Adding a Subwoofer to a Factory Stereo: Step-by-Step Guide

Adding a subwoofer to a factory stereo can dramatically improve the sound quality of your music. You can experience deeper and richer bass tones that will add new life to your music. In addition, a subwoofer can also help to fill out the sound of your music, making it sound fuller and more immersive. If you’re looking to take your music listening experience to the next level, then adding a subwoofer to a factory stereo is a great way to do it.

How can you carry this out, though? Can you hook subs to a stock stereo? Luckily, you can. Adding a subwoofer to a factory stereo can allow you to get the benefits of both units without having to completely change the structure of your car’s audio system.

Through this guide, you can go through how to hook up subs to a stock radio in sufficient detail so that you can then try the process out on your own as long as you have the relevant skills and confidence to carry it out.

Gather the Materials

You should first gather all the tools and equipment that you will require to carry out the process. Take a look at these through the following list.

  • A basic toolbox containing screws, screwdrivers, wrenches, pliers, tape, knife, sockets and hammers
  • A subwoofer box to house the sub
  • An amplifier
  • RCA cables
  • Wiring materials
  • Line output converter
  • An inline fuse of at least 50 amps
  • Safety equipment such as gloves, glasses and/or a mask

Depending on your individual system and requirements, you might need some other materials as well, so use your discretion in this case or ask a professional to help you out. You can also use alternatives to some of the aforementioned tools as long as they suit the system well.

Situate the Subwoofer

The first step you will need to undertake is to situate the subwoofer accurately in your car. Make sure you find a good enough location inside your car for this as it is important to provide enough space to the unit.

You do not want the subwoofer to be too cramped up as this could easily cause it to overheat due to the presence of the amplifier. As long as you find a place that can air out the heat and provide enough breathing space, then your subwoofer will function well.

Make sure that you can also easily reach the subwoofer whenever you want to adjust, clean or repair it.

The wires and cables should also easily connect to different parts of the system so that there do not have to face any kind of strain as this could otherwise create problems by preventing the subwoofer from working properly.

Take Precautions

You must ensure that you take the necessary precautions before you begin the wiring and connecting process so that you can add the car subwoofer to a stock stereo. These precautions can help you ensure that no accidents or damages take place while you are carrying out the process.

These accidents can otherwise hurt the sound system, other components of the car as well as cause injuries to you through shocks and hazards.

You do not need to detach the entire battery but make sure that you remove the negative terminal connection from the battery. You can then place this negative terminal wire aside by ensuring that it does not come into too much contact with any other parts of the car or vehicle.

Before handling any wires or cables, make sure that you wear all the safety equipment so that you do not come into direct contact with the materials. If there is any moisture around the parts, make sure you let it dry up.

Adding a Subwoofer to a Factory Stereo

Run the Wires

You will now have to run all the wires through their relevant connections. Go through the details of each kind of wire below.

Power Wire

You will need to connect the power wire to the positive terminal of the battery after which you can place this beneath the carpet of your vehicle. You will then need to attach this power wire to a fuse holder by ensuring that the length is enough to reach it.

Ideally, you should keep the fuse as close to the battery as possible, as this can reduce the chances of a short circuit.

Ground Wire

You will also need to connect a ground wire near the power wire. This ground wire will connect to the base frame or chassis of the car to complete the loop and ensure that the functioning of the system takes place in a noise-free manner.

In case there is any paint on this base frame, you will need to remove it using sandpaper to enhance the grounding quality of the wire and the frame. You should also sand any other components involved during this process if they have any paint on them.

Speaker Wire

The speaker wires are the ones that will be present on the factory car stereo. You will need to connect these speaker wires to a line output converter at the correct terminals.

RCA Cables

The RCA cables are necessary to provide the relevant signal to the subwoofer. Make sure you connect them in the right terminals of the line output converter.

You will also need to connect a turn-on wire along with the RCA cables. Both of these should be placed in the opposite direction of the power wire to ensure quiet functioning.

Use a Converter

You will need a line output converter if you have a factory car stereo in your car. This is because the factory head unit generally tends to have speaker wires but does not have a preamp output that can convert them into RCA signals.

This converter can make it highly convenient for you to connect the factory radio to the amplifier and subwoofer.

Make sure you connect the speaker wires accurately to allow the conversion process to take place easily.


Once you manage to connect all the wires to all the relevant attachments, such as the main system, the base frame or the line output converter, make sure you tighten everything in place and confirm once again that all the connections are placed accurately.

Once you are confident enough, you can reconnect the negative terminal of the battery to test out the sound system. You will need to turn on the subwoofer as well as the amp for this, although you can turn the latter to its lowest setting.

Test It Out

The final thing to do here is to test out the entire system. You can start off at lower settings and check different volumes and channels to ensure that everything is working to your satisfaction.

At this stage, you can also adjust the settings of the system so that everything is at your desired level. You can also start playing your own music and enjoy the enhanced sound quality.

At all points of the process, you will need to ensure that you are keeping yourself as well as the other parts of the vehicle completely safe. Deal with the wires carefully and always start testing out the system at low settings before you gradually progress to higher settings.

Adding a Subwoofer to a Factory Stereo


Can I Put a Subwoofer in the Car Without an Amp?

Usually, a subwoofer along with an amp can enhance the overall quality of the sound from the factory radio. However, it is possible to put a subwoofer in the car without an amp, especially if you have a limited budget. You will, however, require some advanced skills to get through this process.

Can a Head Unit Power a Subwoofer?

You can simply attach the car subwoofer to the head unit of your car to produce good sound results as long as you situate the subwoofer in a good enough location inside your car. While using an amp here might be more effective, a head unit can work if it meets your requirements well enough.

Where Does the Remote Wire Go On a Factory Car Stereo?

You can connect the remote turn-on wire on a factory head unit to the wire that is present on the antenna of the radio or to the fuse holder of your car or vehicle. Make sure that you carry out this process carefully to avoid any kind of damage.

The remote wire should also be close to the RCA cables when you are using the line output converter and away from the power source. This will help ensure that the entire sound system functions well without the wires adding to the sound.

Is adding a subwoofer to factory amp worth it?

Many people enjoy upgrading the stereo system in their car. One popular upgrade is to add a subwoofer to a factory stereo. A subwoofer is a large speaker that produces low frequency sounds. These low frequencies can add a lot of depth and power to your music. Adding a subwoofer to a factory stereo can be a relatively easy process. The first step is to find out what kind of factory system you have. Once you know this, you can then purchase a subwoofer that is compatible with your system. Next, you will need to grab the speaker wire signal from your factory stereo and connect it to the car battery. Finally, you will need to connect the speaker wire signal to the rca input on the subwoofer. By following these simple steps, you can easily add a subwoofer to your factory stereo and enjoy an upgraded sound system in your car.

Most factory stereos are designed to provide a well-rounded listening experience, but they often fall short when it comes to bass. This is where a subwoofer comes in. A subwoofer is a type of speaker that specializes in reproducing low frequencies, giving your music a deeper, more powerful sound. In addition, a subwoofer can help to improve the overall sound quality of your stereo by providing a stronger foundation for the other speakers to work with. Although installing a subwoofer may seem like a daunting task, it’s actually quite simple. In most cases, all you need is a few basic tools and some basic knowledge of car audio. With a little bit of effort, you can dramatically improve the sound of your factory stereo.

Can a subwoofer make a huge difference?

Many car stereo systems come with subwoofers built in, but for those that don’t, adding a subwoofer can make a big difference in the quality of the sound. There are a few things to consider when adding a subwoofer to a factory stereo, such as how to control the subwoofer and where to place it in the car. Additionally, subwoofers require power, so be sure to have a good car battery and an appropriate converter on hand. Finally, subwoofers can be very loud, so be sure to take fire safety precautions when installing one. By following these tips, you can add a subwoofer to your factory stereo and enjoy better sound quality in your car.

Final Remarks – Subwoofer to a Factory Stereo

Through this detailed guide, you now know how to install a subwoofer to a factory stereo using only a few steps.

To sum up, you will first need to gather your tools, wear your safety equipment, disconnect the negative terminal of the battery, place your subwoofer in an ideal location, run the wires using a converter and then reattach everything and test the system out.

Make sure you always connect the wires to their correct spots. Deal with them carefully and prevent any moisture from coming into contact with any of the parts.

In case you are not too confident about carrying out this process on your own, it might be best for you to call a professional.

Last Updated on November 5, 2023 by Brian Beasley

Written by Danny Reid

Hey, I'm Danny, and I know how hard it can be to find the perfect audio gear. Need a new stereo, amp, speakers, or subs? Don't worry – my blog is here to help you cut through the noise! My mission is to give you the best reviews, so you can make the right decision for your audio needs. And if you ever get stuck thinking, "Where does this blue wire go?" don't worry – I've got tons of cool tips to help you out of any jam. So come along with me on this fun, sound-filled adventure, and let's find the perfect audio setup to make your tunes really sing!