when re-foaming a surround on a speaker use shims

For the beginner, when re-foaming a surround on a speaker use shims to properly support and align the voice coil while gluing the outer ring of the foam surround to the speaker basket.

There are dozens of DIY How-To Videos showing that the dust cap does not need to be removed by using a 9 volt battery, the by hand method, using clothes pins and even downloading a signal generator app on a mobile phone and inputting the 50hz signal to the speaker. I know first-hand for the beginner; someone like me who wants to repair only one set of speakers and has no experience, the shim method is the correct method and will not fail when used. The other methods may cause undue stress, torn new expensive foam surrounds and the need to purchase more. My grandfather always said, " A job worth doing, is a job worth doing right, the first time." I destroyed an expensive Infinity 10" foam surround thinking it was as easy as so many had stated. I am witness that this is not so.

As far as where to purchase foam surrounds? I purchased from two different sources.

The first vendor was slow to respond, it took a few days, but they did respond. I am not faulting the vendor for my failure as this is completely my fault. I'm sure experienced speaker repairers can replace foam surround by hand "feel" and folks out there who've never done this before will have no trouble using one of the methods stated above. In my case I replaced two 10" foam surrounds, was successful with one but, failed with the other.

The second vendor I contacted immediately answered the phone when I called, added shims to the order, was very understanding and extremely helpful! I am not sure if I am permitted to mention company names on the forum. The company that was really truly helpful is located in the upper Midwest U.S. in the land of 10,000 Lakes. I took my time and removed and re-used the dust caps. I caused no damage to the cone or the cap. It took a little longer to "do it right" but, was well worth it. I did 5 speakers in this manner; two 5" mid-ranges, two 6.5" mid-woofers and one 10" woofer.

I've completely refurbished my speakers today by replacing all of the foam surrounds by using shims and will finish the job tomorrow. After a few hours of allowing the glue to set, I removed the shims and re-installed the dust caps. There is no rubbing of the voice coils. The speakers look brand new. I am excited and can't wait to hear them restored! They are Infinity Reference Six's.

This "write up" is for the fellow "new-bee"; I hope this has been helpful. While I realize this is common sense to some, it isn't intuitive to those that have never "done the job of re-foaming" a speaker before. While How-To videos are very helpful, they might lead someone astray, It was embarrassing, costly and then enlightening. My suggestion, use shims, take your time and you will achieve great success.

 

I re-foamed my old Sony speakers without shims and it worked out fine. YMMV.

 

I’ve done it both ways and had success. Really though, the shim method is no more difficult or time consuming than the other. You don’t even need to totally remove the dust cap either. With an exacto knife, carefully cut around the base of the cap unto you have about 90% of the circumference cut. Gently pry back the cap, shim, and replace your surround. When everything is finished you can then reglue the cap. If you operate with a careful and delicate touch you’ll never see the cut.