How To Set Up a Subwoofer in a Car like a Pro

I know there are things that should be left to the professionals. Just like playing basketball, conducting surgery, and installing car audio.

But it isn’t wrong to try it for ourselves, right? Well, except surgery, of course (unless you’re a surgeon reading this). Which is why I am writing this DIY article on how to set up a subwoofer.

Tedious as it may seem, installing car audio by yourself gives you the gratification that’s worth so much more than the sweat, tears, and grease you churned out in the process.

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Tools for Setting up Subwoofers for Your Car​

  • Torx driver
  • Nut driver
  • Allen wrench
  • Utility knife
  • Drill
  • Crimping tool
  • Panel removal tools
  • Cable tie
  • Split loom
  • Electric tape

As much as possible, stick with the tools and wires listed above. Otherwise, getting an alternative may give you an unwanted result.

Pro tip: Make sure the specs of your amplifier and subwoofers match. You want no electronic barbecue in your car.​

Setting up Subwoofers​

  1. Inspect your car. You don’t have to hire the CIA to do this although you probably have to act like one. Start off by checking your car’s electrical system. You are going to modify it a bit, so it’s just right to know what’s working and not before adding your amp and subwoofer.​
  2. Some things you have to take note of are:

    • Cigarette lighter
    • Climate control
    • Gauges
    • Hazards
    • Heated seats
    • Lights both interior and exterior
    • Mirrors
    • Power windows
    • Turn signals
    • Wipers​

    Pro tip: List them down using a pen and paper or any note taking app you find handy. You know, just in case you have a senior moment.

  3. Tinker with the battery. Start off with opening your hood finding the battery somewhere there sitting comfortably. Then locate the battery terminals. They’re usually protected by a foam or plastic cover.
  4. Pro tip: You may want to use a thick covering such as a fender cover from this point on to protect your car’s paint.

  5. Find a hole. After finding the battery terminals, find a space in the firewall where you can run a wire through to reach the car’s interior. You may go inside the car and see where the wire from the hood will exit.
  6. Pro tip: You may use one of the cables to check clearly.

  7. Poke a hole. Using any of the drivers, poke (or just push) a hole through the rubber grommet while you’re inside the car.
  8. Pro tip: Leave the nut/screwdriver there, so the hole is kept open.

  9. Prepare the power wire. Start by removing the fuse from the power wire. Then from the outside, locate where you poke a hole with grommet tool and insert the power wire into the hole. Do this until a significant length of the wire is inside the car.
  10. Pro tip: Use a small tray or any container for the fuse so as not to misplace it.

  11. Get some power. This step is for hooking up the power wire to the battery. Begin with removing the nut from the battery terminal you found a while ago. Next, place the power cable on top of the already placed cable. Then, replace the nut and secure it in place properly.
  12. Pro tip: Use a cable tie to make sure the wires inside the hood do not get in the way of the other parts.

  13. ​Run the power wire. Go inside the car and run the wire where it doesn’t obstruct any of the car’s interior parts, especially the steering wheel. Run it all the way through the car until it reaches where you plan to place your amp.
  14. When running the power wire along the areas that will get in the way of the passengers, make sure to hide these wires under the floor panels along the door. You may pop these panels up using the panel tools or simply tuck it under securely.

    You need to hide the wire as much as possible to avoid premature damage to it due to it being constantly stepped on and to avoid tripping the passengers. It’s also a good idea to use split looms to protect the wire from unnecessary pinching.

    Pro tip: Run the wire where there are already existing wires. You can be sure that this is a safe place. Clamp these wires together using a cable tie so that they’re not dangling everywhere.​

  15. Prepare the RCA and remote cables. Tape the remote wire to the RCA cable using the electric tape.
  16. Pro tip: You may just place the tape after every 12 inches or where you see fit.

  17. Pop the dash off. Using the panel removal tools, pop off the dash that covers the audio unit then place it carefully in a secure place.
  18. Pro tip: If putting the dash on the seat, use a blanket underneath it to protect your seat from unwanted scratches.

  19. Remove the radio. Using a nut driver or a screwdriver, remove the screws that hold the radio in place. Once all screws or nuts have been removed, pull the radio out.
  20. Pro tip: Do not use a drill at this moment because it may create an unnecessary hole.

  21. ​Hook up the RCA and remote cables. In front of the front passenger’s seat, there should be a removable panel that will expose a hole connected to where the radio was located.
  22. Feed the cables through the hole in front of the passenger’s seat to space where the radio was. Then using the knife of pliers, strip the ends of the remote wire and the remote turn on wire. The latter is the one already part of the factory wires installed.

    Next, using a crimper tool, attach the necessary connectors to each end then attach them to each other. Once done, hook up the RCA cable to the subwoofer output located at the back of the radio.

    After making sure all wires are securely connected, reinsert the radio into the dash. Screwing it in place and putting back the dash cover.

    Pro tip: Because this area may contain sharp edges, it’s a good thing to protect the RCA and remote cables with the split loom. Also, make sure the tuck the exposed RCA and remote cables under the carpet along the passenger’s side.​

  23. Place the amp. Depending on the class of amp you have, find the appropriate place for it. If it’s the Class D type, it’s ok to place it in places where there’s not much ventilation because it doesn't get too hot. For other types, find a place where air flow is good such as behind the back seat.
  24. You may use plywood or glass then attach it to where you plan to put the amp. Then drill and screw the amp in place.

    This is also the time when you tie the power, RCA, and remote cables together. Use the cable tie to do it then tuck them under the carpets.

    Pro tip: Use short screws to avoid penetrating the other side of where you are placing it, especially if you plan to place the amp in one of the side panels.​

  25. Connect the cables. Before placing all four screws of the amp, run the cables first behind it and plug them into their proper ports. For the power cable, remote wire, ground wire, and speaker wires, trim and strip off using the knife about 3/4” of the insulator at the edge. Once the inner wires are exposed, twist it about to avoid having loose wires.
  26. Once you have made sure not even a hurricane can dislodge these wires, you may place the rest of the amp screws in place.

    For the ground wire, you also have to attach it to the auto body or the back of the seat (depending on where you placed the amp). Use a star washer for better hold.

    Pro tip: Do not screw the amp in place too tight. It may damage the cables that run behind it. Also, use split looms for each wire for additional protection. And tie them using cable ties because you don’t want Tarzan’s jungle in your car.​

  27. ​Set up the subwoofer. Locate the other end of the speaker wires and again trim and strip off 3/4” of the insulator. Twist the exposed wires before inserting them into their proper places.
  28. Pro tip: If connecting two subwoofers to a single amp, go to the next section to know how to connect two subwoofers (or more).

  29. Tune the amp. We are almost done (thank goodness!). But before testing and tuning the amp, make sure the fuse is installed into the power cable. To do this, go back under the hood and attach the fuse to the power cable. Make sure the lid is snapped into place. Then, tune the amp as required.
  30. Pro tip: Using an oscilloscope will make the tuning easier.

  31. Finalize everything. Once you have tuned the amp and made sure the subwoofer is working properly, use a velcro or a strap to hold the latter in place. Afterward, put everything you have disassembled back into their proper locations. And dust off any dirt accumulated in the process.
  32. Lastly, check the electric system again to see if you have been professional enough not to damage anything.

    Pro tip: Allow a little bit of excess of an untucked speaker wire just in case you want to move it to a different, further place in the future.​

How to Connect Two Subwoofers

Connecting two subs to an amp that can handle multiple channels is pretty straightforward and easy. You just have to hook up the positive and negative terminals of the subwoofer to their respective terminals on the amplifier.

The trick comes in if you want to know how to bridge an amplifier, which is good if you want to increase the power output. It’s still not rocket science, but it involves some math when doing it.​

What you need

  • Multichannel amp
  • Subwoofers
  • Stereo wire
  • Knife or blade​

Here are the Steps

  1. Take note of the amp’s and subs’ specs. More specifically, you have to know the following:​
    • Bridged output power and power handling of the amp and sub respectively.
    • Impedance of both the amp and the sub.

    Basically, what you want to find out here is that the amp has enough juice to handle both your subwoofers. You may use calculators to find this one out.

  2. Connect the subs. Whether you have a single voice coil or dual voice coil, you have the option to increase or decrease the impedance depending on your wiring. Take note that the power needed to sustain the two subwoofers will vary depending on the wiring type you choose.
  3. Using the knife or blade, trim off 3/4” of the insulator on the speaker wires then attach them to the subwoofer terminals as needed.

  4. Wire the amplifier to the subs. Once you have finished connecting the two subwoofers, get another stereo wire and connect either the left or the right subwoofer to the respective negative and positive terminals of the amplifier.

Conclusion

Woohoo! You’re almost done with your very long day. I will not hold you for long but let me just remind you that this is just one way of setting up a subwoofer in a car. It will always depend, of course, on your devices and the type of car you have.

When in doubt, you can always leave it to the professionals.​

Erin Taylor
 

Chief editor of YouthTune, a music adventurer. I love learning about music and audio devices, which I eventually share with others so that they too can go on exploring the melodious world of music.

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