Deterioration of certain parts of a subwoofer is inevitable, whether it’s because of age or less than ideal circumstances. Many would choose to replace their old subwoofers with a new one, repairing it would be a much cheaper option.
A blown speaker (broken subwoofer) destroys the quality of the audio creating unpleasant sounds that go through the subwoofer. That’s why you should learn how to fix a blown subwoofer voice coil, a cone, a foam surround, a broken wire...
Fixing a subwoofer can be a daunting or even sometimes, disheartening mission to complete. However, with proper preparation and research, do it yourself subwoofer maintenance can be achieved. You’ll get to save a lot of money for a new unit or pay someone to do it. Once the project is succeeded, you’ll be rewarded with a rich and beautiful audio system once again.
To be able to repair a subwoofer, it’s important for users to:
- Have an understanding of a subwoofer’s inner workings and have an idea of how these compartments work together to produce sound.
- Once they have a basic understanding, they should study about some common issues and the reasons why they happened in the first place and how to fix that.
- Learn some tips and tricks on how to repair subwoofer’s components.
Components of a subwoofer
Unless you know your way around the device, you’ll never be able to fix it. Not only you have to learn and tell different parts of a subwoofer, you also have to know how they work together in order for you to fix it.
- Integrated unit
- Separate individual
Because subwoofers produce bass sound, they are generally larger than regular speakers in sound systems.
Usually, subwoofers handle a range of low frequency sound between 20Hz to 200Hz. From 100Hz, subwoofers begin to crossover where they begin to pass off some higher frequencies to other speakers in the system. So, smaller regular speakers will produce higher frequency range.
Basic understanding of a subwoofer
Before attempting to become a DIY sound engineer, you must have a basic foundational understanding of the subwoofer anatomy and how they work together.
- Cone edge: It’s attached to the driver basket’s top edge and the cone’s top. It’s made of polyester, foam or rubber. Some call it a cone surround.
- Spider: It’s attached to the bottom of the cone and the coil. It’s usually made of corrugated fabric which is dressed with a stiffening resin. You can find it as a round and flexible disk.
- Wire: It’s attached to the coil.
- Voice coil: It’s attached to the cone and the spider. It’s usually made from aluminium. There are two subwoofer wires to power it.
- Magnet: It’s fixed and attached to the driver basket.
- Cone: Some people call it a diaphragm. The cone can be made of metal, plastic or paper. It is a conical element you can find in the middle of the speaker. The cone is attached to the voice coil, the foam surround, and the spider.
Subwoofer problem identification
There is a variety of factors that cause damages to the speaker such as:
- Age: After some time of use, the foam surrounds will naturally rot away.
- Cold and heat fluctuation: Can destroy the plastic components.
- Mice can eat certain parts of the subwoofer.
Here are some symptoms of a blown (broken) subwoofer, their possible causes, and the solutions. To determine the cause of the problem, you might need a little detective work. Learning about subwoofer configuration will help you do that.
No sound & No apparent problem
- The wire might have been decayed or the connection is loose: Replace it with a new one or re-establish the connection.
- The fuse (inside the speaker housing) is blown: Replace it with a new one and make sure it has the same rating as the original.
No sound and the bronze coil is burnt
- The voice coil is burnt out: You have two choices: Send it back to the manufacturer to have them replaced or do it yourself at home.
The sound produced is quiet scratching, very little
- The spider is broken: Replace the speaker surround and the cone by a re-cone kit.
The sound is muffled or distorted
- There might be a hole in the speaker cone: The hold needs to be repaired. You can use some items available in the house or some specialized repair kit.
The subwoofer produces rattling or buzzing noise
- The cone might have been destroyed: You can choose to replace only the cone or the entire subwoofer.
How to repair subwoofer components
Since the repairs can be complex, especially for those who have never tried fixing mechanical unit before, it’s important to plan ahead. Below are some tips on how to prepare the tools and supplies needed for the restoration project.
Don’t be so quick to throw out your subwoofer if no sound coming out of it. First, analyse all the components to figure out what’s wrong.
Replace a decayed foam surround or cone edge
The cone edge will decay over time hence the need of replacement. It’s quite easy to repair a decay foam surround. There are foam surround repair kits available on the market and the installation is simple:
- To make sure the new edge can properly adhere to the driver basket or cone, remove the old one completely.
- When installing the new foam surround, avoid drips and weak spots to form by applying the specialized glue evenly with care.
- Once you’re done gluing all the components, apply another thin layer of glue all over the edges to smooth them.
Just like the foam surround, the wire can break inside over time. They can also be affected by extreme, consistent fluctuations in temperature. When repairing wire, you have two options:
- Replace only one particular broken part of the wire.
- Replace entire wire: This is highly recommended. If you find a breakage problem in one part, it can affect other parts too.
It’s very easy to fix if anything happens to the wire. If there is a faulty wire, it’ll take a few hours to fix it with proper instructions, tools, and supplies.
You will need a soldering kit to begin the repairs. In case you don’t have one, get yourself a flux; solder wick, and a soldering iron. Some lead-free solder and a tinsel lead spool will also come in handy. Apart from all the soldering materials mentioned above, you’ll also need needle-nose pliers and some wire snips.
In case you have to replace a wire that extends to the coil, remove the old one with a new one and solder it in place. When splicing the wire, make sure both metal wire ends are new and clean. Once you’ve finished the connecting part, use a wire connector electrical tape to secure the place.
Repair the coil
Like I said before, you have two options when it comes to repairing the coil, send it back to the manufacture or attempt to do it at home. If you want to try it at home, the first thing you need to do is purchase a voice coil repair kit.
When repairing the coil, you will need to take the speaker apart then put it back together.
- If you can locate the crack, use silicone adhesive to fix.
- Squeeze the silicone adhesive onto your finger then spread it over the crack gently.
- Overlap a quarter inch of silicone on the sides.
- Before putting the subwoofer back together, let the silicone dry thoroughly. Or else, as you play the subwoofer, the break will likely recur.
Repair the cone
There are two scenarios:
- The diaphragm is destroyed totally: Replace it with a new one.
- The cone only has small tears and minor holes: Use a special kit to repair. You can use alternating items that are more easily available such as water, school glue, and tissue paper.
If you have a paper cone, follow these steps below. If you have metal or plastic cones, you will need a repair kit or even send them back to the manufacturer for repair.
- Mix water with school glue until the mixture becomes viscous.
- Carefully cut the tissue into strips so you won’t tear them. Make sure the width of the strips is slightly larger than the tear or whole.
- Apply the soak strips evenly to the tear or hole. Before adding another layer, wait till it’s partially dry.
- Overlap 3 – 5 layers to the sides of the cone in a criss-cross manner when it’s partially dry and let it dry completely.
Other issues that can be solved at home
If you’re a DIY enthusiast, you can buy kits from a specialist store or online, or you can also use materials that are available at home to solve a number of other subwoofer problems:
- A re-cone kit: Repair a fractured spider or a destroyed cone.
- Plastic, fibreboard, or wood: Repair a broken subwoofer enclosure.