Speaker wire performance is gauged by Resistance, Capacitance, and Inductance. The shorter a wire is, the better, as resistance increases with length. As long as the resistance is kept to less than 5% of the speaker impedance, it will suffice for home use. The resistance of speaker connection cable in 16-gauge or heavier wire has no detectable effect in runs of 50 feet or less in most loudspeaker connections. The lower the impedance of the speaker, the greater the impact of the resistance of the speaker wire will have. High power car audio systems using 2 ohm speaker circuits need relatively thick cables. The gauge sizes in AWG (American wire gauge) reduce as the wire gets larger. Thicker wires in a cable reduce resistance. Better purification of copper reduces oxidation and results in more consistent conductivity throughout the length of cable used.