How to Properly Route Car Audio Wires

Introduction

Properly routing car audio wires is crucial for maintaining sound quality and ensuring your system performs at its best. Incorrect routing can lead to signal loss, interference, and potential damage to your audio components. This guide will walk you through the steps and best practices for routing car audio wires to avoid these issues.

The Importance of Proper Wire Routing

In any car audio installation, the way wires are routed can significantly impact the overall sound quality. Poor wire routing can introduce noise, cause signal loss, and even lead to electrical problems within the vehicle. Whether you're upgrading your sound system or installing a new one, taking the time to plan and execute proper wire routing can make a big difference. 

Step 1: Planning the Wire Route

Before you begin running wires through your vehicle, it's important to have a clear plan. Consider the following:

1. Shortest Path: The shorter the wire, the less resistance it will have, which minimizes the chance of signal loss. Plan the route to be as direct as possible.

2. Avoiding Interference: Keep audio cables (RCA cables) separate from power cables. Power cables can create electromagnetic interference that may cause noise in the audio signal. Ideally, run power cables along one side of the vehicle and audio cables along the other.

3. Secure Mounting Locations: Identify secure locations to mount and route your wires. Wires should be kept away from moving parts and areas that can cause friction or wear over time.

4. Protection from Heat and Moisture: Heat can degrade wires over time, so avoid routing them near the engine or exhaust system. Similarly, avoid areas prone to moisture, which can lead to corrosion.

Step 2: Choosing the Right Wire Gauge

Selecting the appropriate wire gauge is critical for minimizing signal loss and ensuring safe, efficient operation. In car audio systems, wire gauge refers to the thickness of the wire, which affects its capacity to carry current over a distance without significant voltage drop.

• 18 GA: Suitable for lower-powered speakers or shorter runs. It's often used for mid-range speakers or tweeters in less demanding systems.

• 16 GA: Ideal for standard speaker installations, this gauge is commonly used in factory setups or for aftermarket upgrades where moderate power levels are involved.

• 14 GA: A common choice for general speaker wiring in most car audio systems. It's thick enough to handle mid-range power levels and is versatile for various speaker installations.

• 12 GA: Ideal for more powerful speakers or subwoofers, where the current demand is higher. This gauge is better suited for longer runs or systems with higher wattage.

Using Copper Clad Aluminum (CCA) wire gauges in these sizes helps balance performance and cost, providing sufficient conductivity for most car audio applications while being more affordable than pure copper wires.

Step 3: Running the Power Cable

The power cable supplies electricity from the car battery to the amplifier. Proper routing of the power cable is essential to prevent signal interference and ensure safe operation.

1. Battery Connection: Start by connecting the power cable to the positive terminal of the battery. Use a fuse holder within 18 inches of the battery to protect the cable from short circuits.

2. Firewall Entry: Find a grommet in the firewall to pass the power cable into the cabin. If none are available, carefully drill a hole and use a grommet to protect the cable from sharp edges.

3. Routing: Run the power cable along the side of the vehicle, away from the audio signal cables. Secure the cable with zip ties to prevent it from moving or coming into contact with other components.

4. Grounding: Choose a solid, clean metal point close to the amplifier for grounding. Use a short, thick ground cable (the same gauge as the power cable) and ensure the connection is secure to prevent ground loop noise.

Step 4: Running the Signal Cables

Signal cables (RCA cables) carry the audio signal from the head unit to the amplifier. Proper routing is key to avoiding noise interference.

1. Keep Away from Power Cables: As mentioned earlier, always run RCA cables on the opposite side of the vehicle from the power cables. This reduces the risk of picking up noise from the power line.

2. Secure Routing: Route the RCA cables through the vehicle's interior trim, keeping them away from sharp edges or areas where they could be pinched. Secure the cables with clips or zip ties to prevent them from shifting.

3. Connection Points: Ensure that RCA connections at both the head unit and amplifier are tight and free of corrosion. Loose or dirty connections can cause noise and signal loss.

Step 5: Speaker Wire Routing

Proper routing of speaker wires is just as important as power and signal cables. Speaker wires carry the amplified signal to the speakers and must be routed carefully to maintain sound quality.

1. Avoid Pinching: Route speaker wires through the door jambs or under the carpet, ensuring they are not pinched or bent sharply. Pinched wires can break or cause a short circuit over time.

2. Maintain Polarity: Consistently match the positive and negative terminals on the amplifier to those on the speakers. Incorrect polarity can cause phase issues, resulting in poor sound quality.

3. Wire Protection: Use wire loom or conduit to protect speaker wires in areas where they might be exposed to wear or damage. This is particularly important in doors, where wires move with the opening and closing.

Step 6: Final Testing and Troubleshooting

After routing all the wires, take the time to test the system before fully reassembling the vehicle interior. Check for the following:

1. Sound Quality: Play audio at various volumes and listen for any distortion, noise, or imbalance. If you detect issues, check the routing and connections of the signal and speaker wires.

2. Electrical Noise: Turn on the car and listen for any whining or buzzing sounds that may indicate interference. If present, double-check the separation of power and signal cables.

3. Secure Connections: Ensure all connections are tight and secure. Loose connections can cause intermittent issues that may be hard to diagnose later.

Conclusion

Properly routing car audio wires is essential for achieving optimal sound quality and system reliability. By planning your wire paths, choosing the right wire gauge, and following best practices for routing and securing cables, you can avoid common issues like signal loss and interference. Using quality CCA wire gauges and carefully considering each step of the installation will help ensure that your car audio system delivers the best performance possible for years to come.