How to Wire a Car Subwoofer?
3 Answers
It is generally recommended to install it under the middle seat of the car. When the audio is turned on, the entire car will have excellent music effects. Take power from the positive terminal of the battery, add a fuse to this wire, route the wiring harness through a suitable position into the car, and install a switch inside the cabin. The car grounds itself through the body, so the ground wire can be attached to the screws that secure the seat. You can connect wires from the original car speakers, install an audio interface, and use a dedicated audio wiring harness to plug into the subwoofer jack. After the subwoofer is installed, you can manually adjust the volume using the buttons on it and choose the sound effect that suits you best.
When I installed the subwoofer in my car last time, I found the wiring was actually quite simple. The power cable needs to be connected to the positive terminal of the battery, and remember to add a fuse in the middle to prevent short circuits. For the ground wire, choose a metal screw location on the car body and use sandpaper to remove the paint for a secure contact. The most crucial part is connecting the REM wire to the head unit's control wire, so the subwoofer only gets power when the car starts. If the head unit doesn't have a subwoofer output port, you'll need to buy a high-to-low converter and plug it into the front and rear speaker wires. Never bundle the power cable with other wires, as it will cause buzzing. I recommend using 16-gauge wire—I used this type, and a three-meter cable cost me just fifty yuan. Finally, when tuning, remember to test the phase. You can use a mobile app to play test tones and check if the bass direction is correct.
As a technician at a modification shop, I often see customers burning fuses when installing subwoofers themselves. The key point is that the power cable must be independently routed from the battery through the firewall into the cabin, with a rubber grommet added at the penetration point to prevent abrasion. I recommend beginners choose an active subwoofer kit with a wiring diagram—connect the positive power wire to the battery's red terminal using a 10mm wrench, and the black negative wire to the spare tire bolt for convenience. Using a voltmeter to check the REM wire's power status is crucial; it should show 12V when the key is turned to the ACC position. For audio sources, when adding a high-to-low converter to the factory head unit, pay attention to distinguishing the colors of the front/rear and left/right speaker wires—for Volkswagen models, white and gray are for the front doors. When adjusting the gain knob, avoid exceeding three-quarters of its range to prevent distortion.
