Hook up Car Subwoofers at Home (Easy Guide)

Using car subwoofers at home can be a great idea to add more bass to your home theatre system.

It may happen that you have sold out your car or upgraded the audio system and don’t want to scrap the old subwoofer away.

In such a situation you can add your car subwoofer to your home audio system, however, you will need to keep a few things in mind which we will discuss in this article.

Additionally, we will also discuss the steps to hooking up your car’s subwoofer to your home audio.

Key Takeaways

  • Subwoofers used in cars and homes do a similar job of reproducing bass notes by handling the lower frequencies of audio notes.
  • One of the most important factors is to match the impedance (measured in Ohms ‘Ω‘) of the car subwoofer with the Amp rating.
  • Most home audio systems are 8 Ohms whereas most car audio systems are 4 Ohms.
  • The size of most cars subwoofer may not be enough to cover a large room and hence you may need to install additional subwoofer units to the home audio system.

Are home and car subwoofers the same?

Home and car subwoofers are specialized unit that do the job of adding that boomy bass effect.

However, the difference typically lies in the way you hook them up considering their impedance, power, amplifier compatibility, proper connectivity, etc.

Let us understand the difference between the subwoofers and their specific requirements to match your home audio system.

Impedance (Electrical Resistance)

The main difference between the car and home subwoofer is the impedance which is basically a measure of electrical resistance.

Impedance or electrical resistance in an electric component is measured by Ohm (‘Ω‘).

Similarly in subwoofers, it refers to the resistance of the electrical audio signals sent from an amplifier or receiver.

Most home theatre subwoofers hold a rating of 8 Ohms which means they will draw less electrical power.

On the other hand, car subs are usually rated 2 Ohms to 4 Ohms and will draw more electrical power and can cause overheating issues.

Simply put, by using the correct Ohm load, you will get the proper rated power including the maximum volume possible. 

On the other hand, if you use less than the rated Ohm subwoofer load with one or more subwoofers and speakers, may not work as desired.

Power Requirements

A car audio system including the subwoofer is typically designed to run on a 12 volts DC current which is generated by the battery of a car.

On the other hand, home audio systems operate on a higher voltage AC power source which is typically around 110 volts.

It may not be safe to connect the car subwoofer for power directly to a home theater systems subout.

Hence, to convert your car’s subwoofer for home use you will need to arrange a power inverter.

power inverters

Power inverters enable you to control the power and are capable of converting power to 12 volts.

Make sure to add two plugs one for the woofer and the other for the wall outlet.

Amplifier Requirements

This is another important factor to consider i.e., the Amplifier’s rating and the impedance rating of your car’s subwoofer.

An amplifier with a rating of 8 Ohms in your home audio system will require two subwoofers of 4 Ohms connectivity for even power distribution.

In case you attempt to run a 4 Ohms subwoofer speaker with an 8 Ohms home stereo amplifier can lead to more power drawn by the subwoofer.

Due to this, it will put a lot of stress on the amplifier which can be higher than its power handling capacity.

It is always advised to match the impedance rating with the amplifier before installing them.

This will help you make any additional arrangements if needed and prevent your audio system from being damaged.

Additionally, you can multiply the number of subs by their RMS ratings to get the total RMS rating value.

For example: If you have two subwoofers of 250 RMS watts each, the total RMS rating will be 500 RMS watts (2 x 250 = 500).

In order to power the Subwoofers evenly, the amp you choose will have to be capable of powering at least 75% and up to 150% of the total RMS rating.

This will power the entire subwoofer system evenly and without causing impedance-related issues.

Finally, if your car subwoofer has its own amplifier you can simply connect the sub to the amp and then the car amp to the main amplifier of your home audio system.

Speaker Crossover

Most car subwoofers run on car amps that have a built-in low-pass crossover.

In some cases, you will need to hook up a subwoofer speaker crossover between the home stereo and the car sub.

It will separate or block the higher-frequency sounds from passing to the subwoofer which will ultimately deliver clear bass.

Coverage

Although, car subwoofers can add bass to your home audio system, however, it will not be that effective in a larger room.

You will either need to place it closer to the listening area or add another unit for better coverage in your room.

Bass Effects

Car subs are typically smaller in size compared to subs available for home theatre systems. Hence, you may not benefit from the greatest bass output alongside large speakers.

To overcome this, you will need to play the subwoofer at a louder volume or add multiple subwoofer units to your home audio system to get the best boom-bass effect.

Materials

Car subwoofers are categorized as outdoor units and hence the materials used to make most car subs are marginally different and more durable than the home subs.

Outdoor subwoofers including car subs are designed to sustain different weather conditions (esp. water resistant) to some extent and are rated accordingly.

Depending on their rating some subwoofers are designed to be water-resistant to waterproof, dust-resistant to dustproof, and can also sustain hot and humid environments.

However, most modern subwoofers designed for home audio systems also come with protection ratings (IP ratings) from different environmental conditions. But they can be expensive.

How to hook up a car subwoofer at home?

Assuming you have unmounted your car’s subwoofer and are looking for the best methods to add it to your home theater system.

You will need to consider a few factors listed above in this article before hooking up the sub at home.

Things you will need:

  • A car subwoofer and a car amp.
  • A suitable power inverter to convert the amount of power voltage required for the car subwoofer (12 volts).
  • Power cable (wire) and a couple of plugs.
  • Wire cutters or strippers.
  • RCA cables or required speaker wires.
  • A proper space to accommodate the car amp and subwoofer.

Step 1: Arrange the items for setup at the dedicated spot

It is important to dedicate the best spot to place your car’s subwoofer and amp.

You should ideally choose a space closer to your home theater system.

This will help minimize lengthy wiring to connect them together.

Additionally, consider the placement of the power inverter closer to the sound system.

Now, keep the tools and system required for the setup and proceed to the next step.

Step 2: Disconnect the audio system from power

Make sure to disconnect the home audio system from power or unplug it from the power outlet.

It will prevent you from electrocution while connecting or disconnecting the cables and electrical wires from the units.

Additionally, you may also disconnect other speakers and woofers from your existing stereo or home amp.

Step 3: Powering your Subwoofer

To convert the power suitable for the car subwoofer you will need to connect it to either a AC to DC converter or power inverter.

Make sure the power inverter or the AC to DC converter (Transformer) is capable of converting or providing a 12 volts output.

Here’s a quick diagram that shows how to connect the sub using a AC to DC Converter.

connecting subwoofer using AC to DC converter

If you are connecting the subs using an inverter the connectivity will remain more or less same, you just need to replace the AC to DC converter with an Inverter.

Step 4: Connecting the Car Subwoofer to the Car Amp

This particular step involves connecting the car sub and amp using speaker wires.

Typically, the speaker wires should be twelve or sixteen gauges, however, it also depends on the model and type of your car subwoofer.

If you are unsure about the same, simply check the specifications of the subwoofer manufacturer.

Now, to connect the wires you will need to strip the wires about ½ inches and then twist the exposed wire ends. 

Next, connect the red wires with red by twisting them together firmly and mask them with electrical tape.

Similarly, you should connect the dark wire with the dark and mask them properly.

Additionally, in most units, there are brackets available beneath the terminals to push the wires, hence connecting them accordingly.

Once your car sub is connected to its amp you will now need to connect the amps for following the next step.

Note: Since home electric connections has AC current supply, you will need an AC to DC converter also known as transformer to connect the amplifier to it and then the amplifier connects to the passive subwoofer.

Step 5: Connect the Car Subwoofer with the Home Amplifier

This step involves connecting the wires to the input terminals of the subwoofer followed by connecting them to the output terminals of the home amp.

Hence, to connect the car’s subwoofer to the home amp you will need to pair the red wires with red and white wires with white.

Step 6: Connect other Speakers to the Home Amplifier

It’s time to reconnect your existing speakers to your home sound system.

For a better surround sound output from your home sound system, if you have five speakers, the ideal placement of the speakers should be two speakers placed to the left, two to the right, and one at the center.

subwoofer placement

Similarly with additional speakers place two to the left and two to the right with the subwoofer to the center.

However, you can place them according to your preference for listening to music.

Next, using the RCA cables connect the speakers to the main amplifier of the home theater.

Note: Do not connect the home speakers to the car’s amp.

Final Thoughts

The most important factor is to match the specifications and requirements of your car’s sub with your home audio system.

Another tedious task is to power the car’s sub with the right amount of voltage using a power inverter.

The placement of the car subwoofer can be customized as per the available sources to connect them to the sound system and your preferred way of listening to music.

By adding your car’s subwoofer to your home audio system, you can enjoy your favorite music notes the way you do while driving.

Armed with a Diploma in electrical engineering and a remarkable 12 years of expertise, he excels in rejuvenating music systems, washing machines, dryers, and laundry-related appliances. Manish's profound insights and practical know-how establish him as a credible authority in appliance and music system repairs. Contact: manish.singh (at) subwooferblog.com. He's always ready to lend a helping hand!