How to Bridge a Subwoofer

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Updated December 5, 2022

If you’ve invested in premium speakers, you may wonder how to bridge subwoofers for the best sound quality. Top-tier subwoofers provide a new audio channel and more detailed audio output at lower frequencies. That said, making a bride connection for speakers and subwoofers can seem complicated. While speaker wires can be confusing, you can learn how to bridge a subwoofer with this guide.

KEY TAKEAWAYS:

  • Ensure your amplifier offers a bridged mode for subwoofers and other speakers.
  • Connect your first subwoofer’s positive wire to the amplifier’s positive bridge terminal.
  • Wire the subs together, and connect the negative speaker wire to the negative output terminal to complete the setup.

Learning how to connect a subwoofer to an amplifier is usually straightforward, especially if you’re familiar with common wiring setups. That said, using a bridgeable amplifier can help you learn how to make a subwoofer louder through multiple amplifier channels.

Insider Tip

Your audio amplifier needs to push enough power to overcome the minimum impedance of your subwoofer and other speakers.

How to Bridge Subwoofers

Using a bridged amplifier with a single subwoofer ensures more power output through two separate channels. This leads to a powerful mono signal for bass across multiple bridged amplifier channels. That said, you should learn how to break in a subwoofer for the longevity and audio quality of the system.

Additionally, ensure you’ve studied some wiring diagrams before breaking out your amp wiring kit. While diagrams can give you a general blueprint, they might not match the exact setup of your audio subwoofer system.

STEP 1 Set Your Amplifier to Bridge Mode

You should find a switch on the back of your amplifier that activates bridge mode. It is near the positive and negative terminals on most amplifier models. These are the bridge terminals that will accept your wire speakers.

STEP 2 Connect the Positive Terminals

If you’re using two subwoofers, take the first one and wire the subwoofer’s positive bridge terminal to the amplifier’s positive terminal. Ensure that you’re using a thick enough wire to support the power output from your amplifier.

STEP 3 Connect the Subwoofers

Connect the negative terminal of the first subwoofer to the positive terminal on the second subwoofer. You can run the subwoofers in parallel by connecting two wires between the subwoofers.

STEP 4 Connect the Negative Terminals

Complete the circuit by connecting the subwoofer’s negative bridge terminal to the negative terminal on the amplifier.

Warning

You can blow out your speakers and subwoofer if you use an amplifier that exceeds the maximum power output they support.

STAT: A 2019 Noise Health survey found that men preferred an average 76-decibel listening volume regardless of their headphone type. (source)

How to Bridge Subwoofers FAQs

What is a safe listening volume?

The Hearing Health Foundation states that sounds at or below 70 decibels (normal conversation volume) are generally safe for human hearing. Anything over 85 decibels will likely damage your hearing over time, especially if the source of the noise is close by. Keep in mind that each 10-decibel increase is a tenfold increase in sound wave energy.

How do I clean my speakers?

You can clean your speakers with a dusting wand and a slightly damp microfiber cloth. Do not spray cleaning solution on the woofer driver, channel inputs, or power connections to prevent speaker damage. Experts recommend a vacuum or lint roller to remove dust from any fabric covering the speakers.

What is an acceptable speaker impedance?

Speaker impedance values are the resistance a speaker has to the electrical current from your amplifier. Manufacturers produce 2-ohm, 4-ohm, or 8-ohm impedance speakers, and your amplifier needs to provide enough power to overcome the impedance load. So, the correct minimum impedance depends on how much output power your amplifier provides.
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