If the coil is open circuit it is possible to dismantle the speaker... NOTE: If there is any sign of rubbing don't waste your time - go straight to a recone or replacement.
The following will get you right inside a driver - I have successfully done this on about half a dozen drivers. Please note though, it is a huge amount of work requiring a lot of patience, and I only invest the time and stress when I am dealing with a very old and/or irreplacable driver. I wouldn't waste my time on a modern driver or do this to a driver I intended to "give a hiding to" once back in service.
It is possible to unglue the surround and spider, allowing you to remove the cone and voice coil assembly. I have used toluene for this, though it will depend somewhat on the glue used on your driver.
You need:
1. A lot of patience, as you need to dissolve and lift the surround and spider very carefully, it is a slow process if you are to avoid cutting / tearing them.
2. A lot of guts, as you need to get a blase in and slide the glue joint as it dissolves.
You then need to cut out the dust cap, as you need to have access to the voice coil gap to align the driver when you reassemble it. This is the normal alignment process you use when reconing a driver.
Once you have the driver apart, you can
1) inspect and see exactly the issue and cause of open circuit.
2) If the failure is contained to the lead in wire, you can jumper over this.
Only start down this track if you need to - it is radical surgery on the speaker; also
Only start down this track if you enjoy fiddly stuff with speakers, as for the time you will spend you might be better served buying a new one.
The following will get you right inside a driver - I have successfully done this on about half a dozen drivers. Please note though, it is a huge amount of work requiring a lot of patience, and I only invest the time and stress when I am dealing with a very old and/or irreplacable driver. I wouldn't waste my time on a modern driver or do this to a driver I intended to "give a hiding to" once back in service.
It is possible to unglue the surround and spider, allowing you to remove the cone and voice coil assembly. I have used toluene for this, though it will depend somewhat on the glue used on your driver.
You need:
1. A lot of patience, as you need to dissolve and lift the surround and spider very carefully, it is a slow process if you are to avoid cutting / tearing them.
2. A lot of guts, as you need to get a blase in and slide the glue joint as it dissolves.
You then need to cut out the dust cap, as you need to have access to the voice coil gap to align the driver when you reassemble it. This is the normal alignment process you use when reconing a driver.
Once you have the driver apart, you can
1) inspect and see exactly the issue and cause of open circuit.
2) If the failure is contained to the lead in wire, you can jumper over this.
Only start down this track if you need to - it is radical surgery on the speaker; also
Only start down this track if you enjoy fiddly stuff with speakers, as for the time you will spend you might be better served buying a new one.
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This procedure to secure the butts on the spider is not original of any manufacturer, someone has made that spawn of hitting them, probably in a previous repair, imagining that they would be firmer, but severely limiting their flexibility.
If you are a recognized brand speaker, a complete replacement kit is a must. If it is not, I would throw it in the garbage basket.
If you are a recognized brand speaker, a complete replacement kit is a must. If it is not, I would throw it in the garbage basket.
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The best but already banned in some countries by the use as "cheap" drug by some
people fallen in disgrace, was the MEK (methyl ethyl ketone)
It has been replaced successfully by other solvents I have been told, but I do not more repair speakers, as you say, it is a job that most of the time does not compensate for the time invested..... ($$$)
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It is not acetone to dry, it is methyl ethyl ketone, it must be applied with a brush repeatedly and there is no adhesive to resist, (of those used in the speakers, of course) but the advantage against toluene is that it attacks some adhesives and / or materials of the cones and envelopes. (the foam destroys it, the MEK does not) In addition, toluene has greater residual power and takes longer to evaporate.
I was looking a little more closely at the OP photograph. Wow, I have to admit that maybe what I called spawn (the butts stuck to the spider) is something normal in a double coil subwoofer ... I never really had one in my hands ... could you clarify the point ?
By the way, the vintage white cones of JBL (I think of a compound they called Acuaplast or something like that) were falling apart with any solvent when trying to replace the wings .....
Well, I hope I can clarify my doubt without your answer, thanks anyway
Can someone contribute?
Dayton Audio UM18-22 18" Ultimax DVC Subwoofer 2 ohms Per Coil
Un Dayton Ultimax UM18-22
Here they have it, it seems that a few learn together here, but nobody wants to show their limitations .....
Anyway, move the mouse through the image and see a stitching of the butts, it seems that it is a technique used by some manufacturers and / or models of DVC subwoofers
Do not thank me, I know that heaven is waiting for me, with that I have enough.
Un Dayton Ultimax UM18-22
Here they have it, it seems that a few learn together here, but nobody wants to show their limitations .....
Anyway, move the mouse through the image and see a stitching of the butts, it seems that it is a technique used by some manufacturers and / or models of DVC subwoofers
Do not thank me, I know that heaven is waiting for me, with that I have enough.
MEK is good stuff for softening adhesives. I have used it to desolve adhesive in taking apart transformers. Avoid skin contact with acetone.
Avoid vapors; the MEK vapors smell like bad tequila
, toluene is carcinogenic so make sure you have very good ventilation if you use it, and avoid contact with skin. Also it is VERY flammable. 
Avoid vapors; the MEK vapors smell like bad tequila
, toluene is carcinogenic so make sure you have very good ventilation if you use it, and avoid contact with skin. Also it is VERY flammable. - Status
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