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Cone hole, can I refoam without replacing it?

JayPare

JayPare

Active Member
I picked up a pair of Atom V2 for 20$ CAD on monday and I thought it was a steal but after hooking them up I was really disappointed with their sound. I also heard some weird noise coming from them so I decided to open them, and surprise, they need refoam. I've done refoam in the past and for 20$ I don't really care having to do it, but one of the cone is in really bad shape. Here are my questions:
  1. Have you ever seen a cone broke in this manner? What might have cause this?
  2. Would you do a refoam on the one with the broken cone or it's only good for the trash can?
TIA
IMG_20201124_111355_7.jpg IMG_20201124_112557_5.jpg
 
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There are several good threads on here about cone repair. Most involve nothing more exotic than coffee filters and glue or other things you find around the home. I'd give it a shot, at worst you'll be $50.00 into the whole project.
 
mike j said:
Looks like a mouse entry point!
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That's the most probable answer I could think of. Never thought about it. Thank you.

nbarber said:
There are several good threads on here about cone repair. Most involve nothing more exotic than coffee filters and glue or other things you find around the home. I'd give it a shot, at worst you'll be $50.00 into the whole project.
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I'm a little concerned about adding to much weight to the cone as stated here. The missing weight due to the removed part of the cone is already affecting the woofer so I'm guessing it will be easy to add too much weight with coffee filters and glue, especially since I will need multiple layer to rebuild the whole hole to an acceptable stiffness. Do you have any suggestions of what I could use laying around the home?

@RTally I saw you were involved in a lot of speaker rework. Any time to chip in? :)
 
JayPare said:
@RTally I saw you were involved in a lot of speaker rework. Any time to chip in? :)
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I was hoping someone with more experience would speak up. :p

I've never had to repair damage where a part of the cone is missing. It looks repairable to me. If that were my speaker, this is what I would do:

It looks like the cone is a paper material. I would find some material of the same thickness, rigidity, and weight as the cone material. If you have another driver with similar cone material that is unusable, I would use the cone for a patch. You do not need much, so even buying a cheap clock-radio from a thrift and cannibalizing the speaker would work.

Make a patch the same size as the missing part of the cone. I would ensure the mating edge is rough, just like the edge of the missing cone section. I would then make a backing patch from a section of coffee filter slightly larger than the patch. The cone patch fits into the missing section and the filter paper patch goes on the back side of the cone to bridge between the patch and cone.

I would use Aileen's Tacky Glue to glue the edge of the patch to the cone and to glue the filter paper to the back of the cone. I would use wax paper on each side of the cone to squeeze the joint for a few minutes so the glue will set. This will ensure the cone patch is even with the rest of the cone. With the glue set, install a new foam. The foam will help hold the patch in place and provide most of the support for the patch.

I do not think that the weight of the repair would unduly affect the driver. The cone patch should not be adding weight because you are filling a hole. The only added weight will be the filter paper patch and a small amount of glue. That is not really much weight. The shape of the missing section is shallow relative to the edge of the cone, which is good.
 
rothwellaudio said:
How can you possibly conclude that when there's absolutely no surround left? :dunno:
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My conclusion was based on the fact that the damager woofer was outputting some clicking noise that the other one that only need refoam was not doing. Maybe it was only a coincidence.

RTally said:
I was hoping someone with more experience would speak up. :p

I've never had to repair damage where a part of the cone is missing. It looks repairable to me. If that were my speaker, this is what I would do:

It looks like the cone is a paper material. I would find some material of the same thickness, rigidity, and weight as the cone material. If you have another driver with similar cone material that is unusable, I would use the cone for a patch. You do not need much, so even buying a cheap clock-radio from a thrift and cannibalizing the speaker would work.

Make a patch the same size as the missing part of the cone. I would ensure the mating edge is rough, just like the edge of the missing cone section. I would then make a backing patch from a section of coffee filter slightly larger than the patch. The cone patch fits into the missing section and the filter paper patch goes on the back side of the cone to bridge between the patch and cone.

I would use Aileen's Tacky Glue to glue the edge of the patch to the cone and to glue the filter paper to the back of the cone. I would use wax paper on each side of the cone to squeeze the joint for a few minutes so the glue will set. This will ensure the cone patch is even with the rest of the cone. With the glue set, install a new foam. The foam will help hold the patch in place and provide most of the support for the patch.

I do not think that the weight of the repair would unduly affect the driver. The cone patch should not be adding weight because you are filling a hole. The only added weight will be the filter paper patch and a small amount of glue. That is not really much weight. The shape of the missing section is shallow relative to the edge of the cone, which is good.
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Thank you very much. The cone is in fact polypropylene but I will try to find something similar on a speaker in a thrift store and follow your advice. Will keep you guys posted.
 
JayPare said:
Thank you very much. The cone is in fact polypropylene but I will try to find something similar on a speaker in a thrift store and follow your advice. Will keep you guys posted.
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From the picture, the cone looks like it is made of a fibrous material such as you see with pulp-formed cones and not a solid polypropylene sheet, which generally cracks instead of tearing. If those are polymer fibers, you should use a glue that sticks well to the material. Aileen's may work, but I would experiment with different glues to ensure you use something that sticks well to the cone.
 
I'd expect compliance and symmetry would be more of an issue than weight. Accurate sound reproduction depends on the quality of the drivers producing it, and any repair other than a full re-foam by someone who's both skilled and meticulous MIGHT work, but you'd never know what you're missing.

(I'd also say that a RE-FOAM done by someone who's meticulous and accurate increases the chances of success.)

And as already noted, any possible degradation probably wouldn't be noticed by the average listener, but your dog might object ... ;-}
 
There's a Paradigm Atom woofer on Ebay (Texas) right now for $19.99+ shipping.

In my opinion trying to repair that cone is a fools errand (not calling you a fool, just using the figure of speech).
  1. it will never look right.
  2. risk of an unbalanced cone is high (that repair is at the outer edge where any imbalance is amplified the most being furthest away from the VC).
  3. a repair on the edge may be problematic getting a good joint with the surround.
  4. That clicking sound you describe may actually already be VC damage due to being run with failing surrounds and being unbalanced. You may never know if your refoam doesn't work whether it's your work, or if it was an already compromised driver.
  5. Even if a patch is successful, the cone will be compromised and any breakup will be unpredictable. Will it be audible? Who knows, but you may always wonder and never be confident the speaker is performing as it should.
If I were in your shoes I would look for another driver on the used market (try posting a wanted ad in Bartertown). Or, maybe call Paradigm and see if they sell re-cone kits?
 
dogwan said:
There's a Paradigm Atom woofer on Ebay (Texas) right now for $19.99+ shipping.

In my opinion trying to repair that cone is a fools errand (not calling you a fool, just using the figure of speech).
  1. it will never look right.
  2. risk of an unbalanced cone is high (that repair is at the outer edge where any imbalance is amplified the most being furthest away from the VC).
  3. a repair on the edge may be problematic getting a good joint with the surround.
  4. That clicking sound you describe may actually already be VC damage due to being run with failing surrounds and being unbalanced. You may never know if your refoam doesn't work whether it's your work, or if it was an already compromised driver.
  5. Even if a patch is successful, the cone will be compromised and any breakup will be unpredictable. Will it be audible? Who knows, but you may always wonder and never be confident the speaker is performing as it should.
If I were in your shoes I would look for another driver on the used market (try posting a wanted ad in Bartertown). Or, maybe call Paradigm and see if they sell re-cone kits?
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Thanks for the input. The woofer on Ebay is a little over what I was inclined to pay to get them back to work but I will keep this in mind.

I already send an email to Paradigm and waiting for an answer. I will also post to Bartertown to see if I'm lucky.

Thanks again!
 
JayPare said:
The woofer on Ebay is a little over what I was inclined to pay to get them back to work ....
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Don't get me wrong, I'm a total cheapskate and will often 'step over a dollar to pick up a dime' by investing hours upon hours of my time to solve a problem that could be easily solve by spending a reasonable amount. A mental exercise that helps me stay grounded is by comparing my hourly rate at work with the question at hand, and then deciding how many hours of overtime I would trade to have someone else solve the problem. In the case of the eBay woofer, after shipping it would be about 35-40 minutes of my time to stay late one evening to have the woofer delivered to my doorstep. No brainer for me. But, everyone has their own calculus and it's not for me to judge.
 
dogwan said:
Don't get me wrong, I'm a total cheapskate and will often 'step over a dollar to pick up a dime' by investing hours upon hours of my time to solve a problem that could be easily solve by spending a reasonable amount. A mental exercise that helps me stay grounded is by comparing my hourly rate at work with the question at hand, and then deciding how many hours of overtime I would trade to have someone else solve the problem. In the case of the eBay woofer, after shipping it would be about 35-40 minutes of my time to stay late one evening to have the woofer delivered to my doorstep. No brainer for me. But, everyone has their own calculus and it's not for me to judge.
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Yeah I think a little like that too but since I'm in Canada shipping was higher plus exchange rate sucks real bad so that's what made me hesitating. But I got it anyway. Hope this thread will help someone who isn't lucky like me and don't find a replacement woofer in the furure. Precious steps were given above.
 
I think a patch will be ok. The speakers cost you $20 and you probably don't want to throw a lot of money at these, and although a patch won't restore these to perfect condition I think they'll be acceptable - or at least they'd be acceptable to me.
 
I think you made a good choice @JayPare!
Patching a cone can be a real PITA sometimes and if you decide to sell them they made be hard to get rid of since the repair will be visible? By getting a replacement driver you may have saved time and money by attempting a repair on yours that may have a compromised voice coil. Keep us posted with an update.
 
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