How To Fix A Blown Subwoofer Like An Expert?
Oops! Speakers can get blown for various reasons (amplifier clipping, too much volume, too much time at high intensity). Disappointing as it is, low-quality speakers or a number of factors can lead to blown speakers. After spending so much time finding and putting a speaker in, you might feel cheated by its short life span.
To fix your blown subwoofer, you’ll need to take it out of your car, fix or replace any damaged parts, and glue/wire it back together. This process can range from easy to very difficult, depending on the problem. Here are a few steps to follow to fix a blown subwoofer:
- Check the Blown Subwoofer
- Detach the speakers
- Fix the Stuck Coil or Fix Any Tears
- Replace the foam surround
- Replace the Speaker Cone and Coil
- Reinstall the Speaker
Before making a decision to repair a blown subwoofer, figure out how damaged your speaker is, how long it should take to fix it, and if it’s easier or makes more sense to get a new one. Let’s find out if it makes sense for you to make an attempt to fix a blown subwoofer. The following information can help you decide.
Subwoofer Basics
Subwoofers can come in various diameters and depths. A subwoofer is designed to create better bass by reproducing the low-frequency sound of your music; in short, this is the element that adds the BOOM to music and helps you feel it.
For music lovers, the subwoofers aid in the music experience and create an entirely different atmosphere when it is played. Your subwoofers can normally be one of two types: Powered or Passive.
- Powered subwoofers operate using the car’s receiver for power. The stereo receiver can power some subwoofers just fine for good-quality sound.
- Passive subwoofers draw power from an external amplifier. These subwoofers need an external amplifier to produce sounds as if they were meant to be heard.
When the subwoofer draws power, it can get damaged if it is under or overpowered. Each subwoofer can handle a certain amount of power, but if the power is past the handling capacity of the cone, it could tear the cone, the suspension material (rubber/foam), and the spider.
Why Did My Subwoofer Get Blown?
The fact that the subwoofer gets damaged means the power is too great or too little. Usually, the subwoofer can handle what it is rated for, but better construction allows for more mistakes, meaning the speaker can last longer.
Overpowering a speaker can damage the voice coil, making it move too far, crashing it into the plate or yoke of the speaker. The voice coil tends to get separated from the spider and the cone and might damage the coil itself. It may no longer create sounds if it is torn. You might hear a buzzing sound when music is being played. That’s one indication that the subwoofer is blown.
Underpowering a speaker can damage the speaker by overheating it, tearing it from irregular signals, and jamming the voice coil, so it gets stuck. Check that your amplifier has plenty of power to give to the woofer so signals are clear. If you hear a distorted signal/sound, don’t turn it up.
An amplifier rated for your speakers’ RMS is best. Too little power or too much can cause damage.
Steps to Check the Blown Subwoofer
First, a couple of checks should be done to diagnose the actual problem of why the speaker is not working. Once I had a speaker that stopped working. The voice coil was jabbed. I ended up getting the voice coil back in place, and it worked again. This was a quick fix.
Blown subwoofers may have some tearing or voice coil issues. These are more difficult problems because of two reasons:
1. Blown Coil:
The voice coil is the component that has current running through it to help it pull and push against the speaker magnet. It moves the speaker cone up and down to produce sound.
If you are not sure the coil is damaged, 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. Damaged Speaker Cone:
If there are no issues with the coil, the next possibility could be a damaged speaker cone, which is usually easy to detect. Since the subwoofer is built on a suspension system, the cone is easy to move and tear at times. Look for the following signs to so if your speaker cone is damaged:
- Gently remove the cover for your subwoofer and check for the movement of the cone by gently pushing along the sides.
- If the cone is rigid and does not move, this could mean the voice coil is jammed or broken. Check carefully for small rips or holes. You might need lighting, but eventually, you’ll notice a rip in the cone or foam suspension.
If there is a tear in the subwoofer cone or foam, the next step will be deciding on whether to fix it.
A foam replacement should take about 30 minutes, and parts are readily available.
A cone replacement kit will take longer and cost, sometimes as much as the speaker. The Cone, spider, and voice coil will all need to be replaced if any of one them is broken. This might take about 2-3 hours if following clear instructions.
Another cheap option is to use materials found at home. This could work fine in some situations if you don’t mind some imperfections.
The following are steps you can follow to repair various problems with your speaker. Follow these steps for DIY speaker repair.
Steps to be Followed
1. Detaching the speakers:
Use a screwdriver to take the speakers from the place where it is mounted and take off the attached wires. After that, find a clean place to work that has plenty of lighting.
Your job at this point is to check the speaker and see what the problem is. Is the foam suspension damaged, the cone, or the voice coil?
You’ll need to order your parts. For the foam suspension and glue, try Amazon.com. For the speaker cone and coil, try simple speakers.
2. Learn About How to Fix Your Speaker:
How to Replace the Foam Surround?
How to Replace Everything: the Foam, Cone, Spider, and Coil?
How to Repair a Crack or Small Hole Using a Simple Procedure?
Tools and parts you might need: Don’t forget a screwdriver as well. If you are getting a kit, some items may be included.
|
Hobby Knife Set |
Speaker Repair Glue |
Rubbing Alcohol |
Masking Tape |
Elmer’s Glue |
Epoxy |
|---|---|---|---|---|---|
| |  | | | |
3. Simple Fixes: Stuck Coil and DIY Tear Repair
STUCK COIL
Press on the speaker cone gently and see it moves. If not, get a flashlight and take a look to see if the voice coil is out of place. If the voice coil is pushed up, but the wires are still good, you can try gently moving it back into position.
Try pushing the speaker up on both sides, but not too high, and allowing the coil to readjust itself. If you can do this without damaging anything, test the speaker before reinstalling it. It may work fine, or there may be some unseen damage that prevents the speaker from working.
TEAR REPAIR
One way to fix a tear is with glue and a paper towel. Not a perfect fix but an easy one. Take the paper towel and if it is two-ply, remove one layer. Rip the paper towel to fit the size of your tear. The paper towel should be wide enough to cover the rip but not overly wide.
Take Elmer’s glue and spread it over the paper towel patch to go over the rip. The glue should saturate the paper towel but not be runny. Apply the glued paper towel patch to the speaker, gently pressing and smoothing it into the speaker using a tool such as a non-serrated butter knife. Repeat this process for the back of the speaker.
Wait for it to dry, and then apply black matte spray paint if desired. This procedure can help the fiber of the torn speaker to lock together again with glue and a paper towel.
(Credit: These steps are taken from- this video)
4. Replace the foam surround:
Cut the foam if needed, and use a hobby knife the remove the gasket. Place the knife between the speaker frame and the gasket, and slide it to separate the gasket from the frame. Go all the way around so it can be removed in one piece and used again. Clean the glued area on the gasket by scraping it with a utility/hobby knife.
Use a hobby knife to carefully cut away the foam from the speaker. Use the knife to scrape the speaker frame and wear the foam sat so there are no more particles. Use rubbing alcohol on a paper towel and apply it to the area where the foam is attached to the speaker.
Wait a minute and rub the foam with a paper towel to remove some of the foam. Then use the hobby knife to carefully scrape off the remaining foam.
Then you can use the glue and new foam surround and apply glue to the inside lip of the foam. After applying, use your finger to spread the glue onto the lip, turn the foam over, and apply it to the speaker.
This takes pushing the foam with a finger carefully all the way around the cone until the foam seats on the cone well. The glue may take a minute to be ready. Wait 1 hour for the glue to dry.
Next, apply glue to the area where the gasket was seated on the frame, so you can press the outer lip of the foam onto it and get it ready to apply to the frame. Push the foam into the glue all the way around and wait a minute.
Then start to apply the foam to the frame and, at the same time, check to see if the cone is centered by pressing down gently on opposite sides and feeling if there is any rubbing of the voice coil. Center if needed and continue pushing the foam down until it sits firmly on the frame. Wait 1 hour for the glue to dry.
Now you’re ready to apply the gasket. Check where the holes in the speaker frame are and align the gasket to those holes. Apply glue to the top edge of the foam and then place the gasket on top of the glue. Press down on the gasket for a minute, turn the speaker over, and let it dry for an hour.
Replace the speaker in the car. (At each step after gluing, you can double-check to make sure everything glued correctly and was centered properly before going to the next step.)
(Credit: These steps are taken from- this video)
5. Replace the Speaker Cone and Coil:
Additional Tools that you may need to complete the job. If you’re getting a kit, some items may be included.
| Soldering Iron | Flash Light | Wire Cutters | Paint Brush | Black Rubberized Adhesive | Speaker Tester |
|---|---|---|---|---|---|
| | | | | | |
You’ll need to follow the same procedures to replace either the cone or coil because the cone is glued to the coil and spider. When replacing the speaker cone and coil, refer to step 4 and follow any procedures that may apply.
Make sure you order the correct parts. There are many steps to this process. Please refer to the video in step 2 for more information.
Cleaning
- Cut out the speaker cone by cutting along the foam surround and cutting around just above the dust cover close to the terminal wires. A hobby/X-acto knife is helpful when cutting and cleaning.
- Remove the cone and cut the spider around the outer edge and the lead wires. Note how tall the voice coils sit.
- Remove the voice coil and any debris (use a vacuum if debris gets into the gap or a business card with tape on it, sticky side out) and use masking tape to cover where the coil used to sit. This ensures that no debris gets into the area where the voice coil needs to move up and down.
- Clean the spider remnants off the frame using a knife, and remove the gasket as in step 4 so you can use it again. Clean off any other leftover material on the frame.
- Use a soldiering iron to remove wires and solder from the speaker basket terminals.
- Remove the masking tape and inspect the coil gap area with a flashlight. Clean if needed.
Installing New Parts
- Place the shim into the coil gap and position the new voice coil outside the shim so it lines up with the basket terminals. If the coil width of the new coil is taller, place the coil a bit higher than it was previously. Fold coil leads over shim to lock in place.
- Place two pin holes in the cone where the lead wire will go. Look at the previous cone for reference.
- Apply a bead of speaker glue to the speaker frame, where the outside area of the spider is used to sit. Set the spider in place around the coil, make sure the glue soaks into the outer rim of the spider, and use a flat, dull tool to press down on the glued area. Wait an hour.
- Place a bead of epoxy along the inside edge of the spider, where the spider and the voice coil former meet (the former is what the voice coil is wound around). Spread the epoxy evenly with the tip of the epoxy or a dull tool.
- Apply speaker glue to the inside edge of the frame, where the gasket sat.
- Put the cone into place, lining up the holes you made previously with the voice coil terminals. Press down on the cone carefully, spreading your fingers over the surface for even pressure, and move the cone back and forth slightly so it sits into the glue and epoxy.
- Place a bead of epoxy where the speaker cone and former coil meet. Press down on the area where the foam meets the glue with your dull tool or finger until it sits well.
- Place the lead-out wires from the voice coil flat against the cone going toward the pin holes you made. Cut the lead wires so about 1/4″ of them are showing.
- Remove the shim. Tin the lead out wires, solder the two lead wires, and thread the wires through the holes. Pull the wires, so they lie flat on the speaker with no slack.
- Place a polyvinyl treatment on the fabric surrounds if applicable. Apply a bead all around the surround and use a smaller paintbrush to smooth it out over the entire surface of the surround.
- Use black adhesive and apply it over the coil lead wires.
- Then place the cone dust cover on and hold it down a large enough object to apply steady weight to the dust cover. Place a bead of black adhesive around the edge of the dust cap where it meets the cone. Finish by placing adhesive over the lead wires. Let it dry for an hour. Then remove weight.
- Place the lead wires into the basket terminals leaving slack for the speaker to move up and down without any problems. Then solder the wires into the terminals. Cut off the excess wire.
- Use speaker glue and place a bead of glue all around the area where you will place the gasket. Apply the gasket to the glue pressing firmly down to seat it onto the frame well. Turn the speaker over and let it dry for an hour. Finished!
The last step would be to test the speaker after they’ve had some time to dry (24 hours) before you place them back in the car. You can use a signal generator or connect it to the car stereo. You’re ready to install them in the car if it works well.
(Credit: These steps are taken from- this video)
6. Reinstall the Speaker:
Connect the wires back up to the speaker. Use the screws that you took from the speaker when you removed it, and replace the speaker in its housing. Place the speaker cover back on.
Conclusion
While many steps are involved when fixing a speaker cone and voice coil, you can do it with a little patience. Sometimes the fix can be fairly easy, so decide if you want to spend the time fixing a speaker or have someone else do it.
Make sure it is worth it for the money you are paying and the time you’re putting in. If not, an easy option would be to get a new speaker. I hope you can find a good option for you and if you want to learn more about speaker reviews, try out these other articles.
