Picture of How to Repair a Cracked Speaker Cone.
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I got inspired to make this indestructible a couple of days ago when I stumbled across a set of really nice set of audiobahn subwoofers at a yard sale. The only problem was that the speaker cones were badly cracked from the previous owner pushing to many watts through them.  I bought them, took them home, and discovered a cool trick to fixing the cracks which you are about to learn about.

Don't blame me if you break your broken speaker cones lol.
This wont properly work on metal or plastic cones.
This fix will likely not make your speakers sound better than they did before they cracked. It should however sound better than they did when they were cracked.
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Step 1: Required Tools

Picture of Required Tools
Here is what you will need to fix your speaker.
Elmer's glue, gorilla glue (this stuff also works great for fixing cracks in speaker dust covers), or another type of semi flexible wood glue
A regular coffee filter.
A paint brush. I recommend a semi stiff bristled brush as it helps to rub the glue into the speaker cone
A plate
and last but not least a broken speaker...Duh

Step 2: Mixing the glue.

Your first step is to water down the glue so it will properly soak into the speaker cone.  Mix the glue with one part water to three parts glue. I wouldn't recommend adding any more water as it could cause the glue not to stick or make the speaker cone all soggy.

Step 3: Filling in and patching the crack.

Picture of Filling in and patching the crack.
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Start by filling in the crack with glue and letting it dry. Depending on how badly cracked your cone is it might take several applications. Remember to get both sides top and bottom of the cone filled with glue. Next take a piece of the coffee filter and cut it to size so that it covers about a quarter inch to a half inch on every side of the crack. Try and tear the coffee paper whenever possible instead of cutting it. This helps the fiber bond to the cone better and prevent the edges of the patch from peeling up over time. now use your paint brush and glue the patch on. Apply a relatively liberal amount of glue to the top and bottom of the patch patch as well as the cone it's self. Once your done it may be a good idea to go back around and put some more glue around the edges of the patch to keep it stuck down. You can now let the glue dry. Genially you sould only need one layer of the coffee filter patch but in high wattage applications like large subs I recommend adding a second layer of the patch for safety.

Step 4: Paint the patch (optional)

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The final step is to paint the patch. This is pretty straight forward. I don't recommend adding a thick coat of paint as it could weaken the glue and/or crack the paint from the speaker vibration.

Step 5: Your Done!!!

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That wasn't so hard now go try it your self if you haven't already. Leave a comment or question below about how it goes.

Gilly6 months ago

Thank you so much for this. One of our Mission speakers started buzzing and vibrating, especially on bass lines. It ruined all our music and my husband was looking at getting new speakers. Didn't really want to do that. Then he discovered that the speaker cone was loose half way round the edge. He looked online for help and found your instructable ( I did say to him where else would you get that kind of help :-) ). He used your white glue method and the speaker is good as new. Thank you - we are really happy to have our music back with no buzzing and vibrating!

kwfinley1 year ago

Paint can be brittle. Try a water based stain instead. Sinks right in.

xrobevansx3 years ago
Don't Elmers (AKA "school glue" or "white" glue) and Gorilla glue get pretty brittle when they dry? You think a more flexible when dry glue may be better suited for all the vibration it will encounter?
coolpizzadude (author)  xrobevansx3 years ago
Well elmers seems to work pretty well, I wouldn't recommend something like epoxy because that will crack. I also wouldn't recommend something super flexible like silicone sealant as it will damage the sound quality. Basically any semi flexible wood glue works well.
Ah...I see. Good! Just wondering.
hi & geat instructable - thanks !

Just foor for thought, but have you tried Plasti-Dip for the outside rubber cracked part of the speaker ???

i have two 8-inch tornado's and they both have had extensive repair work done with clear plastidip (can also be thinned)
there is copydex or other latex glues
whulbert3 years ago
hi i have a 12 in subwoofer with a crack less then 1 inch can any one help
rimar20003 years ago
Good work!

At step 3 photo 5 you say "There is no fix for this kind of crack...": I fixed a badly broken speaker's rubber suspension, using silicone sealant and an old light fabric strip. It does not look pretty, but it is operational.

coolpizzadude (author)  rimar20003 years ago
Cool! I figured that someone would probably call me on that :). I've tried it myself too. Yes it works but I don't think they sound the same when your done. Maybe I just did it wrong, I don't know.
Thanks for you support :)
Obviously, the solution is to change the cone, done by somebody that knows the trade. My work was over a relatively cheap speaker, without ambitions.