Hearing from people who want to ensure that they’re using the correct size (gauge) of speaker wire is like music to our ears because those people are going to get the best performance out of their car audio equipment, their equipment is going to last longer, and it can even be safer in some circumstances, versus using wire that’s too small.
When you stop and think about it, the wiring in your system is absolutely crucial. Think of it like a highway. It’s better to be the only car on a 4-lane highway than to be the 900th car lined up on a one lane highway. In other words, it’s perfectly fine to get wire that is a bit thicker than you need. Going too thick will make it harder to work with and to maneuver at a certain point, but not thick enough is much worse.
Wire Size 101
Let’s quickly go over some of the different sizes and types of wire that are common to find in car audio installations, and then we’ll talk about how to match them up with your amplifier of choice.
For all of the discussion that exists surrounding the gauge of the wire, the materials it’s made from, and certain marketing buzzwords… at the end of the day, it all comes back to resistance.
This can vary from gauge to gauge, manufacturer to manufacturer, and material to material. Having said that, there are still recommended gauges for different uses that serve as a rule of thumb and a best practice. Thicker wires (lower gauge) generally offer less resistance, meaning that more electricity can travel through them and that they can deliver more power to your equipment at any given moment.
You’ll see anything from 1/0 gauge wire to 18 gauge wire used in car audio installations, depending on what it’s used for. The closer the wire is to the battery in the series, the thicker it’ll usually need to be, because in between the battery and the amplifier will have the biggest demand for power.
Take a 4 channel amplifier for example. The current needed to power those 4 channels is entering the amplifier in just one wire, and then being distributed to your speakers using 4 separate paths, so those 4 paths don’t need as low of a resistance as the wire going directly to your amplifier.
Why it matters
When you use wires with too low of a resistance, your equipment won’t be getting the power it needs. Also, when you’re trying to force through more electricity than the wires can handle, it creates extra heat which can lead to a litany of problems.
Choosing the Best Size Wire for Your Amplifier
Let’s start with the size of the power wire that goes into your amplifier, and then we’ll look at the size of wire that leaves your amplifier and goes to your speakers. Keep in mind these are rules of thumb, but the following options will give you enough flow of current to power your devices.
For smaller amplifiers at 250w RMS or less, 10 AWG wiring will be just fine.
For amps in the 250-500w RMS range, you’ll want to bump that down to 8 AWG.
When we get into the 500-1000w RMS range, we’re starting to deal with a lot more power, and this is where you’ll want 4 AWG.
Finally, for amplifiers that are 1000w RMS or more, you may as well make the jump to 1/0 AWG. It’s thick, and not as easy to work with, and it’ll cost a lot more – but it’ll also have no problem powering the beefiest of amplifiers.
For the speaker wires themselves, it’ll depend on how many channels your amplifier has and how much current is flowing to each one.