For about ten bucks a driver, you can replace the foam surrounds if you have some patience and determination.
There was a time when the quality of a manufacturer's equipment was what determined their success, rather than the amount of money they spend on advertising. While those days are past, much of this aging Hi fi equipment can be found on craiglist or freecycle for a song. At best, they are ready to go with a little dusting. Sometimes, however, the drivers need to be refoamed. Would you like to get started?
Step 1: Stuff to Get:
Razor blade, hobby knife, or scalpel
Stiff brush or toothbrush
Can of air
Speaker refoam kit http://stores.ebay.com/GeoAli-Vintage-Stereo-and-More
The kit I purchased included the glue, paint brushes, shims, speaker edges, and instructions.
Wood care products of choice (I'm using Howard's Restore a Finish and orange oil cleaner)
Clamps, c-clamps or the like if you have beauty rings to clamp into place.
Hair dryer or heat gun if your speakers have vanity rings around the basket ring.
Step 2: Disassembly
While the drivers are out, give the cabinets a good cleaning. Howard's Restore-a-Finish is pretty good stuff. It doesn't have much color to it but it does have some. It can really make scratches less noticeable.
I won't go into messing with the crossovers or any of that kind of stuff for this instructable. However some people would go through those systems and either upgrade the capacitors or at least test them out. I make sure they play before I take them apart and when I put them together I play them again and listen critically as possible. Make sure all the drivers work. I don't think anyone can hear the difference between one capacitator and another (of the same value.) Like $500 speaker wire, it's voodoo to sell to people: would you like me to fill your tires with scented air, sir?
Step 3: Clean the Cabinets
I clean them up nicely; maybe use a brown maker or stain marker to touch up the scratches. Use a finish restorer or just furniture polish off the shelf. You'd be surprised how nice they can look with just a good scrubbing with a rag and some off the shelf lemon or orange oil furniture spray.
I took the cloth speaker covers out to the back yard and sprayed them with 409 and the hose to get twenty years worth of nicotine out of them. The color fast synthetic material looked great when I was done. Use your head if your panels are not synthetic, woolite and a damp rag may be better. However, the synthetics were cheaper so that's mostly what I've found.
Step 4: Remove the Old Foam Surrounds
Then use your toothbrush or stiff nylon brush to remove as much of the old material as possible. Don't bother trying to remove the glue. Also if your drivers are even half way decent, they will be really tough. Don't worry about ruining them. However try not to damage the voice coil by dragging the cone up and down in the basket while you are doing all this.
In the picture below you can plainly see that there is a plastic beauty ring covering the part of the gasket or speaker edging foam where it attaches to the basket. This has to be removed. I couldn't figure it out at first but the supplier whom I purchased them from emailed me back the same day to explain the problem and give me a solution to it. I used a hair dryer to soften the glue then gently pried the rings off with screwdrivers. Worked like a charm.
Step 5: Remove Beauty Ring If You Have One
Step 6: Cut Off Dust Caps
To un-dent, use a form and a hair dryer. Soften them up with a dryer and put them over a form like a tennis ball and put them into shape. If they won't hold their shape you can use some spray starch for clothing on them.
Try not to get stuff under the dust cap. Blow them out with a can of air or compressor.
Step 7: Shim Up the Voice Coil
Keep putting the shims around and around like a the petals of a flower until you can't get any more to go in. They go in the crack between the voice coil and the magnet plinth.
Step 8: Glue the Foam Edge in Place
The kit comes with paint brushes, use them. Even though the glue dries clear, neatness counts.
Doing the inside and outside separately makes it half as likely that you will put unequal tension on the surround. This could ruin the driver. Take your time. This is really the only part of the speaker that goes bad, they will be good for another 20 years if you do them right.
Put a layer of glue on both sides of the joint. Pinch everything together with your fingers going around and around, removing excess glue with a damp rag as you go. Once you are sure you have everything touching and there is no unequal tension and no gaps, you are done.
I used the beauty rings and clamps. If you don't have the rings, then you don't need the clamps.
Step 9: Clamp on the Beauty Rings
Step 10: Allow to Dry
Step 11: Glue the Dust Caps Back On
Gaze upon the glory of your handiwork. Bask in the knowledge that you will soon have your face melted.
Remove the shims.
The speaker cones should move smoothly in and out. There should be no friction. When you push them down, they should pop back up again. When you use your fingers from behind to push the driver out to its fullest excursion, it should pop back to the center again.
Put your speakers back on the bench where they won't be disturbed. Apply glue to both the dust caps and the speaker cones where you cut them off. If you left a flap, they will just fold right over. Now is the last time to make sure there is no dust or debris under the caps.
After applying glue to both sides and flipping the caps over, put a small medicine cup upside down on each cap to hold them place. Place another cup on top of that one with some screws or whatever in it. This will hold the dust cap in place while it drys. Make sure it's lined up well. The dust cap does nothing for the sound but can be an eyesore if it's messed up.
Step 12: Reassemble Your Cabinets
Put a few drops of superglue into the screw holes where the drivers mount to the cabinets. MDF is good for one assembly (at best.) After that...meh. These Advents have Pecan hardwood faces. They wanna rock.
Make sure you put all the wires back in correct phase and on the correct drivers.
I hope you found this instructable useful. If so please rate it and comment.
No go and rock out!