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How to Bridge Two Subwoofers?

Are you looking for maximum sound quality and performance from your car audio system? You can create a powerful base that will look great with the rest of your sound system by bridging two subwoofers together.

Bridging is not only crucial for the output power but also for producing high-quality bass sounds, but how can you do it correctly? Let’s find out.

There are two main methods for bridging subwoofers:

  • Parallel wiring
  • Series wiring

Here’s how to bridge two subwoofers together using each method:

Parallel wiring:

#1. Connect the positive terminal of the first subwoofer to the positive terminal of the second subwoofer

#2. Connect the negative terminal of the first subwoofer to the negative terminal of the second subwoofer

Series wiring:

#1. Connect the positive terminal of the first subwoofer to the negative terminal of the second subwoofer

#2. Connect the negative terminal of the first subwoofer to the positive terminal of the second subwoofer

Tip: When connecting subs, especially those strong ones, use proper wires.

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In this article, I will detail the steps involved in bridging two subwoofers together in both parallel and series connections.

How to Bridge Subwoofers Together?

There are two main ways to bridge subs: parallel wiring and series wiring.

Each method has its benefits and drawbacks, and it is important to choose the right one for your specific setup.

Bridging Two Subwoofers in Parallel

Parallel wiring involves connecting the positive terminal of one subwoofer to the positive terminal of the second subwoofer and the negative terminal of one subwoofer to the negative terminal of the second subwoofer.

This is the most common way to bridge subwoofers, resulting in a heavier load and less resistance to the amplifier, allowing for more power to be extracted from it.

There are a few key benefits to parallel wiring:

  • Increased power: As mentioned, parallel wiring allows more power to be extracted from the amplifier, resulting in a louder and more powerful bass. However, this can only work if you have a strong amplifier capable of meeting such energy demand.
  • Easy to set up: Parallel wiring is simple and requires minimal additional equipment. All you need is some speaker wire and a way to connect it to the subwoofers and amplifier.
  • Works with most amplifiers: Most amplifiers are designed to handle a 2-ohm load, which is what two 4-ohm subwoofers become when wired in parallel. This means you can use most amplifiers with parallel-wired subwoofers without any issues.

To set up parallel wiring, follow these steps:

#1. Determine the Impedance of Your Subwoofers.

Most subwoofers are either 4-ohm or 2-ohm. Therefore, it is crucial to know the impedance of your subwoofers to wire them correctly.

#2. Gather Your Equipment

You will need speaker wire, wire strippers, and a way to connect the wire to the subwoofers and amplifier.

#3. Strip the Ends of the Speaker Wire

Use the wire strippers to remove about an inch of insulation from the ends of the wire.

#4. Connect the Positive Terminals.

Join the positive terminal of one subwoofer to the positive terminal of the other subwoofer using the speaker wire.

#5. Connect the Negative Terminals.

Join the negative terminal of one subwoofer to the negative terminal of the other subwoofer using the speaker wire.

#6. Connect to the Amplifier.

Use the speaker wire to connect the subwoofer pair’s positive terminal to the amplifier’s positive terminal and the subwoofer pair’s negative terminal to the amplifier’s negative terminal.

#7. Test the Connection.

Once everything is connected, turn on the amplifier and test the connection by playing some music with solid bass.

If everything is working correctly, you should hear a significant improvement in the bass output.

Remember that both SVC (Single Voice Coil) and DVC (Dual Voice Coil) subwoofers can be wired in parallel.

Wiring DVC subwoofers in parallel is slightly more complicated, as you have to wire each voice coil separately. However, the overall process is still the same as with SVC subwoofers.

Bridging Two Subwoofers in Series

Series wiring involves connecting the positive terminal of one subwoofer to the negative terminal of the second subwoofer and the negative terminal of one subwoofer to the positive terminal of the second subwoofer.

This method is less common than parallel wiring, resulting in higher resistance to the circuit and less power being extracted from the amplifier.

However, there are still some situations where series wiring may be preferred.

  • One reason to use series wiring is to increase the overall impedance of both subwoofers. 

For example, if you have two 2-ohm subwoofers and want to increase the load on the amplifier to 4 ohms, you can wire the subwoofers in series.

This can be useful if your amplifier cannot handle a 2-ohm load or if you want to reduce the amplifier’s power output for some reason.

  • Another reason to use series wiring is to increase the overall power handling of the subwoofer pair.

In a series connection, the total power handling of the pair is equal to the sum of the power handling of each subwoofer.

For example, if you have two subwoofers with a power handling of 500 watts each, the total power handling of the pair would be 1000 watts when wired in series.

This can be useful if you want to run your subwoofers at high power levels and need extra power handling capacity.

To set up series wiring, follow these steps:

#1. Determine the Impedance of Your Subwoofers.

As with parallel wiring, ensure the impedance of your subwoofers to wire them properly.

#2. Gather Your Equipment.

You will need speaker wire, wire strippers, and a way to connect the wire to the subwoofers and amplifier.

#3. Strip the Ends of the Speaker Wire.

Use the wire strippers to remove about an inch of insulation from the ends of the wire.

#4. Connect the Positive and Negative Terminals.

Connect the positive terminal of one subwoofer to the negative terminal of the second subwoofer and the negative terminal of one subwoofer to the positive terminal of the other subwoofer.

#5. Connect to the Amplifier.

Connect the positive terminal of the first subwoofer pair to the positive terminal of the amplifier and the negative terminal of the second subwoofer to the negative terminal of the amplifier.

Do not mix it unless you want to see some fireworks.

#6. Test the Connection.

Once everything is connected, turn on the amplifier and test the connection by playing some music with strong bass.

If everything is working correctly, you should hear a change in the bass output, although it may be less loud than with parallel wiring.

Like parallel wiring, both SVC and DVC subwoofers can be wired in series. 

Tips and Considerations

#1. Follow the Manufacturer’s Recommendations for Wiring

Always follow the manufacturer’s guide and diagrams for wiring your subwoofers and amplifier.

Each manufacturer may have slightly different recommendations, so it is important to consult the documentation that came with your equipment.

#2. Use an Appropriate Amp Wiring Kit

An amp wiring kit includes everything you need to properly wire your amplifier, including the necessary gauge of wire, fuses, and connectors.

Using a correct amp wiring kit will ensure that your amplifier is protected correctly and will perform at its best.

Although many kits are available, I recommend KnuKonceptz Kolossus wires for powering the car amp (link to Amazon).

#3. Make Sure All Connections Are Secure and Tight

It is crucial to ensure all connections are secure and tight, as loose connections can cause problems such as reduced power output, distorted sound, and even damage to the amplifier or subwoofers.

Be sure to tighten all connections firmly, but be careful not to overtighten and strip the threads.

Conclusion

As explained in the article, there are two main ways to bridge subwoofers: parallel wiring and series wiring.

Parallel wiring results in a heavier load and less resistance to the amplifier, allowing for more power, but it requires a stronger amplifier.

On the other hand, Series wiring results in higher resistance to the circuit and less power being demanded from the amplifier.

FAQ

Can I Bridge Subwoofers With Different Power Handling Ratings?

Like with impedance, it is generally not recommended to bridge subwoofers with significantly different power handling ratings.

Mixing subwoofers with different power handling ratings can reduce performance and damage the amplifier or subwoofers.

I recommend using subwoofers with similar power handling ratings.

Can I Bridge a DVC Subwoofer and an SVC Subwoofer?

It is generally not recommended to bridge a DVC (dual voice coil) subwoofer and an SVC (single voice coil) subwoofer.

Mixing a DVC subwoofer and an SVC subwoofer can also reduce performance and cause damage to the amplifier or subwoofers.

It is best to use subwoofers with the same type of voice coil.

How Should I Match the Amplifier With Two Subwoofers?

Let’s say you have two subwoofers with the following characteristics:

  • Impedance: 4 ohms each
  • Power handling: 500 watts each

You want to choose an amplifier that can deliver enough power to drive the subwoofers properly and can handle the load presented by the subwoofers.

You also want to use parallel wiring, which results in a heavier load and less resistance to the amplifier.

Based on these factors, you would need an amplifier that can deliver at least 1000 watts of power at a 2-ohm load.

You can find amplifiers with these specifications by looking at the documentation with the amplifier or by consulting the manufacturer.

Here is an example of an amplifier that would be suitable for this setup:

  • Power output: 1200 watts RMS at 2 ohms
  • Impedance capabilities: 2 ohms

This amplifier has a power output of 1200 watts RMS at a 2-ohm load, sufficient to drive the subwoofers properly.

It also has an impedance capability of 2 ohms, which is suitable for the load presented by the subwoofers when wired in parallel.