Instructables

Replace dry rotted speaker surrounds with cloth replacements.

Picture of Replace dry rotted speaker surrounds with cloth replacements.
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If you're like me, I can't pass up a nice pair of speakers sitting in the side of the road. More often then not, the reason they're sitting there is either because they're blown or in many cases, suffer from having dry rotted cone surrounds. These are the foam or rubber flexible rings that enable the speaker cone to flex back and forth, thus producing sound. Sub woofers tend to move quite a bit, so once the surrounds become too brittle, they can crack or disintegrate with age.If that be the case, then there's actually not much wrong with the speaker. It just needs to have these rings replaced. This Instructable will show you how you can replace these by making your own surrounds out of scrap cloth, thus enabling you to renew sometimes expensive speakers and have a fantastic stereo for next to nothing.



 
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Step 1: Preparing the speaker.

Picture of Preparing the speaker.
Before we get started, a word of warning. I've repaired quite a few set of speakers using this method, and in most cases, it works great. I once found a $1,200 pair of speakers in the trash, repaired them with this cloth method, and they were probably the best sounding set of speakers I owned. But if you didn't find yours in the trash, or they are your prized possession, then you might want to consider other options. You can in fact buy replacement speaker surround kits. They typically cost under $30 and don't take a huge amount of skill to do yourself. Additionally, since I never actually hear these speakers in their "prime" I have no idea if they sound ' as good' as they did after my repair. The repair I have here is also less cosmetically attractive as a more professional repair.

But if you're as cheap as I am or have little money to spend on speakers, this repair is for you. So lets get started. The Victim for this job is a nice JBL 10" subwoofer. First, remove the speaker from the cabinet. Secondly, gently remove the old surround from the cone. About 90% of the speakers I find use foam. This stuff usually just crumbles away. This speaker is a bit nicer and uses rubber. This speaker as many others has thicker foam pieces glued over the top of the edge of the surround.They typically come out in several pieces. Use a knife of some sort to gently pry them off. Then pull the rest of the surround off.

The next step is probably the most tricky. Making the new surround. See if you have any old scraps of cloth laying around. The best cloth to use would be a synthetic blend, tightly woven, and smooth.I've used all sorts of cloth, including canvas.But you want to use something that's flexible enough to allow the cone to move freely. Use the speaker to trace the shape of the surround to fit. Secondly, measure how far in the surround reaches towards the center of the cone. Usually the surround glues to the very edge of the cone. But since you're using cloth, you will want a tad more holding power. So measure inwards about 1/8" from the outer edge of the cone. Use a compass to mark the inner part of the cloth circle to cut out.

Once you've cut the surround out, you will want to make slight compound cuts all along with edges of the cloth, about every 1/2" or so. You do this so the cloth won't crease or wrinkle as it is being installed.
pastabiz7 months ago

This was perfect! I used a nylon 30% cotton 70% blend fabric and sealed the fabric with really watered down wood glue mixture for the last step (no spray paint laying around) and now my old speakers are working very nicely...and it didn't cost me a dime! I had been looking online for re-foaming kits and repair options when I stumbled across your post in my search. I just really wasn't interested in spending $30 for a repair kit for these particular speakers....what a lucky break for me! Thanks for sharing, you made my day :)

fast_eddie_727 months ago

I admire your creativity, but this is the long, difficult, and wrong way down a simple path. Just order foam and refoam the woofer as intended. Changing the surround material to something else will change the compliance. I order foam surrounds in bulk from MAT Electronics and they cost almost nothing. Foam surrounds are intended to be a "consumable".

Gizmocharger11 months ago
hey your idea is just pure genius! can you tell me if jeans is a good enough cloth or should I use something else?
MTJimL2 years ago
Remember that mass(weight) of the moving parts effects its acoustic properties. Too much glue will add weight to the cone and reduce the resonant frequency, possibly adversely effecting the cabinet tuning. Also, subs are long-excursion drivers and need a rolled surround, which would have to be pre-molded to the right shape, and carefully fitted so the voice coil doesn't rub. Fortunately, subs generally give more magnet gap than wide range drivers, but it's still pretty critical.
roragul2 years ago
i am repairing my jamo cd power 15's right now, but the foam is gone there is nothing left.is the foam ontop of the cloth really nessecary ? or can i be don without it aswell?

carydf3 years ago
the only thing missing is the proper alignment of the voice coils in the woofer before gluing the edges. I believe that others had mentioned this as well.
carydf3 years ago
(removed by author or community request)
mowerracer (author)  carydf3 years ago
I think you're kinda' missing the point of this instructable. Its about fixing speakers basically for free. Not to be confused with fixing speakers using the "right" materials- as in spending money for new surrounds, etc etc. In fact, I make a disclaimer at the very beginning of this post that basically says exactly what you're saying- which is that you CAN buy repair kits for these and that if you own a prized set of speakers then you might want to consider other options. But if the speakers came from the trash... well that's everyone's call. So yes- I concur with you that there is a right way and a wrong way. This is perhaps technically not the right way but it has worked fairly well for me. But again- anyone reading this should realize that yes- you can ruin a set of speakers using the cheap-o cloth method. So proceed with caution.

Anyway, the speaker I repaired in this post has been alive and kickin' ever since the repair. Over and Out.
Would you be worried about this keeping the Dry Rot in your house though? I hate to sound a little over cautious, but the spores of our dry rot was such a nightmare to get rid off that I would want to spray the speaker with some anti-fungal stuff...
i like getting speakrs of the side of the road too look at my sound system
sound system.jpg
bkay23 years ago
I've always been really interested in speakers and only recently got my first set for a pretty neat sum, as I just a student. The rubber has gone on them so they produce a raspy noise at mid levels.
This instructable has given me a summer project for after exams. I look forward to trying it. Thanks man; I'll let you know how I do!
dnorm3 years ago
you sed, 'The best cloth to use would be a synthetic blend, tightly woven, and smooth.I've used all sorts of cloth, including canvas.But you want to use something that's flexible enough to allow the cone to move freely.' ... but then you use spray paint to 'seal it', which is also gonna make it stiffer, less flexible, eh?
i just looked up 'felt' and it is 'non-woven', so it may not be appropriate, eh? but what speakers did you use canvas on, eh? tent or tarpaulin grade? def not flexible.
back in the day (dont know bout today) mfrs used rubber or foam... for a reason,eh?... trade-off between durability and expense vs. flexibility and rigidity... (i assume both rubber and foam are effectively impermeable... )

flexibility and rigidity seem to be the essential characteristics, and it is a balance point. Too rigid, the cone doesnt move, too flexible, it moves too much in unwanted ways... Trying to achieve the balance (of control of the movement of the speaker cone in the 'in and out' direction, without any side to side, with 'free movement' of the speaker cone in that direction.)

Your description (above) of the 'best cloth' says to me 'microfiber', which is 'synthetic, tightly woven, and smooth', But it is also VERY flexible... maybe too flexible, eh? The spray paint 'seals' AND stiffens it... How much in not enough, just right, and too much?... how do you judge...

What do you think of using silk?...

This is already overlong, but two more things. Back in the late 80's I had a couple of good quality JBL cabinet speakers which had the woofer surrounds deteriorated... I did not feel qualified to do the job myself, so I paid a local high end audio shop to do the repair... They never did sound right after that, sounded like they were 'stiff' or 'sticking'... I concluded, then, that the surrounds were too 'stiff'... Now, with what i have learned since, I think it is likely that they replaced the surrounds, but didnt remove the 'dome' to insure that the coil was moving freely...

I have a pair of Altec-Lansing 411-8A LF 15 Subwoofers which i bought from a friend a number of years ago, with blown ( 'gone' ) surrounds... look up the specs... recent offerings for these speakers on Ebay, with blown surrounds are at about $450 each... I only need one subwoofer for my home, i dont even want one in my car... So i fix both, keep one and sell one...

I dont wanna use a 'generic' kit for a 15 inch speaker for these babes... so I sent an email to A-L asking to get surrounds. they promise an answer in three days...

regards...

Dnorm
Mtnman0093 years ago
Thanks for posting this instructable. I am like the author and hate to see good speakers go to waste because they lack a little TLC. I have a pair of Sony speakers that have traveled with me since the beginning. I hate to admit it but I kept these over a pair of RTR's that were in need of refoaming. So as a tribute I am using this home method to repair the Sony's. Only I am doing a few things different. I went out an bought some heavy duty canvas and stretched the heck out of it then made my measurements and cuts. Then instead of using wood glue I am using a "Aleen's Flexible Stretchable Fabric Glue" I am using it as a way to hold the fabric in place but also to keep the fabric air tight for a better vacuum effect. I am going to let the glue dry for 24 hours and then test. From what I can see using the cloth as a surround is identical to how Sansui built their speakers back in the 70's. I'll keep you posted as to how they sound. Thanks again for posting this.
himno3 years ago
I am repairing my 12 inch ess speakers surrounds. My wife suggested interface as she uses it in dress making. I have found that the nature of the interface means no cuts on the outside every half inch and no need to use a slurry to paste to cones. It is flexible enough to hopefully make sure the required movement of the cone will not be hindered.They are drying at present. They look quite professional .
Thanks for posting this. I'm going to give it a shot!
master5 years ago
Ummm, there is a very easy way of doing this, and the professional way, the righter way too. Go to http://www.partsexpress.com and order a new surround kit. It is cheap, and comes with all of the things- Speaker glue, splits for when replacing, the surround and a guide. Its really simple.
when taking speakers from the trash its not likely that one would want to spend any money on them, and furthermore if you read the instructable you will see that he mentions those kits
master5 years ago
But still, I forgot to mension, nice job on using household items! This is a pretty cool idea. Also, please keep in mind, when doing this, take off the middle part, the "hump" known as the dust cap. Under there is a coil, the voice coil. Copper wires wrapped around a pole, acting as the elctromagent, which drives the speaker. When doing this, the cone could offset, offseting the voice coil off. The voice coil fits into a VERY skinny slot inside the speaker magent. If offseted, the speaker will sound bad, and damage the voice coil, dmaging the speaker. To make sure this doesnt happen, take popsicle sticks, or something even skinnier, and stick them in the skinny place I was saying, and then the voice coil will be even, in its axis.
mowerracer (author)  master5 years ago
Yup, Well aware of the kits you can buy for these. I have a pretty nice set from the 70's ( Sansui) that I rebuilt using the "correct" way. But when I was dirt-poor and 14, this is what I used to do. I figured it would be useful to others out there short on cash. Thanks for the tips!
Yeah! And like I said, this is a very neat way to use household appliences!
nanonano586 years ago
good idea thanks for sharing
You might also consider using "Shoe Goo" instead of wood glue. It's a glue made for repairing shoes that is both flexible and strong, plus it seems to stick to just about anything. You can get it at your local -blank- mart chain for about $5. I plan on using this glue when I get around to trying this myself, if I remember I'll try to post my results.
Hi. Good job on the instructable. I like that you are using home made material for the gasket. I hate to throw water on your fire. However you have a few problems that will affect the longevity and sound of the driver. The surround acts to keep the driver centered on the magnet. There is a very fine coil of wire (voice coil) that can be easily damaged by rubbing back and forth against the walls of the driver. Eventually it will start to short out, either decreasing in volume suddenly or simply dieing. Also if you make the gasket stiff with glue, you are relying on the flexability of the paper cone to allow the speaker to produce sound. Some cones have a great deal of flexibility built in so high frequencies get reproduced from the center and lower frequencies get progressively reproduced further out. You can see little rings in these 'full range" speakers that assist with this. By locking the outer area down you are decreasing the range of the driver. Now, of course, with found speakers, it probably isn't important that they have all the sound that they once did, but you are leaving some frequencies by the side of the road by not replacing the rubber surround with rubber or at least not gluing the middle area of the surround for flexibility. You can cut off the dust cover in the center, shim the voice coil up while the glue dries. This will keep it centered on the plinth. Once it's dry, remove the paper shims. You should be able to move the speaker cone in and out with your fingers and not feel any stickyness, grittyness, hanging, or grinding anywhere in the range of motion. When that' s done, you can glue the dust cover back and you are in business! You can also by kits from ebay that are specific to the type and size of driver. They come with everything you need including the rubber gasket. Once again let me say that you have done a great job with this instructable and I hope you take my comments in the positive spirit that they are ment. www.emergencydpt.com
mowerracer (author)  emergencydpt.com5 years ago
Yes, I agree that my repair is probably not the most orthodox approach. I've also repaired speakers using actual replacement foam rings. The funny thing is that I repaired a really nice set of speakers when I was in 6th grade with this method and they lasted for 10 years before I sold them. The cloth surround is actually pretty flexible. The glue isn't used to make it stiff, but just to glue it to the cone. Anyhow, thanks for the advice.
That rocks! Woah! That brings me back to my 5-6th grade times when I had so many speakers hooked up to my stereo. Thru my walkie talkie, small radios {for nighttime listening of KISS!} etc... NICE!
What kind of cloth you use?
i read Memergencydpt.com instructable, its like the pro way to do it,
but yours it the most cheapest pro way to do it, wich is great. Some speakers have a plastic cone, will it glue to it as good as the paper ones??
mowerracer (author)  hell_raiser_15 years ago
I used a cotton/polyester blend. The cloth came from a Skirt that was my Wife's before she decided to "donate" it to me. Most cloth will work. As far as plastic, I'd try maybe using contact cement. Test it out first on something else and see if it works, which it should.
Wish I had seen this a few days ago. My old Aiwa subwoofer surround foam died. It's an oddball surround size that I couldn't find a kit for on the internet. But I lucked out and found a local speaker repair shop that could do the job for $27.
mowerracer (author)  adrianwidget5 years ago
Well, $27 doesn't sound bad. It'll probably sound better than using my repair anyway. I bet I have the same speaker as you. Its also an Aiwa powered subwoofer. Its pretty heavy. That thing has an enormous amount of bass! I found mine on the street.