Learn How to Tap into Rear Speakers for Subs [2024 Expert Tips]

Are you looking to enhance your car audio system by adding a powerful bass experience?

If so, you’ve come to the right place!

By redirecting the audio signal from your rear speakers to a subwoofer, you can achieve a deeper, more impactful bass response, transforming your car’s audio system into a concert-like environment on wheels.

how to tap into rear speakers for subs

In this comprehensive guide, we will walk you through the step-by-step process of tapping into your rear speakers to power a subwoofer, allowing you to unlock the full potential of your car’s audio setup.

Whether you’re a car audio enthusiast looking to upgrade your sound system or simply someone seeking to add an extra punch to their music, this article will provide you with the necessary knowledge and techniques to accomplish your goal.

Get ready to take your in-car audio experience to the next level as we delve into the world of tapping into rear speakers for subs.

Understanding Subwoofers and Rear Speakers: Unveiling the Basics

Understanding Rear Speakers

When you tap into rear speakers for subs, it can transform your car audio system and allow you to maximize your music’s full potential while on the road. Understanding the fundamental concepts and components lets you build a powerful, immersive sound setup that enhances your driving experience.

First, let’s clarify what subwoofers and rear speakers are. Subwoofers are specialized speakers that reproduce bass, which is actually low-frequency sound. These speakers are excellent at delivering deep, rumbling tones that give depth and impact to music and other audio content. On the other hand, rear speakers are the speakers found at the rear of the vehicle’s cabin, typically used for surround sound effects in-car audio systems.

To tap into the rear speakers for subs, you’ll need a crucial component: the Line Output Converter (LOC). The LOC serves as a device that changes high-level audio signals from the rear speakers into a low-level RCA output that can connect to a subwoofer amplifier. It guarantees compatibility and optimal performance between the rear speakers and the subwoofer, enabling seamless integration of the two components.

The placement and positioning of the subwoofer and rear speakers significantly affect the overall sound quality within a vehicle’s confined space. If you strategically position the subwoofer and rear speakers, considering factors such as car dimensions and acoustics, you can create a balanced and immersive audio experience for your drives.

Prioritizing Safety: Ensuring a Secure Installation Process

When it comes to tap into rear speakers for subs, make safety the top priority. Handle electrical equipment carefully to avoid accidents and ensure a smooth installation process. Before tackling the technical aspects, implement specific safety measures.

Always disconnect the car’s battery first to sidestep any electrical shocks. This action is vital to protect yourself and protect the audio system from damage. Additionally, study and fully comprehend the manufacturer’s instructions and guidelines. Abiding by these instructions reduces the chance of mishaps and guarantees a safe installation.

Before you start tapping into the rear speakers, it’s wise to study the noise regulations in your location. Understand the sound limits for car audio systems to evade any potential legal complications.

Choosing the Right Tools: The Key to Optimal Sound Quality


You need a specific set of tools and equipment to enhance your car’s audio system. Here is a detailed list of items you need for this project:

Wire cutter and stripper:

These tools are essential for cutting and stripping the wires to establish connections between the rear speakers and the subwoofers. Make sure to choose a reliable wire cutter and stripper for precise and clean cuts.


Use a multimeter to test the voltage and resistance levels in your car’s electrical system. This practice safeguards proper connections and wards off potential damage to your equipment.

Line output converter:

A-line output converter changes high-level speaker outputs from your car’s rear speakers into low-level RCA outputs suitable for connecting to the subwoofers. Always opt for a high-quality line output converter to guarantee a seamless, distortion-free audio signal transfer.

Amplifier and subwoofer:

These components are essential for boosting the audio signals and delivering deep bass. Make sure you select an amplifier and subwoofer that align with your audio preferences and your vehicle’s power capabilities to provide optimal sound quality.

Quality equipment plays a vital role in attaining the best sound experience in your car. Using substandard tools and components might lead to underwhelming audio performance and possible damage to your system. Always choose reliable and reputable brands to enjoy long-lasting, high-quality audio on the road.

The Process: Tapping into Rear Speakers for Subs

Tapping into Rear Speakers for Subs

Step 1: Prepare

First, disconnect your vehicle’s power source. This will ensure your safety during installation and help prevent accidental electrical mishaps.

Step 2: Ensure a Safe Workspace

Clear your workspace of any potential hazards. This includes removing sharp objects or obstacles that could obstruct your access to the rear speakers, ensuring a safer environment to work in.

Step 3: Find the Correct Wires for Rear Speakers

Refer to the wiring diagram specific to the make and model of your vehicle. Find the wires for the rear speakers. You’ll typically locate these near the stereo or behind the rear panels. It’s crucial to accurately identify each speaker’s positive and negative wires for correct integration.

Step 4: Install a Line Output Converter (LOC)

Install a Line Output Converter (LOC) to connect the subwoofer to your car’s audio system. The LOC turns the high-level speaker outputs into a low-level RCA signal, enabling easy connection to your subwoofer amplifier. Follow the manufacturer’s instructions carefully for a proper, secure, and reliable connection.

Step 5: Connect the Subwoofer to the System

Link the RCA cables from the LOC to the appropriate inputs on your subwoofer amplifier. Make sure to correctly connect the positive and negative leads to avoid phase issues that could impact sound quality.

Step 6: Reconnect Power and Test the System

After making the connections, reconnect your vehicle’s power source. Switch on your car’s stereo and play music to test the system. Listen carefully to confirm the subwoofer is generating the desired bass response.

Step 7: Make Adjustments for Optimal Performance

Fine-tune the system to achieve optimal performance. Adjust the subwoofer’s gain and crossover settings as necessary to balance the subwoofer with the rest of your audio system perfectly. This will ensure you have a seamless and immersive listening experience.

Troubleshooting Common Issues

Tapping into rear speakers for subs can encounter several common issues during installation. However, practical solutions and helpful tips can help you conquer these obstacles and ensure seamless integration of your subwoofers.

One of the most common issues encountered is improper signal connectivity. This happens when the connection between the subwoofer and the rear speakers isn’t correctly established, leading to distorted or weak bass output.

You must connect the wiring correctly and use the appropriate wire gauge to manage the power requirements of the subwoofers. Use high-quality connectors and follow correct wiring techniques to enhance signal transfer and reduce interference significantly.

Phase cancellation is another common issue. This issue manifests when the sound waves from the subwoofer and rear speakers don’t sync, causing cancellation and resulting in a loss of bass response.

You need to adjust the phase settings of the subwoofers and align them with the rear speakers to overcome phase cancellation. You can do this using a phase adjustment control on the subwoofer or through the audio system’s settings. Synchronize the phase to achieve a cohesive and powerful bass output.

Ground loop issues can also impact the performance of rear speakers and subs. Ground loops happen when the audio system has multiple grounding points, leading to unwanted hum or noise.

Use a ground loop isolator or implement correct grounding techniques to solve this. This will help eliminate interference and ensure clean and crisp audio reproduction.

Lastly, the amplifier or subwoofers might not match properly with the rear speakers, leading to compatibility issues. This can cause imbalanced sound output and potentially damage the audio components.

To prevent compatibility issues, carefully review the specifications of the subwoofers, rear speakers, and amplifiers. Make sure they match in terms of power handling, impedance, and frequency response.

Consult professional audio experts or refer to manufacturer guidelines to gain valuable insights and make the right equipment choices.

Fine-tuning Your Sound System

Balancing Speaker and Subwoofer Power:

You must match the power rating of your rear speakers and subwoofers to ensure a balanced sound. Power discrepancies could distort audio or damage speakers.

Check your equipment’s user manuals or specifications to determine appropriate power levels and make adjustments as necessary.

Then you need to Deploy a High-Pass Filter:

This tool channels suitable frequencies to your rear speakers and sends low frequencies to the subwoofers. By doing so, you keep bass frequencies from overwhelming your rear speakers, allowing them to focus on delivering mid and high-range sounds.

If you fine-tune the crossover points, you can create a seamless integration between the rear speakers and subwoofers, ensuring a harmonious audio blend.

You also need to Fine-tune the Equalizer:

You use the equalizer to control the sound output from your rear speakers and subwoofers. Play around with the settings to find a balanced audio response that you like.

You can amplify vocal clarity by enhancing mid-range frequencies, and you can increase your subwoofers’ impact without overpowering the rear speakers by adjusting the low end.

Lastly, you should Adjust and Test:

To perfectly harmonize your rear speakers and subwoofers, you’ll likely need to experiment. Regularly test your system with various music genres and audio sources to ensure seamless component interaction.

Even minor adjustments like repositioning speakers, modifying crossover points, or adapting equalizer settings can dramatically improve the overall balance and sound quality. Trust your ears to guide you to your perfect in-car audio experience.

Aftercare and Maintenance Tips

subwoofer in car

To ensure the longevity and optimal performance of your car’s audio system, maintain it diligently. Key to this process is regular system checks and proactive maintenance, which can help identify and resolve potential problems before they escalate.

Here are some valuable tips for effectively maintaining your audio system and tapping into rear speakers for subs.

Inspect and Clean Connections:  

Start the inspection and cleaning process by looking at all the connections between the subwoofer and rear speakers. Dirt, debris, and loose connections can degrade the audio quality. Securely fasten all connections and keep them free from any dirt or corrosion. If they need cleaning, use an appropriate electrical contact cleaner. This simple action can improve signal transmission significantly and prevent signal loss.

Check Power and Ground Connections:

Loose or faulty connections can disrupt the power supply intermittently and lead to performance issues. Connect the power wire firmly to the battery and ground the ground wire properly to the car’s chassis. Inspect the fuse for damage or wear, replacing it if necessary.

Speaker Placement:  

Consider the positioning of your rear speakers and subwoofer closely. Incorrect placement can reduce sound quality and overall performance.

Consider your vehicle’s interior acoustic characteristics and try different locations for the best audio experience. Aim for a balanced soundstage where the subwoofer integrates seamlessly with the rear speakers.

Control Bass Levels:

Remember to control bass levels when enjoying your subwoofer’s deep, resonant bass. Maintain a balanced audio output to prevent overpowering the rear speakers.

Adjust the bass levels using the controls on your audio system or amplifier to achieve a harmonious audio blend. Excessive bass can damage the rear speakers and ruin the overall sound quality.

Regular Auditory Checks:

Make it a habit to actively listen to your audio system for any irregularities or distortions. Notice sudden changes in bass response, rattling noises, or muffled audio.

These signs could mean problems with the subwoofer or rear speakers, such as blown-out cones and damaged voice coils. Consult a professional or user manuals to troubleshoot such issues promptly.

Frequently Asked Questions: How To Tap Into Rear Speakers For Subs

How to connect subwoofer to rear speakers without amp?

Gather the necessary equipment: You’ll need an LOC, RCA cables, speaker wire, wire cutters/strippers, electrical tape, and a screwdriver.

Locate the rear speaker wires: Identify the rear speaker wires in your vehicle’s wiring harness. These wires carry the audio signal from the head unit to the rear speakers.

Disconnect the speaker wires: Use wire cutters to carefully cut the rear speaker wires, ensuring you leave enough length to work with. Strip about half an inch of insulation from the ends of the cut wires.

Connect the LOC: Take the RCA cables and connect them to the corresponding color-coded inputs on the LOC. The LOC will have two sets of RCA inputs—one for the left rear speaker and one for the right rear speaker.

Connect the speaker wires to the LOC: Attach the stripped ends of the rear speaker wires to the corresponding terminals on the LOC. Ensure a secure connection by tightening any screws or using the provided connectors.

Ground the LOC: Locate a suitable grounding point near the LOC, typically a metal bolt or screw. Use a screwdriver to secure the ground wire of the LOC to this point.

Connect the subwoofer: Take the RCA cables connected to the LOC and plug them into the RCA input on the subwoofer. Then, connect the subwoofer to a power source, following the manufacturer’s instructions.

Test the setup: Turn on your audio system and play some music with prominent bass. Adjust the subwoofer settings to achieve the desired sound balance between the rear speakers and the subwoofer.

Are there any risks involved in tapping into rear speakers for a subwoofer?

Tapping into rear speakers for a subwoofer carries a few risks. If the connections are not made correctly, you may experience audio distortion or damage to your car’s audio system. It’s essential to ensure proper insulation, secure connections, and avoid cutting or damaging other wires.

Will tapping into rear speakers affect the warranty of my car?

Tapping into rear speakers for a subwoofer installation typically does not affect your car’s warranty. However, it’s always recommended to check your vehicle’s warranty terms or consult a professional if you have concerns.

Can I revert the modifications if I decide to remove the subwoofer?

Yes, the modifications made to tap into your car’s rear speakers for a subwoofer are reversible. If desired, you can disconnect the subwoofer, remove the connections, and reconnect the rear speakers to their original state.

What tools do I need to tap into my car’s rear speakers for a subwoofer?

To tap into your car’s rear speakers for a subwoofer, you will need the following tools:

  • Wire stripper
  • Crimping tool or soldering iron
  • Electrical tape or heat shrink tubing
  •  RCA cables
  • Line output converter (optional if your subwoofer requires RCA input)

Can you tap into the rear speakers for a subwoofer?

Yes, you can tap into your car’s rear speakers to connect a subwoofer. This allows you to enhance your car’s audio system by adding a subwoofer for improved bass performance.

How can I get more sound from my rear speakers?

To get more sound from your rear speakers, you can try the following:

Adjust the speaker settings: Check your car’s audio system settings for speaker balance and fade options. Increase the volume or adjust the balance more towards the rear speakers.

Amplify the signal: Consider using an amplifier to increase the power going to your rear speakers. This can help to boost their output and improve overall sound quality.

Upgrade the speakers: If your rear speakers are of low quality, replacing them with higher-quality speakers can significantly improve sound output and clarity.

Can I put a subwoofer in my car without an amp?

While it is technically possible to put a subwoofer in your car without an amplifier, it is not recommended. Subwoofers require sufficient power to produce deep bass frequencies, and an amplifier ensures that the subwoofer receives adequate power. An amplifier will provide better sound quality and prevent strain on your car’s audio system.


Integrating subwoofers with your rear speakers can significantly enhance your audio experience, bringing depth and richness to your sound that you might not have thought possible. It’s an undertaking that demands careful preparation, the right tools, and a step-by-step approach, but as we’ve demonstrated in this guide, it’s a task well within the reach of any dedicated audio enthusiast.

I hope you enjoyed this guide and that it provided you with all the information you needed; you can find many more valuable articles on our site, such as: What speakers fit my car and How to wire speakers with 4 terminals.

As always, if you have any questions or encounter any issues, feel free to leave a comment.

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