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How to Install a Powered Subwoofer to a Factory Stereo

Every now and then We get e-mails and comments from readers who like to add some bass to their car stereo system. One recent one asked, “How can I install a powered subwoofer to a factory stereo?”.

Powered subwoofers include all the elements of a bass system — subwoofer, amplifier, and enclosure — in one convenient package.

No matter what kind of music you love, or how softly or loudly you like to listen, adding bass will enhance your music and make everything sound more beautiful and full.

A powerful subwoofer can reveal layers of sound that typical coaxial car speakers are simply not equipped to handle. That said, adding a powered subwoofer to your factory stereo is a great way to improve your sound without giving up your familiar factory controls.

How to Install a Powered Subwoofer to a Factory Stereo

Before you get started, you need to decide on where you want to mount your subwoofer. Some powered subs are small enough to be mounted under the seats.

Bear in mind that the sub’s built-in amplifier generates heat, so adequate ventilation is important whether you mount it under the seat or in the trunk.

Additionally, most powered subs do not come with the necessary wiring, so be sure to purchase a wiring kit that includes the wiring and fuses you’ll need.

Step #1: Disconnect the battery

It goes without saying that you need to disconnect the negative battery terminal before any electrical work to protect you and your gear during installation.


Step #2: Run the power wire

Next, run the power cable from the battery to the powered subwoofer through the firewall that separates the engine compartment from the main cabin. Once you’re inside the cabin, tuck the power cable under trim panels or your carpet along one side of your car all the way into the area where you’re going to mount the subwoofer.

Some amp wiring kits come with the fuse assembly already put together. If that’s not the case with your kit, you’ll need to cut a short piece of the power cable, enough to cover the distance from the battery to the fuse holder location, and strip wire insulation off both ends as needed to crimp terminal rings to one end and to attach the fuse holder to the other end.

Afterwards, remove the insulation from the end of the wire that leads to your amp and attach it to the other end of your fuse holder. It’s highly recommended to mount the fuse as close to the battery as possible to prevent short circuits.


Step #3: Run the turn-on wire and signal cables

After running the power wire, the next thing to do is run the turn-on wire and signal cables. Since most factory stereos aren’t equipped with preamp outputs, you’ll need to use a line output converter (LOC for short).

What a line output converter does is that it converts speaker-level output signals (high-level amplified signals) into RCA preamp-level signals (low level signals); those that you can actually feed an amplifier with.

Otherwise, you can just tap into the speaker wires behind your stock stereo, or possibly the rear deck speakers to get signal to the powered sub’s built-in amp.

You don’t want to run these wires, the turn-on wire, and the RCA cable, right next to the power wire. That’s a great way to get noise introduced into your system. That said, run them down the opposite side of the car from the power wire.


Step #4: Connect the ground wire

The third primary connection is the ground wire. You want to ground your powered subwoofer to a good bolt that goes right into the vehicle’s chassis.

The ground wire terminal should be in contact with the vehicle’s bare metal. With that said, use some sandpaper to sand away any paint or primer at the contact or grounding point for the best possible grounding.


Step #5: Make your wiring connections

Last but not least, reconnect your vehicle’s negative battery terminal, but before firing your powered subwoofer up to test, make sure to turn the built-in amp’s gains all the way down. You’ll also need to verify that the subwoofer turns on when you start the car. Then you can play some music and set your gains.


Final Thoughts

Everybody knows that a good subwoofer will make a night and day difference in terms of sound quality by bringing out the best in any kind of music from classical to hip-hop. Powered subs are no exception. They are one of the easiest and most cost-effective options to fit your sound into tighter spots without much hassle.

We’ve reviewed a wide variety of powered subwoofers that’ll help you bring the boom to almost any vehicle. So, whether you’re looking for high power and a big woofer or a small unit that can easily fit into tight spots, you’ll find something that suits your style and your budget.

Alex Brown

Hey There, my name is Alex Brown, I'm a music lover and a car audio enthusiast. I've installed everything from navigation systems to full car stereo systems, remote starters, alarms and beyond. I've been in this industry for years now. I enjoy creating solutions and simplifying everyday needs. My passion for music came at an early age. I love helping people get great sounding gear, thereby, saving the world from bad sound one customer at a time.

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