Recone subwoofer or any speaker

Recone subwoofer or any speaker

[UPDATE] There is now a video version of this tutorial located here.

Sometimes you'll need to recone a speaker or subwoofer. Sometimes the coil burns out, the tinsel breaks or a screw driver goes through the cone ! There's a lot of reasons that your speakers damaged, but you rarely need to throw it away. By their very design, most speakers are easily reconed at home by anyone. If you can cut cardboard and use super glue, you can do this !

Tools:
- A Stanley knife or razor blade (to remove the old cone/coil)
- A metal scribe (very handy, you'll find ways to use it)
- A small flat screw drive
- Soldering iron & solder
- Bottle of Acetone (from hardware store)

Reconing parts:

Reconing kit parts

This is a complete recone kit from the manufacturer (Atomic Loud Speakers). The kit includes:
1x Coil, former & spider assembly
1x Cone & surround assembly
1x Dust cap
1x Lock Ring (not all kits include this, it secures the spider to the basket)

Loctite Prism 480 adhesive. Its specially designed for high pressure, high temperature bonding of rubbers, alloys & canvas, and dried without residue. Perfect for our application ! Fully cured, it will withstand 22PSI of strain.

Notes on selecting adhesives:
1. Dont use an epoxy, they can't be easily removed if you need to recone again.
2. Superglue, Crazy glue, etc. will leave a white residue on the black cone due to the curing accelerators they use. They can also attack foam surrounds, so be careful and test on the old surround first.
3. Silicon based adhesives dont have a high enough bond strength for speaker applications.

Finally there are the gap spacers (the white plastic C's), these center the coil in the motor while the adhesive sets. Without them, it's almost impossible to get a good clearance and you'd end up with binding (scraping).
These were supplied with the reconing kit, but you might not get them with yours. As an alternative, you can experiment with thick paper strips to get the gap right. The pole piece should be a snug fit inside the former when the sleeves are in place. Make them AFTER cleaning the basket and BEFORE applying adhesive.

 

Here's a close up of the coil:
Former, coil & spider assembly

This assembly is Duel voice coil, flat copper wire, on a 2.5" alloy former with Kevlar wrap.
Duel spiders, formed and sealed in the factory with tinsel leads between the spider layers.
This will result in a DVC 1ohm subwoofer, with duel hard spiders. This setup should be good for 3000W in an SPL application.

Proceedure:


First you'll need to remove the old cone, spider & coils. Cut the old surround off, then remove the cone, finally cut the spider off the basket.
Here's the motor & basket with everything removed, ready for cleaning up.
Moving parts removed

Soaking the old glue for 15 minutes, then giving a good scrub down with Acetone has the old glue and daggy bits removed. A good clean surface is essential for a good strong bond !
Old glue removed

Make sure all the Acetone is all removed. Rough the surface with 600 grit Wet&Dry sand paper, then wipe with a clean dry cloth.
Apply Prism 480 to the lower rim on the basket ready to bond the spiders.
Apply adhevsive to bottom lip

Place your spacers inside the former, then slowly slide the former (with spacers inside) over the pole piece. Its a snug fit to ensure a perfect gap, so be gentle ! You dont want to damage anything or dent the former.
Former with spacers inserted, spider glued down

Prism 480 is a fast setting glue, so the spider is already starting to bond to the basket as soon as it contacts ! Add another healthy dose of 480 over the top of the spider around the edge.
OPTIONAL: To fit the locking rings, punch guide holes in the spider using the scribe. Lay down the lock ring and screw everything down firmly.
Spiders & coil are DONE ! We're 1/3rd of the way there.
Snug the spider down flush, add extra adhesive and you're done


While the 480 is going off (drying) is a great time to solder on the tinsel leads. Simply de-solder the old tinsels from the lugs with your soldering iron & a de-solder bulb.
Then insert your new leads, hit it with a soldering iron and some solder. Easy.
Solder on the tinsel leads

The finished soldering job, nice and clean.
A clean soldering job

Next step is the cone. Leave the gap spacers in place ! As the cones glue dries it may pull the former off-center, so keep those spacers in there.
Dont worry, we'll remove them soon.
Simply slide the hole in the center of the cone over the former and snug it down against the spiders. When properly seated, the outer edge of the surround will sit flush against the upper lip of the basket. This step requires some gentle coaxing, its a VERY snug fit.
Once its in position, apply a generous amount of 480 to bond the cone to the former & spider.
Slide the cone into place and glue the cone to the former

Getting close to finished now ! Applying Prism 480 around the edge of the basket to stick down the surround. Apply an even layer, gently lower the surround onto the adhesive. To ensure a good bond, sit a book ontop to gently push the surrounds edge down onto the basket evenly.
Leave long enough for the glue to dry.
Glue the surround down

All done. Spider, former & cone are bonded and the adhesive set. The surround edge is bonded to the frame and everything aligned. NOW you can pullout the spacers from between the former & pole piece (finally).
Almost done, everythings in place

Put 480 around the edge of the dustcap, center it, stick it down and put a bead of 480 between the edge of the dust cap & the cone for a good strong bond. I then sat a jar of peanut butter on the cap to hold it down while the adhesive set.
Dust cap in place

TADA ! All done. Just like brand new again and ready to make noise.

Complete and ready to use

 

FAQ:

Q. Can I use other adhesives ?
A. Sure thing. Loctite has a huge range of speaker specific adhesives you can use, they even have an indepth speaker building article on their website [url=http://www.loctite.com]www.loctite.com[/url]
I used Loctite because its what I could get, other brands such as 3M can be used with success.

Q. My speaker manufacturer says I need special glues only they make, is that true ?
A. They simply liscence adhesive technology from companies like Loctite & 3M. They're speaker manufacturers, not chemical industry ! Some will void your warranty for using "other" glues, but they'll void it for DIY reconing anyway so dont stress.

Q. Is this hard to do ? I dont think I could do it.
A. This is very easy. Infact, this tutorial is my FIRST EVER RECONE ! Thats damned easy.

Q. Do I need the specific recone kit for my subs ?
A. YES. Dont mess around, get the correct recone kit for your specific speaker otherwise you're in for grief.

Q. What subs are those ?
A. Atomic Apocolypse 10". 1ohm copper DVC, double hard spiders. They're built for SPL.

Q. Where do you get the recone kit ?
A. From the manufacturer, importer or speaker repair shop.

Q. Where did you get the Prism 480 ?
A. I call Loctites head office on their 1800 number and ask for your nearest distributor.