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Speaker foam repair on 15" woofers

Hello all!

I have a pair of Optimus 1050 (Radio Shack) 3-way home stereo speakers that are about 20 years old. The foam ring that goes between the outer edge of the cone and the steel frame of each 15" woofer is starting to split/tear. The speakers still work, but I know it's not a good idea to run them once the split goes all the way around. Looking around the net, several places sell repair kits for this.

I have never done it before, but it seems fairly straightforward, except for one thing: there appears to be a difference of opinion on whether you need to remove the dust cap and stick shims in between the voice coil former and the pole piece to center the cone or not. Some places say you do, while others seem to prefer moving the cone by hand and centering it before the glue on the new foam dries completely. Which way does the group prefer?

These are not audio pile speakers. I think I paid $100-$120 each (on sale) new, and I think I can get complete replacement woofers for $40 or $50. The main idea here is to get working speakers for less money than replacing the woofer or the whole speaker. The kits vary in cost and also in what they include. Is there any US supplier that stands out?

Thanks!

Matt Roberds

Reply to
mroberds
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I vote for shimming, it really can't hurt, and as long as you don't get dirt into the open gap, yhou should be fine.

Reply to
hrhofmann

I did 6 Advent woofers. The first kit included shims to keep the voice coil centered and had new dustcaps. I did what they said and it works fine. The later kits did not include shims and even though I had them, I did not use shims or replace the dustcaps. Those drivers also work fine.

It isn't difficult or even tedious but you do have to wait for the glues to cure.

I don't vote for shims as it requires careful removal of the dustcap to NOT damage the voice coil leads. Never disassemble more than necessary.

G²

Reply to
stratus46

If you go the shimming route. I mark across the dome to cone join as a reference , then cut a neat ring with a narrow tip scalpel. Shims 3x 2mm wide strips of credit card. Reglue the cone with thin hotmelt string and felt-tip/painted black glue line, easier if you ever have to remove again. Unless the cones are on view, no cloth cover, then a more cosmetic glue line required

Reply to
N_Cook

Use the shims. Leave them in until the glue dries. If you are patient and steady you will do fine. Check YouTube for vids.

Reply to
dave

As a curiosity, would applying a small voltage across the voice coil keep the cone centered without causing other problems? (small--1, 2, maybe 3 volts)

Mikek

Reply to
amdx

The dust cap is usually ready to fall off by the time the foam dissolves. Otherwise dampen the joint slightly with plain water, wait a few, and lift it off with a hobby knife. If you are worried about debris, use gravity and/or a well placed rag to protect the gap.

Reply to
dave

I have made shims from plastic water bottles, theatrical gels and the old stand-by "collar stiffeners" for dress shirts. Use at lest 3 and split the gap distance all the way around. Symmetry and full range of unimpeded motion are the goals. Patience is THE virtue.

Reply to
dave

I was originally thinking a DC voltage, and then had a second thought, How about a 20khz low voltage signal, wouldn't hear it, but it may keep things centered, or even force the fresh glue joint to move and release any tension you/it may have caused installing the foam ring.

Mikek

Reply to
amdx

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Just like it's not a good idea to use your car when the tire pops off the rim.

Reply to
William Sommerwerck

Thanks for the responses! It will be a week or two before I get to fixing these speakers; I'll post back with results.

Matt Roberds

Reply to
mroberds

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