How to Hook up a Subwoofer in a Car? — A Step-by-Step Guide

how to hook up a subwoofer in a car

Hooking up a subwoofer in the car will greatly improve its bass response. A professional can do this but you can save money through DIY. But do keep in mind that you have to be careful in making the connections because you can end up spending more. Our experts did the testing and outlined how to hook up a subwoofer in a car.

Subwoofer Basics

Subwoofers boost low-range frequencies. They come in two types: active and passive subwoofers. You can install a subwoofer in your car so you can also enjoy the loud, low-frequency sounds. 

A subwoofer speaker is made of stronger and heavier materials than that of your car speakers. Because of this, they can withstand stronger air pressure inside, making them able to boost bass sounds better. Stock stereo or full-range speakers do not have a very strong housing as compared to a subwoofer enclosure. 

JBL BassPro Subwoofer under car seat

Tools and Materials

The following tools are needed in installing subwoofers into your audio system. 

But before you install subwoofers to your audio systems, you will have to decide which type of subwoofer to get. Passive subs need to be powered by an external amplifier. These speakers usually produce a lower bass output. 

Powered subwoofers, on the other hand, are usually used in a car sound system as it is not dependent on the power output of a separate amplifier. It already has a built-in amplifier that perfectly matches the speaker, hence producing the optimal sound quality. 

Though a powered sub already has a built-in amp, some still prefer to connect it to another amp for audio data transmission.

(If you are in search of a great sub-brand, you can check our detailed review of Velodyne Acoustics subwoofers here)

Steps to Hook Up a Car Subwoofer

Our engineers have summarized the following methods on how to hook up a subwoofer in a car. Though you can do it on your own, you will have to follow these steps carefully in order to be successful.

Step #1: Find an Ideal Spot for the Subwoofer

The location of a subwoofer, like other full-range speakers, is very important in its sound output. In a room, they are usually placed in corners in order to produce louder sounds. 

man in his car

For cars, the most common placement for most subwoofers is in the trunk. There are many advantages, as well as disadvantages of placing them in this location. Our experts have broken them down for you. 

First, placing it in the trunk will not create an eyesore as it is hidden in the back. Hence, passengers will be more comfortable since they have more legroom and space as the sub is already placed in the back. 

It is also safer to place it there in case thieves try to steal something from your car. Since the powered subwoofer is out of the way, thieves will not be able to steal it. Lastly, the physical safety of the sub is best in the trunk as it is free from any other sharp objects that can puncture the speaker box. 

However, the biggest disadvantage is that if you want to keep it secure from any damage, you should only use the trunk for soft items. This would mean that gym equipment or any other hard equipment should not be placed there as it may cause damage to the sub. 

car sound systems

Also, the subwoofer car audio installation is a bit more tedious if the sub is placed in the trunk as there is less space to work with. 

Another option for the location where you can install your own subwoofer is in the cabin. This location will give better speaker outputs and bass tones. However, since it is placed inside the cabin, thieves can easily spot it. 

With these advantages and disadvantages, your decision should be based on the capacity of the possible location to accommodate your subs. 

Step #2: Run the Cables

Once you have finalized where to put your sub, you can now start the next step.  Run the power wire from the battery to the external amp. The wiring will come from the engine compartment up into the firewall. 

Find the opening in the car’s firewall first. Find the metal wall under the hood of your car, the one closest to your windshield. The other side of the firewall is located inside the car. The easiest place for connection is behind the glove box compartment. 

Massive Audio SUMMOXL104 installed in the trunk of a car

Now, wire in the in-line fuse close to the battery. Strip off the end of the power wire at the end where the battery is located. The fuse holder should be close to the battery to ensure that you don’t hear engine noise boosted through your amplifier. This will also help prevent it from blowing up the amplifier. 

One thing you have to remember at this step is not to connect it to the battery first. This is so you will not be electrocuted while doing the setup. Make sure to tape the point of connection of the power wire to the fuse so you won’t get grounded. 

Afterwhich, run the remaining wire under the carpets. You have to make sure that you have enough wire since it has to run from the engine until the trunk of the car. Aside from the power cable, you also have to run the RCA cables from the subwoofer up to where the amplifier is. 

You have to make sure that all the wires are laid out correctly so the audio system will operate properly. Another good thing to remember is to leave a bit of an extra cable for each of the connections so you have enough room to hook everything together. 

Now once all the cables have been laid out, you can begin wiring the audio cables. Pull out the stock stereo from the console of your car. On its back, you will see red and white RCA inputs and outputs. 

Pasow 3 RCA Cable

If your stereo does not support this, you have to pull the connector cables and splice them into compatible rear speaker wires. Then, plug them to the speaker wire outputs. The best option is still to buy a new audio set with RCA cables. 

Lastly, connect a remote wire to the stereo output that is labeled “remote” or “amp”. This will connect the amplifier and the stereo and will activate the former once the latter is turned on. 

Step #3: Install the Subwoofer

Before doing anything on this step, make sure that your subwoofer is mounted inside a portable box with mounting brackets. The sealed box and brackets are usually made of particle board covered with a layer of dampening felt cloth in order to contain bass tones. This will then create a more tight and accurate bass. 

Many subs already have built-in enclosures and are already pre-mounted. In these cases, you do not have to worry about anything anymore, just place your sub in the trunk of your prospective location. 

Once you are done with installing the subwoofer, you can now finish wiring the amp. An amplifier wiring kit usually comes with the amp when you buy it from a store. Connect the power cable that connects from the battery and plug it to the amp’s jack labeled as “Power” or “Batt”. 

BOSS Audio Systems P80DVC 1000 Watt, 8 Inch, Dual 4 Ohm Voice Coil Car Subwoofer - under

Next, make a solid connection between the stereo and the amp. To do this, the remote wire connected to the “Remote” or “Amp” terminal from the stereo to the “Remote” or “amp” plug of the amplifier. Then, connect the RCA cables to the inputs of the amp. 

Connect the wires to the positive and negative speaker outputs of the amp to the corresponding outputs of the subwoofer. Don’t forget to connect one end of the ground wire to a nearby bolt that is connected to the body of the car.

Step #4: Connect Power Wires

The last step that our experts mention on how to hook up a subwoofer in a car is to connect the power wires. 

Look for the ring terminals in your car battery. Remember, the blue wire is the negative while the red wire with the later bare metal connector is the positive terminal. Unhook the positive terminal of your battery. Twist the power cable and connect it to this terminal. 

Then, place the connector back on its ring terminal, securing the cable between the battery and the connector. Our experts also suggest to crimp connectors and crimp ring terminals to ensure a good connection.

Skar Audio SDR-10 D4 terminals

Lastly, start the car. Turn on the stereo to test if you have made the right connections.

(For other related pages, we also have a simple guide on how to connect two subwoofers to a receiver properly

Tips and Reminders

For your safety, wear insulated gloves in order to prevent electrocution. Don’t forget to install a ground wire [1] too in order to prevent short circuits. 

If you are in doubt with the connections, ask for help from a professional. Remember, the professional fee is cheaper than having all components of your audio setup, including your rear and front speakers fixed. 

Why Add a Subwoofer in Your Car?

If you want to truly have the best listening experience using your car audio, then your stock audio player will not do it for you. This is because they are meant to reproduce all the ranges of sound frequencies. 

However, if you want to enjoy the booming, low-frequency, or bass tones, then adding a subwoofer can do it. The heart-thumping bass can be more felt if you have a smaller car. 

(If you are looking for a reliable sub brand, we listed impressive subwoofers from JL Audio here

FAQ

Can I hook up a subwoofer to my stock car stereo?

Yes, you can hook up a subwoofer to your stock car stereo. You just have to run the power wire from the battery to the external amplifier. Then connect it to the stereo. There should be wires connected from the amp to the sub and the front and rear speakers too. 

Which subwoofer is the best for cars?

The subwoofer that is best for cars is the Alpine Type R12 Subwoofer. It can produce loud and beastly bass sounds with a solid and rugged design. It has 1000 watts RMS power and has 2-ohm dual voice coils. 

Conclusion

Adding a subwoofer to your car’s audio system will truly elevate your listening experience. Through this, you can enjoy loud and thumping bass sounds. Our sound experts outlined the steps on how to hook up a subwoofer in a car which include finding the ideal spot, wiring the cables, installing the sub, and powering it up. 

For other subwoofer products, we also listed the following for you: 

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Writer

Willie Greer
Willie Greer
Willie Greer is the founder of The Product Analyst. A cinephile, he has made it a personal quest to achieve the awesomest home theater possible. He now shares what he has learned through the years on the site, and has enlisted the help of tech-savvy colleagues in providing more insight about today’s most sought-after gadgets.