A beginner friendly guide on how to fix a blown subwoofer 

When you realise that your subwoofer has blown shortly after you have purchased it,  it may feel like you got the short end of the stick! This is especially true for a brand new speaker that you just invested in and took the time and effort to set it up. Various factors may cause your speaker to blow and these can include inter alia too much volume or the amplifier clipping to underpowering.

Fortunately, a blown-up speaker does not render it obsolete! So, before you decide to dismantle or discard it, you might want to check whether your subwoofer can be fixed. Below is a simple guide on how to fix a subwoofer that beginners can follow.

How to Fix a Blown Subwoofer

Before you begin restoring your blown speaker, be sure to have the following tools at hand:

  • A screwdriver
  • Soldering iron
  • Air Compressor
  • Multimeter
  • Putty knife
  • Glue

Step 1- Assess the Voice Coil

Before you begin, you might want to examine every part of your subwoofer very carefully! You can start by checking the voice coil to see if it’s blown. The voice coil is a very important component that plays the role of amplifying the current running through the speaker. 

To assess the voice coil, you can use a very simple method which involves a multimeter. 

Step 1

Just connect the speaker terminals to the multimeter and see what happens. If the meter shows any resistance, it means the voice coil is still functioning; however, if there is no movement on the meter, then your coil is probably damaged. 

Step 2- Check the Speaker Cone

If it happens that the voice coil is still in good shape, you might want to move on to the next component, which is the speaker cone. The cone is usually built on a suspension system, so it will be easy for you to assess. 

Try pushing the cone gently along the sides, and do this across the circumference of the speaker. The cone is supposed to sink in and back into place. But if it remains rigid, this is a sure sign that your speaker cone is damaged.

Step 2- Check the Speaker Cone

Step 3- Detach the Speaker from its Frame

Depending on the results you obtained from assessing the voice coil and speaker cone, you’ll now have a good idea of where the problem is. From here it will be much easier to start the restoration process. The first thing you’ll need to do is to separate the speaker from its enclosure.

To do this you need to use the screwdriver from your repair kit. Unscrew the mounting screws that are holding the speaker in place. While doing this also remove all the attached wires but be sure to note where each wire is going for easy re-fit once you have repaired the speaker. 

Note that the wrong placement of the wires might cause the speaker to produce scratchy sound. Also, be sure to store the mounting screws in one place so that you don’t end up misplacing any.

Step 4- Remove the Speaker Surround

With the speaker completely separated from the frame and its wires detached, you will have to remove the surround from the speaker enclosure. To do this look for a sharp blade, such as a putty knife or tester edge to get through the glue that is binding the surround to the speaker frame.

Remove the surround gently,including all the glue from the frame. Be sure to be extra careful when doing this to avoid puncturing the edges of the frame as these are quite fragile. You don’t want to damage the speaker before you’ve even had a chance to fix it.

​Step 5- Remove the Voice Coil and Speaker Cone

The next order of business is to remove both the speaker cone and voice coil. For this, you will need a sharp object just like the putty knife or tester edge you used in the previous step. Remove the voice coil, as well as the speaker cone, slowly from the subwoofer. 

Remember to cut the terminal wires gently and carefully as you take out the coil, cone, and spider. Be sure to keep all other components separately in place.

​​Step 6- Replacing the Voice Coil

The voice coil is a very essential element in the subwoofer and that’s why it should be prioritized. This is where the actual fixing takes place and you’ll want to prepare a new coil to replace the old one. But before you do this, start by removing any dust particles, dirt, and other debris in the area of the voice coil gap. 

An air compressor should come in quite handy when cleaning the coil. Take the new voice coil and fix it inside the gap; place a fresh spider around it. Apply enough glue to the cone and carefully place it at the center of the new voice coil. 

Let the subwoofer stand for at least 24 hours so that the glue fully dries!

Step 7- Fix the Speaker Frame

Now that the new coil is in place, the next thing you’ll need to do is put back the speaker’s enclosure. To do this, carefully apply some glue around the edges of the surround that will be in contact with the speaker frame. Attach the surround to the edges of the cone and speaker frame.

Once again, you’ll have to allow another 24 hours for the glue to dry completely!

​Step 8- Reassemble and Fix Other Parts

The last step is to put all the other components in place so that the speaker is ready to work! Remember the wires we detached in step 3 must now be put back in place. 

Simply take the terminal wires on the new voice coil and attach them to where the old terminals were. Use the soldering iron to ensure that they are held in position. 

Try pushing the cone gently along the sides, and do this across the circumference of the speaker. The cone is supposed to sink in and back into place. But if it remains rigid, this is a sure sign that your speaker cone is damaged.

Step 8- Reassemble and Fix Other Parts

NB: If the new coil doesn’t come with pre-attached wires, try using smaller wires to connect to the terminal wires and punch some tiny holes into the new cone. Push the wires through the holes you’ve created to the coil while using your soldering iron to hold them in place. 

Finally, reattach all the other components separated earlier to their initial position. Fit your subwoofer into its enclosure and tighten it firmly together with the mounting screws. 

Connect your newly fixed subwoofer to the radio and enjoy the high-quality audio!

Conclusion

A subwoofer ensures that you have enough bass in your sound to balance the high-frequency tweeters. However, this will only be possible if it’s in good shape. If you have a blown subwoofer, don’t be keen to throw it away or replace it, it may still be salvageable!

The above guide should help restore your damaged subwoofer and turn it into a functional speaker. Just follow the steps mentioned above to get your subwoofer functioning again. It will save you the money you would have spent on taking it to a technician and it will also improve your DIY skills !!

GOOD LUCK!


Barry Allen

About the author:

Barry Allen

I grew up to be a self-proclaimed stuck-up audiophile, and I – partially – blame Pinnacle Speakers for it.


The whole point of me starting this website was to keep the tradition going. Although the means have changed, the mission remains the same: Bringing „sterling sound“ as they once put it into home theaters and sound systems worldwide! 


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