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How to Repair Car Subwoofer?

A car subwoofer is an essential component in many car audio systems. It is responsible for reproducing low-frequency sounds, such as bass, that regular speakers cannot produce.

Maintaining and repairing a subwoofer is critical to ensure that it continues to function properly and produce high-quality sound.

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To fix a car subwoofer, take it out of your car and check for any damage. This can include a stuck coil, tears in the cone or surround, or a damaged voice coil. If necessary, disassemble the subwoofer, replace damaged parts and reassemble it back together. Finally, check the power supply to the subwoofer to ensure it is within the recommended range.

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Tip: When your subwoofer is severely damaged, the repair may not be cost and time effective, but for minor issues, repairing it can bring its performance to the right level.

When you make a simple cone or surrounding repairs, you need to have good glue that will keep the parts repaired for a long time.

The good glues I can recommend are the Devcon 2-Ton Epoxy and the Gorilla Super Glue Gel (links to Amazon).

In this article, we will go over the steps and materials needed to repair a cone and also cover some common subwoofer problems and how to fix them.

How to Repair a Subwoofer Cone?

If you want to repair subwoofer cone, be prepared for a detailed and time-consuming task. The following steps will walk you through the process.

The tools and materials you will need for this repair include the following:

  • flathead screwdriver
  • Pick or Allen key
  • razor blade or putty knife
  • 9-volt battery (for testing purposes only)
  • speaker repair kit (with glue, hair dryer, lacquer thinner, alcohol, and a rag)
  • the damaged subwoofer

#1. In most cases, the first step in repairing a speaker cone is to remove the outer ring or the surrounding. To do this, use a hairdryer to heat up the adhesive holding the ring in place.

Once it’s warm, use a flathead screwdriver to gently pry it off. Be careful not to damage the cone or voice coil while doing this.

#2. The next step is to clean the area with lacquer thinner and alcohol to remove any dirt or debris. This will ensure that the glue adheres properly.

When it comes to the best glue for subwoofer repair, many experts recommend using epoxy or super glue.

Epoxy is a two-part adhesive that forms a strong bond and can withstand high temperatures. Super glue, on the other hand, is easy to use and dries quickly. Both options will work well for the subwoofer repair.

#3. Once the area is clean and dry, apply glue to the cone and press it back into place.

Use a hair dryer to heat the cone and glue, which will speed up the drying process.

Be sure to hold the cone in place until the glue is fully dry, which can take anywhere from a few minutes to an hour, depending on the type of glue you’re using.

#4. After the glue is dry, reassemble the subwoofer by carefully putting the outer ring back in place. Again, make sure to put enough glue and do not leave any gaps, as the vibrations can damage the surrounding.

How To Fix Other Common Subwoofer Problems

Repairing the connection between the cone and surrounding ring is common, but not only possible damage. Below I detail more issues you can face with the car subwoofers with their fixes:

How To Fix a Subwoofer That Is Rattling

Rattling can be caused by several things, such as a loose voice coil, a damaged cone, or a problem with the subwoofer box.

To fix this problem, the first thing you have to do is to identify the cause of the rattling. It is often a good idea to tap on different subwoofer parts and listen to where the rattling sound comes from.

#1. If the rattling comes from the voice coil, it may be loose and need to be replaced.

#2. If the cone is damaged, you’ll need to replace it.

#3. If the problem is with the subwoofer box, you may need to add more insulation or secure any loose parts.

A few years ago, I had this issue with one of my boxes, and the problem was the leaking air through the wires terminal. After sealing the terminal from inside the box, the rattling has gone.

How To Take Apart Subwoofer Box

Taking apart a passive subwoofer box can be tricky, but it is less complicated than an active subwoofer. In any case, you must be careful and not damage any attached wires or other components.

The first step is to unplug the subwoofer and remove it from the box.

Once the box is open, you’ll see all pieces inside, including wiring, ports, and other structural parts.

Be sure to note how everything is connected, as you’ll need to put it back together correctly.

If the box is rattling and you are sealing it, adding the insulation, and securing loose parts, do so carefully and make sure not to damage any of the internal components.

When reassembling the box, use the mounting screws and bolts to secure it back together, and make sure not to overtighten them.

How To Fix a Subwoofer With No Sound

If your subwoofer is not producing any sound, it could be due to blown voice coil or a problem with the amplifier.

A good way to test if the voice coil is blown is using a 9-volt battery to apply a small amount of power to the terminals.

If the coil is good, the cone should move in response to the power. If it doesn’t, you will most likely need a new voice coil.

If the coil is not the problem, the issue could be, for example, with the amplifier clipping. Make sure all connections are secure and check the amplifier for any blown fuses or other problems.

If you’re unsure what can cause the sub to be silent, consult a professional or the subwoofer’s manual for further troubleshooting. 

How To Fix a Subwoofer With a Hole In Cone

A small hole in the subwoofer cone can be caused by many things, such as a tear in the foam or a puncture from a sharp object.

To fix this, you’ll need to patch the hole. One way to do this is by using a glued paper towel patch or speaker repair kit. Then, apply the patch to the hole and allow it to dry.

Another way to fix a hole is by using a foam repair kit. These kits include a foam sealant that can be used to fill the gap and then shaped to match the contours of the cone.

Once the glue is dry, you can paint it to match the color of the cone. I recommend painting the cone for the subs that are visible. For the spare wheel or under-seat subwoofer, this is not needed.

Remember that if the hole is big enough, you may do better with replacing the cone rather than repairing it.

How To Fix Blown Voice Coil in Subwoofer

Before fixing a blown subwoofer, you need to diagnose the problem. Here are a few checks you can do:

#1. Check the Voice Coil

Connect the terminals of the coil to a multimeter, and if there is no resistance detected, it could be because the coil is damaged.

#2. Check the Speaker Cone

Inspect the speaker cone for any damage or deformations.

Once you have found the issue, it’s time to fix the blown subwoofer. The process of fixing a subwoofer can range from easy to difficult, depending on the problem.

Here are a few steps to follow:

#1. Detach the subwoofer from the car.

#2. Fix the Stuck Coil or Fix Any Tears: If the coil is stuck or there are tears in the cone or surround, you’ll need to replace the coil or cone/surround.

#3. Replace the foam surround: If the foam surround is damaged, you’ll need to replace it.

#4. Replace the Speaker Cone and Coil: If the speaker cone and coil are damaged, you’ll need to replace them.

#5. Reinstall the speaker: Once all the damaged parts have been replaced, reassemble the subwoofer and reinstall it in the car.

Remember, when repairing a subwoofer, you will need to purchase the necessary replacement parts, such as a new speaker cone, foam surround, or voice coil.

If the damage is too extensive to fix, you may need to replace the subwoofer.


Repairing a speaker cone can be simple if you have the right tools and materials. 

Remember to test your subwoofer before starting any repair to ensure it is not blown. And when it comes to fixing other common subwoofer problems, you need to identify the cause of the problem before attempting to fix it.

With proper maintenance and repair, you can keep your car’s subwoofers in top condition and enjoy excellent sound quality for a long time.


Can Subwoofers Be Repaired?

Subwoofers can be repaired in most cases. If the cone is damaged or the voice coil is blown, these can be repaired or replaced.

However, subwoofers can also not work due to bad wiring or faulty amplifier, and in those cases, you must also investigate the rest of your car audio system.

How Do I Know if My Subwoofer Is Blown?

There are a few ways to tell if a subwoofer is blown.

#1. One way is to visually inspect the cone for any damage, such as tears or holes.

#2. Another way is to use a 9-volt battery to apply a small amount of power to the terminals and see if the cone moves in response.

The subwoofer is likely blown if the cone doesn’t move or makes a popping or crackling sound.

How To Fix a Subwoofer That Is Rattling?

To fix a subwoofer that is rattling, you need to identify the cause of the rattling.

One way to do this is by tapping on different parts of the subwoofer and listening for where the rattling sound is coming from. For example, if the rattling comes from the subwoofer enclosure, it may be loose and need to be tightened.

If the cone is damaged, you’ll need to replace it. If the problem is with the subwoofer box, you may need to add more insulation or secure any loose parts.

How To Take Apart a Subwoofer Box?

To take apart a subwoofer box, first unplug the subwoofer and remove any screws or bolts holding the box together.

Once the box is open, you can repair it inside and when finished, make sure to put it back together correctly.