Converting Passive Subwoofer Into Active Subwoofer (Guide)

Passive subwoofers need an external amplifier to make sound, but active subwoofer has their own built-in amplifiers and crossovers.

This difference means active subwoofers produce better sound quality and precise bass.

In this article, I will guide you to transform your regular subwoofer into a powerful active one.

Steps to Convert Passive Subwoofer to Active Subwoofer

Step 1: Gathering Necessary Components

amplifier powersupply and crossover circuit

Active Amplifier Module: An active Amplifier Module, often used in active speakers and subwoofers, is a specialized electronic component designed to amplify audio signals.

Power Supply: Provides the necessary power for your active amplifier module to function efficiently.

Crossover Circuit (if not included in the amplifier module): Essential for dividing the audio signal into different frequency ranges, ensuring accurate bass response.

Step 2: Preparing the Passive Subwoofer

detaching passive crossover circuit

Removing the Passive Crossover (if Present): Passive crossovers are unnecessary in active setups, removing them streamlines the wiring and improves efficiency. Just in case you are not aware of what passive crossover over does,  in simple words it is an electronic circuit that splits an audio signal into separate frequency bands, directing them to the appropriate speaker drivers. It’s “passive” because it operates without the need for an external power source. 

Checking the Speaker Connections: Ensure all speaker connections are secure and free from damage, guaranteeing optimal signal transmission.

Step 3: Wiring the Active Components

Connecting the Amplifier Module to the Subwoofer Driver

This step is crucial in transforming your passive subwoofer into an active powerhouse.

Start by identifying the input terminals on your subwoofer driver. They are typically labeled for clarity.

Match these terminals with the corresponding outputs on your active amplifier module.

Ensure a snug fit for each wire, guaranteeing a secure connection.

Also, use high-quality speaker wires, considering their gauge and insulation quality.

Proper wiring not only establishes a stable electrical connection but also prevents signal loss, allowing the amplifier to drive the subwoofer driver efficiently.

Wiring the Power Supply to the Amplifier

Next, focus on powering up your active setup.

Connect the power supply to the designated input on the amplifier module.

Take extra care to observe the correct polarity, aligning positive and negative terminals accurately.

A reversed connection can damage the components and compromise performance.

Secure these connections tightly, using appropriate connectors or soldering for a durable setup.

A stable power supply ensures your amplifier operates at its peak, translating to robust bass output and extended durability.

Installing the Crossover Circuit (if Necessary)

The crossover circuit acts as the maestro, directing the right frequencies to your subwoofer driver.

If your active amplifier module lacks an integrated crossover, installing an external one becomes essential.

Place the crossover circuit between the amplifier and the subwoofer driver.

The crossover frequency should align with your subwoofer driver’s specifications, ensuring it handles the frequencies it’s most comfortable and effective at.

Carefully connect the input and output terminals of the crossover circuit, double-checking for accuracy.

A well-calibrated crossover ensures your subwoofer focuses on reproducing the low frequencies, delivering a refined and distortion-free bass response.

With these meticulous wiring steps, you establish the backbone of your active subwoofer system.

From the amplifier to the subwoofer driver and the crossover circuit, every connection must be exact.

Here, careful attention to detail ensures that your subwoofer not only comes to life but also functions at its peak, giving you a satisfyingly immersive audio experience.

Step 4: Testing and Adjusting

Testing the Newly Converted Active Subwoofer: Power up your setup and play various audio tracks to test the performance. Listen for clarity, depth, and absence of distortion.

Adjusting the Amplifier Settings for Optimal Performance: Fine-tune the amplifier settings, including gain, crossover frequency, and phase, to achieve the desired sound quality. Experiment with different tracks and adjust settings accordingly until you achieve an optimal bass response.

Each connection and adjustment plays a crucial role in ensuring your newly converted active subwoofer delivers bass that’s not just heard but felt.

Troubleshooting Common Issues

No Sound Output

Issue: If your newly converted active subwoofer isn’t producing any sound, it can be frustrating and confusing.

Solution:

Check Power Supply: Ensure the power supply is functional and correctly connected to the amplifier.

Verify Amplifier Connections: Recheck the wiring between the amplifier module and the subwoofer driver, ensuring all connections are secure.

Inspect Input Sources: Confirm that the input sources (e.g., audio cables) are working and connected to the amplifier properly.

Amplifier Settings: Check the amplifier settings, including gain and volume controls, to make sure they are appropriately configured.

Distorted Sound

 Issue: Distorted sound can ruin the audio experience, indicating a problem with signal processing or power handling.

Solution:

Adjust Gain: Lower the gain settings on the amplifier to prevent overloading the subwoofer driver.

Check Cables: Ensure all cables, including those connecting the amplifier, crossover, and subwoofer driver, are of high quality and properly shielded.

Inspect Audio Source: Verify that the audio source (e.g., music player or home theater system) is not sending a distorted signal.

Inadequate Bass Response: 

Issue: If the bass output isn’t as expected, it might indicate incorrect crossover settings or mismatched components.

Solution:

Crossover Adjustment: Fine-tune the crossover frequency to match the specifications of your subwoofer driver, allowing it to handle the appropriate frequency range.

Amplifier Settings: Adjust the amplifier’s low-pass filter settings to ensure it complements the subwoofer’s capabilities.

Check Subwoofer Driver: Verify that the subwoofer driver is in good condition and hasn’t sustained damage during the conversion process.

Benefits of Having an Active Subwoofer in a Sound System

Precise Bass Control

Active subwoofers give you exact control over the low-frequency sounds, making your music, movies, and games sound even better.

Saves Space

Active subwoofers integrate the amplifier within their enclosure, eliminating the need for a separate external amplifier.

This design conserves space, ideal for smaller rooms or setups aiming to minimize equipment footprint.

By integrating components, it reduces clutter from extra cables and power cords, offering a cleaner, streamlined appearance.

This integrated approach simplifies setup, and maintenance, and offers an aesthetically pleasing solution, especially in space-constrained environments.

Save Money and Improve Performance

If you convert your regular subwoofer into an active one, you not only save money but also make your sound system perform much better.

To make this upgrade, you need an active amplifier module, a power supply, and a crossover circuit if your amplifier module doesn’t already have one.

This simple change can greatly enhance your audio setup.

Less Wiring Hassles

With fewer cables to manage, there’s a reduced risk of tangling, misconnections, and troubleshooting.

This not only streamlines installation but also makes system modifications or relocations easier.

A cleaner setup with minimal wires enhances aesthetics, reduces clutter, and decreases the chances of accidental unplugs or trips, ensuring a safer and more efficient audio environment.

Limitations of passive subwoofers

The biggest limitation of passive subs is that it requires a separate amplifier to produce sound. In other words, they depend on the power of the external amplifier.

That being said, here are some notable limitations of passive subwoofers:

Matching Challenges

When using a passive subwoofer, it’s essential to pair it with an amplifier that delivers the right amount of power.

If the amplifier is too weak, the subwoofer won’t reach its full potential, leading to lackluster bass response.

Conversely, an overly powerful amplifier can push the subwoofer beyond its limits, risking damage.

Additionally, the impedance of the subwoofer and amplifier must be compatible. Ensuring this match requires knowledge and research, and getting it wrong can compromise sound quality or even harm the equipment.

More Wiring

Unlike active subwoofers with built-in amplifiers, passive subwoofers require separate connections to an external amplifier.

This means extra cables running between the amplifier and the subwoofer.

These additional cables can lead to a cluttered setup, especially if not managed well.

They can become tangled, be tripped over, or even disconnected accidentally.

Properly routing and securing these cables can be time-consuming and may require additional accessories like cable ties or conduits to maintain a neat appearance.

Also Read: Active vs Passive Subwoofer (Difference Explained)

Final Thoughts

This process of converting a passive sub to an active sub while complex, offers numerous benefits, from precise bass control to space-saving designs and reduced wiring hassles.

However, it’s essential to approach this conversion with care, ensuring each step is executed meticulously.

Frequently Asked Questions

What kind of active crossover circuit should I use?

Choose a high-quality, adjustable crossover matching your subwoofer’s specs, like Butterworth or Linkwitz-Riley.

How do I remove the passive crossover?

Desolder or disconnect wires from the crossover carefully, noting connections for reassembly.

What are common mistakes to avoid when converting?

Avoid incorrect wiring, polarity mistakes, improper crossover settings, and low-quality components for optimal results.

Meet the maestro behind our subwoofer symphony - Hemant Sarkar. With 15+ years of experience in speaker and home appliance troubleshooting, Hemant's expertise shines through in every word he shares. For all things subwoofers and sound systems, you can trust his seasoned guidance. Contact Hemant at hemant (at) subwooferblog.com.