car audio

Basic knowledge of car audio wiring

As the car will produce a variety of frequency interference while travelling, the listening environment of the car’s audio system can be adversely affected. Therefore, the installation of the car audio system wiring has specific requirements.

1, Power line wiring

The current capacity value of the selected power cord should be equal to or greater than the value of the fuse connected to the amplifier. If a lower standard wire is used as a power cord, it will produce AC noise and seriously affect the sound quality. The power cord may overheat and catch fire.

  • When using one power cord to supply power to multiple amplifiers separately, the length of the wiring from the separation point to each amplifier should be as uniform as possible.
  • When the power cord is bridged, there will be a potential difference between the amplifiers, which will cause AC noise and seriously damage the sound quality.
  • When the host is powered directly from the power supply, it will reduce noise and improve sound quality. Thoroughly clean the dirt from the battery terminals and tighten the connections. If the power connection is dirty or loose, the connection will be poor, resulting in flowing impedance and causing AC noise that seriously affects the sound quality. Use sandpaper and fine sawdust to remove dirt from the terminals and apply some grease.
  • When wiring within the car’s power system, avoid wiring in the vicinity of the generator and ignition devices as their noises can radiate into the power lines.
  • When replacing the original installed spark plugs and ignition cables with high-performance types, the ignition spark will be stronger, making it more prone to ignition noise.

2, Grounding method

Use fine sandpaper to remove the paint from the vehicle’s grounding point and secure the grounding wire tightly. Residual car paint between the vehicle body and the grounding point can cause electrical resistance. Similar to the dirty battery connections described earlier, electrical resistance can lead to the generation of AC noise, seriously damaging sound quality. Concentrate the grounding of each audio equipment in the sound system at one point. If they are not grounded at one point, potential differences between the audio components can cause noise.

3, The choice of car audio wiring

The resistance of car audio wiring affects the power consumption and efficiency of the entire system. When the resistance is lower, less power is consumed by the wiring and the system is more efficient. Even if the wiring is thicker, the inefficiencies of the speakers themselves will cause power loss, preventing the system from achieving 100% efficiency.

The lower the resistance of the wire, the greater the damping coefficient. The greater the damping coefficient, the greater the superfluous vibration of the speaker. The larger the cross-sectional area of the wire (i.e. thickness), the lower the resistance and the larger the wire’s tolerance current. This allows for a larger allowable output power. Power insurance should be selected from the main power line fuse box that is closer to the car battery connector. The size of the insurance value can be determined according to the following formula: Insurance value = (the sum of the rated power of all the amplifiers in the system¡ 2) / the average value of the car power supply voltage.

4, Audio signal line wiring

To ensure insulation at the joint of the audio signal wire, wrap it tight with insulating tape or heat shrink tubing. When the joint contacts the vehicle, it can produce noise; therefore, keep the audio signal wire as short as possible. The longer the audio signal wire is, the easier it will be to interfere with various frequency signals inside the car. Note: If it is impossible to shorten the length of the audio signal wire, fold the extended part rather than roll it up.

The wiring of the audio signal line should be at least 20cm away from the power line of the driving computer module circuit and amplifier. If the wiring is too close, the audio signal line will pick up noise from frequency interference. It is best to separate the audio signal line and power line and place them on either side of the driver’s seat and the passenger’s seat. Note that when nearing the power line and microcomputer circuit wiring, the audio signal line must be at least 20cm away from them. If the audio signal line and power line need to cross each other, we recommend a 90-degree intersection.


Car audio wiring should follow specific principles to avoid noise and interference that may affect sound quality. The power cable must meet the required standards, the grounding should be firm and reliable, and the audio signal cable should be as short as possible and far away from potential sources of interference.