An additional factor that is important in the installation of a subwoofer is it’s gauge of speaker wire. The gauge of speaker wire, which are related to its thickness, determines the electrical power that will travel through the speaker wire and into the subwoofer itself. While the speaker wire creates a path for the power to travel through, if the gauge of the speaker wire is too thin, it can lead to a build-up of electrical resistance along that path and a loss of voltage over that distance of speaker wire.
The loss of voltage, then, means that there is less electrical power that the subwoofer is able to transform into sound. To avoid a loss of voltage, the speaker wire needs to be thicker, as thicker speaker wire has a lower resistance than thinner speaker wire. The American Wire Gauge, or AWG, measures the thickness of speaker wire.
How to Choose Speaker Wire for a Subwoofer
As will be explained in further detail below, a higher AWG means that the speaker wire is thinner, and a lower AWG number means that the speaker wire is thicker. There are a variety of factors that can impact what type of gauge you should use for your subwoofer systems speaker wires. Most important is the power level of your amplifier, the length of the speaker wire, and the impedance of your subwoofer.
For instance, if your amplifier is going to have to provide alot of power for your subwoofer (if it is high-powered), then you will likely need a relatively thick (low AWG) gauge of speaker wire so that the amplifier is able to provide its full power to your subwoofer; if you use too thin of speaker wire, it may not be able to provide all of that power and your audio signal will become distorted. The impedance of the subwoofer, as well, will dictate what gauge of speaker wire you will need to use. Impedance, as discussed above, is a measurement of the electrical resistance that exists within your subwoofer system.
For instance, if you have a single voice coil subwoofer that is at 4 ohms, it will require less current than if your subwoofer is at 2 ohms; the 2 ohm subwoofer, instead, requires more current and you would need a thicker gauge speaker wire to be able to handle that larger amount of current flowing through it. Using a 2 ohm load means you will need 10 AWG or thicker (lower AWG) gauge speaker wire; thin speaker wires with a high resistance will lead to a build-up of heat in these situation. Using series wiring instead of parallel wiring for your voice coils will allow you to use thinner gauge speaker wires.
The size of your subwoofer will also help to determine how thick the gauge of your speaker wire should be. A small subwoofer of 8 inches that is only using between 100 and 300 watts of power will be fine with a thinner (higher AWG) 14 AWG gauge of speaker wire; however, a large 15 inch subwoofer that requires between 500 and 2000 watts of power will need an 8 AWG or thicker (lower AWG) gauge speaker wire to accommodate for the amount of current that such a large subwoofer needs to be able to generate and move air in large quantities. In addition to these factors related to the subwoofer itself, there are also other factors related to the use of the subwoofer that may impact the type of gauge that you need for your speaker wires.
For instance, the type of enclosure that you are utilizing for the subwoofer can impact the gauge you need. A sealed enclosure means that the amplifier must exert more effort to produce audible volume from your subwoofer, so you may want to consider using a thicker gauge of speaker wire; a ported enclosure could help alleviate some of those stresses on your amplifier and speaker wire. However, a bandpass enclosure could potentially lead to issues; because heat can become concentrated when moving through that bandpass enclosure, it is likely best to use thick gauge speaker wires for those types of enclosures regardless of other considerations.
Another factor that can impact the type of gauge you need for your speaker wires is the length of those wires; if you are going to use especially long speaker wires (such as for use with speakers in an RV or bus), you are likely going to experience an increase in electrical resistance in those longer runs of speaker wire. As mentioned above, an increase in electrical resistance will lead to losses in voltage; this leads to losses in power being transferred from your amplifier through your speaker wires. If you have a longer length of run for your speaker wires, then you may need to plan on using a thicker gauge (lower AWG) of speaker wire than if you have a shorter length of run for those same speaker wires.
Finally, just as certain factors can require thicker or thinner gauge speaker wires with certain AWG ratings, it is also important to consider what type of material you are going to use for your speaker wires; some types of material have different levels of electrical conductivity and resistance than others. For instance, oxygen-free copper is going to be better than copper-clad aluminum. Since copper clad aluminum has a higher level of resistance than oxygen-free copper, it may not be as good of an option as oxygen-free copper if you’re using your audio systems with higher than 500 watts.
Additionally, you should always use wiring according to your subwoofers RMS power rating and not its peak power rating. The RMS (root mean square) power rating reflect the amount of continuous power that your subwoofer can handle, so you should of make sure you get wiring that can handle this continuous power rating so as to ensure it functions correctly with your audio system.