To decide what speaker-cable-gauge for your audio system you need to consider the size of your audio system, the length of the cable between the speaker and the amp, and also the quality of the cable itself to get the best performance from your audio system. The gauge thickness identifies speaker cable, and it tends to be at 12-16 gauge for car audio system, the lower the number the thicker the cable that can also handle high level electrical current more efficiently.
Decide how long the cable will be from each speaker to the amp, longer cable run need a thicker-gauge cable to get the best result and create less strain on the amp and receiver.
A general guide in the average car audio set up are the use of 12-gauge cable on up to 30-foot runs; 14-gauge cable on up to 18-foot runs; and 16-gauge cable on up to 10-foot runs, remember these figures are based on a 4-ohm resistance load.
Decide the quality of the cable, if you’re using a high quality components for the amp, speaker, and head unit in your car, make sure to use a high quality cable also. This will cost you more but will also create the best sound quality, it’ll also last longer, and more resistant to interference from other audio cable in your system. When it comes to wiring, the price will tell the truth.
