How to Convert a Home Subwoofer into a Car Audio Subwoofer

A subwoofer.
  • 5-10 hours
  • Advanced
  • 500-3,000
What You'll Need
A home subwoofer
A car stereo amplifier
Wire crimper tool
Wire strippers
Wire caps
Wire cutters
Speaker terminal block
Wood screws

If your car's stereo system needs more bass, you should consider adding a car audio subwoofer. You could go out and buy a new subwoofer to install in your car, but that requires that you spend a couple of hundred dollars on a quality unit. However, if you have an extra home subwoofer, you can convert it so that it can be used in your car. There are some modifications that will need to be made as there are some very basic differences between the designs of car and home subwoofers. Still, this step by step guide will show you what you need to do.

Step 1 - Choose an Amplifier

In most cases, your home-use subwoofer is an active subwoofer. This means that it probably has a built-in amplifier used to power the speaker. However, it is usually a 120-volt amplifier, and your car battery produces only 12 volts. You could purchase an inverted one, but those are a temporary solution at best. The good thing is that the amplifier used in most active subwoofers is not very good; therefore, a cheap car amplifier is more than adequate to replace it. Unless you want the bass to overpower the rest of the music in your car, choose a cheap amp that is rated about half (in terms of wattage output) of your main car amplifier.

Step 2 - Remove the Electronics from the Sub-Woofer

Remove the screws that hold the plug adapter assembly in place and remove the assembly. Snip off the wires that go to the speaker itself and discard the other electronics. Get rid of the power cord. This is only used for the amplifier so you won't be needing it anymore. If the assembly can't be removed, you will need to cut an opening in the box. Make sure that it is the same size as the speaker terminal block you will be installing.

Step 3 - Select Wiring Method

Take a peek inside the box at the speaker itself. You will need to determine how many voice coils the speaker has. Some woofers have only one and will have two wiring terminals. Other subwoofers have two voice coils and will have four tabs where wires are connected. It does not really matter, but it will help you determine how to wire the subwoofer to the amplifier.

Step 4 - Attach Amplifier to Subwoofer

Take some wood screws and attach the amplifier to the top of the subwoofer. This is optional but it helps to create a self-contained unit.

Step 5 - Wire the Subwoofer to the Amplifier

If the speaker has two wires only, you will need to connect the positive wire from the speaker to the positive terminal on one channel of the amplifier and the negative wire to the negative terminal to the other channel. This will leave the negative terminal on the first channel and the positive terminal on the second channel blank.

If the speaker has four wires, wire the amplifier the same way. Make sure the wires running from the amplifier are wired to the two outermost terminals on the speakers. Then make a small jumper wire and run it between the two middle terminals.

Step 6 - Install the Subwoofer

Your home subwoofer will now work like a charm in your car. Hook the amplifier up to the subwoofer channel on your car's stereo head unit and enjoy the bass.