedance. This is denoted by a numeral teamed with a symbol resembling an inverted horseshoe. Most home speakers are 4, 6 or 8 Ohms. If your speakers are 4 Ohms, whatever distances the wire can travel at a certain gauge is divided by half. For example, if your 16 gauge speaker wire can travel 10 feet without loss at 8 Ohms, with a 4 Ohm speaker that becomes 5 feet.
Look at CL rating. This tells you that the speaker wire is up to electrical code. CL-rated wire is often coated in a slick jacket that assists in pulling through studs when wiring in-wall and in-ceiling speakers. The rating comes from the jacket's ability to resist combustion when exposed to direct flame. This prevents the wire from becoming a wick, carrying flame from room to room in the event of a fire.
Look for wire that is designed for audio use. Basic lamp cord, while effective, is often covered with a jacket that does not keep out oxygen as effectively. Oxidation can affect audio performance over time, indicated by a green or brown appearance on the wire under the jacket.
- Terminate speaker cables with screw or crimp-on terminations. In addition to making it easier to connect to a receiver to amplifier, terminations prevent stray wire filaments from causing a short through contact with the amplifier chassis.
- If in doubt, use the lowest-gauge wire you can afford.
- Do not worry about precisely matching wire length. Audio signals travel along a wire at close to the speed of light. One length would need to be miles longer than the other to notice an appreciable difference.
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