How To Determine What Gauge Wire To Use For Speakers

Speaker wires are responsible for sending uninterrupted electrical signals from an amplifier like an AV receiver to a speaker.

The gauge of the wire you use for your setup can be the subtle difference between a home theater system capable of delivering consistent, clear, and powerful sound and one that leaves you questioning your investment.

That’s why using speaker wire with the right gauge size is one of the most important things you can do when putting together an audio system.

You can have the latest and greatest floor-standing speakers or the best bookshelf speakers on the market—if you’re wiring them wrong, you’ll have a sound quality nightmare.

So, which gauge speaker wire should you be using to connect to your speakers?

We’ll break this down in our article, but to get you a quick answer, use this table to help you determine which gauge to use:

Speaker Wire Gauge Size Based on Speaker Impedance and Length of Run

Distance to Speaker (ft)	4 ohms	6 ohms	8 ohms
5	18 AWG	18 AWG	18 AWG
10	18 AWG	18 AWG	18 AWG
20	16 AWG	18 AWG	18 AWG
30	16 AWG	16 AWG	18 AWG
40	14 AWG	16 AWG	16 AWG
50	12 AWG	14 AWG	14 AWG
60	12 AWG	12 AWG	14 AWG
70	10 AWG	12 AWG	14 AWG
80	10 AWG	12 AWG	12 AWG
90	10 AWG	12 AWG	12 AWG
100	10 AWG	10 AWG	12 AWG

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Understanding Wire Gauge and AWG

The term “gauge” indicates the thickness or diameter of a wire. It’s standardized by the American Wire Gauge (AWG) system, which assigns dimensions based on a numerical scale.

The lower the gauge number, the thicker the wire. Speaker wires are typically labeled as 10, 12, 14, 16, or 18 gauge, with a 10 gauge wire being the thicker option and an 18 gauge being the thinner wire.

Why Gauge Size Matters

Choosing the right gauge size for your speaker wire matters because this wire directly affects the audio signal between your amp or receiver to your speakers. Using the wrong wire will impact the audio quality and the amount of power delivered to each speaker.

The goal is to make sure your speakers have minimal electrical resistance and enough power going to each speaker so they can run at maximum volume with as little distortion as possible.

Electrical Resistance

The further you run a speaker wire, the more electrical resistance there is.

In a perfect world, a speaker cable wouldn’t have any electrical resistance at all, allowing audio signals to pass through perfectly from an amp or receiver to the speaker with as much power as possible.

However, the James Webb telescope has yet to stumble upon this perfect world, so in the meantime, your goal should be to keep resistance to a minimum.

Power Handling

You also need to make sure the wire can transfer enough power to your speakers so they can perform at their best.

When power travels through a wire, a portion of it is dissipated in the wire itself rather than reaching the speaker. The thicker the wire, the more power it can transfer.

If you love cranking up the volume or want to drive larger speakers without risking distortion or damage to your system, you need to use a wire that can handle the maximum power output of your amp.

Using a wire that’s too thin for a high-power setup can lead to overheating and potential damage to both the wire and your system.

How to Determine What Size Wire You Need to Use For Your Speakers

When hooking up an audio system, two of the most important factors to consider are how far you plan to set your speakers from your amplifier or receiver and the impedance of each speaker.

These two variables combined influence how much resistance a wire will have and how well it will carry the audio signal. Once you know the distance and the impedance of your speakers, you can determine what gauge wire to use.

For home audio systems with bookshelf speakers, floor-standing speakers, or satellite speakers, it’s recommended to use a speaker wire with a gauge size large enough to keep the electrical resistance under 5% of the speaker’s impedance.

Here’s a way you can calculate this yourself based on your setup:

How To Calculate What Gauge Wire To Use for Speakers

Use this calculation to figure out what gauge size you need for your speaker wires or to confirm that the cables you have are sufficient enough:

Step 1: Find The Speaker Impedance

Different speakers have different impedance ratings, which are measured in ohms. Look for the label showing your speaker’s impedance rating somewhere on the speaker.

This is usually located on the back of the speaker. Common impedance ratings are 4 ohms, 6 ohms, or 8 ohms.

Step 2: Calculate 5% of The Speaker Impedance

Next, multiply the speaker impedance by 5% (0.05). For example, if your speaker impedance is 8 ohms, the calculation would look like this:

8 ohms × 0.05 = 0.4 ohms

This means the resistance of the wire you use to connect the speaker should be less than 0.4 ohms.

Step 3: Determine The Wire Resistance

Wire resistance depends on the gauge of the wire and the length of the wire. Thicker wires will have less resistance. Here are the resistance levels per foot for copper AWG gauges:

Gauge Wire	Electrical Resistance Per Foot
10 Gauge	0.0009
12 Gauge	0.0015
14 Gauge	0.0025
16 Gauge	0.0040
18 Gauge	0.0063

Step 4: Calculate The Total Resistance for Your Wire

Multiply the resistance per foot by the total length of your wire run to and from your speaker.

For example, if you’re using 16 gauge wire and your speaker is 50 feet away, you would use 0.0040 per foot as the resistance:

Distance to Speaker x Electrical Resistance x 2 = Total Wire Resistance

50 feet x .0040 x 2 = .4ohms

In this example, the total wire resistance = .4 ohms

Step 5: Compare The 5% Value to The Total Wire Resistance

Now, take this number and compare it with the 5% value you calculated from your speaker’s ohms. If this wire resistance number is less than 5% of the speaker’s ohms, then the gauge wire is appropriate to use.

Let’s look at a full example of how to calculate this:

Let’s say you have a set of speakers you want to place 65 feet away from your amplifier. One speaker is 4 ohms, and the other is 8 ohms.

We’ll start by finding the 5% value for each one.

Speaker 1 (4 ohms): 0.2
Speaker 2 (8 ohms): 0.4

Now, we can go through the wire gauges to determine which one would be the correct size to use:

10-gauge wire (0.0009 resistance/per foot): 65 x 0.0009 x 2 = 0.11 ohms
12-gauge wire (0.0015 resistance/per foot): 65 x 0.0015 x 2 = 0.19 ohms
14-gauge wire (0.0025 resistance/per foot): 65 x 0.0025 x 2 = 0.32 ohms
16-gauge wire (0.0040 resistance/per foot): 65 x 0.0040 x 2 = 0.52 ohms
18-gauge wire (0.0063 resistance/per foot): 65 x 0.0063 x 2 = 0.81 ohms

Based on the calculations:

Speaker 1 will need to be installed with at least a 12-gauge wire.
Speaker 2 will need to be installed with at least a 14-gauge wire.

Wire Material Used to Connect Speakers

There are three main materials used for speaker wires: copper, copper-clad aluminum (CCA), and oxygen-free copper (OFC).

Copper

Copper is the most common material used for speaker wires in both home entertainment systems and professional audio environments. This is because it offers low resistance and excellent conductivity.

These properties allow audio signals to be transferred efficiently, resulting in clear and high-quality sound output that is reliable and consistent.

Copper-Clad Aluminum (CCA)

Copper-clad aluminum wires are an alternative to pure copper wires. They’re less expensive but also have higher resistance than pure copper.

To achieve the same performance as a pure copper wire, a thicker CCA wire is needed.

Oxygen-Free Copper (OFC)

Oxygen-free copper (OFC) wires are crafted using a purer form of copper with fewer impurities. This can marginally enhance conductivity and decrease oxidation over time.

However, the impact on audio performance compared to standard copper is minimal.

OFC wires are commonly promoted for high-end audio systems, but their advantages are mainly related to durability rather than substantial enhancements in sound quality.

Tips for Wiring Speakers for a Home Theater

1. Avoid Interference

To minimize interference, avoid running speaker wires parallel to electrical cables. If you have to cross an electrical cable, try to cross it at a 90-degree angle. This will reduce the chance of electromagnetic interference affecting the audio signal.

2. Use Good Connectors

Secure the wire to your speakers and amp using high-quality connectors like banana plugs, spade connectors, or pin connectors. These reliable connectors prevent signal loss and help maintain the audio quality.

3. You Can Use Different Gauges of Speaker Wire for Separate Speakers

If you have a mix of different gauged speaker wires running to separate speakers, that’s fine.

You might run into this scenario if you’re upgrading to a new surround sound system. Just make sure the gauge is thick enough to handle each speaker at their respective lengths.

It also doesn’t matter if you have the same gauge speaker wire going to all of your speakers. If you’re installing a new audio system, just let the speakers furthest away from your receiver dictate what gauge size you use.

You’ll likely have enough wire left over to run everything, and you’ll save money by buying one roll of speaker wire at a specific gauge size rather than multiple rolls at different sizes.