Itching fingers......

We do not question the statement that many 'badly refoamed woofers' are offered at professional repair places at a regular base, but from our experience (having over 20.000 satisfied customers worldwide we consider DIY....) many, many, many times people can do it using the çloth peg method'.

About the 'original' replacement woofers, we just want to tell you this might seem a nice solution, but please ask the date of production before buying! If the units are old (> 10 years) but have been shelved the foam ring will still be effected, although less than in a living room environment, but you have to refoam soon, guaranteed!!! Another issue with these replacement woofer is that the design flaws (like the dried out 'cracking' rubber rings in the Beolab series are not resolved - you will suffer from the same problem soon! Sometimes replacing the ring is the only option.

Then the bad-sized rings - true. Be careful what you buy. Look on the internet and find a trusfull seller, or a seller you trust. One thing to check might be how often the seller sells. If the seller had his foam rings produced in 2003 and is selling those now...... If you get what I mean. Fresly pressed foam ring have a longer lifespan than rings that have been shelved for years....

The discussion also seems to turn into an A versus B discussion. If you have the confidence to shim, you have the tools to shim, you can do so. But if you don't, you will still be able to refoam a speaker. It's no rocket science!

Fianlly, for those who have no experience, before you refoam that precious woofer, maybe practice on a cheap woofer you can get from a second hand shop for a scatch. But be careful, after having a succes you want to do it again!!!!

Kind regards,

Good Hifi

Great job Leslie! Your S80 look very nice.

For my MC-120.2s I chose the Martin option. Of course he did a great job for not that much outlay.

He uses shims.

I have repaired many woofers in the past but for those I wanted a professional touch to the job because these speakers would be my main ones, and I wanted to keep them mint.

Yes, it is quite possible a job to do, but then there is always the glue problem. Martin has special tools I believe to get the foams perfectly round and centered, and commercially available glue is not ideal from my experience.

Good Hifi have indeed a good feedback, but I think their—your!—video tutorial should be of better quality!

Good Hifi:

The discussion also seems to turn into an A versus B discussion. If you have the confidence to shim, you have the tools to shim, you can do so. But if you don't, you will still be able to refoam a speaker. It's no rocket science!

My two cents, as we say in the States.

First, a summary of my limited experience.

For the six eight inch woofers I have refoamed, I cut off the dust cap, used shims, used a new (slightly larger) dust cap.  100% success rate so far.

For the two CX50s I refoamed, I did not shim, did not use a battery, did essentially nothing to center the foam to the basket except "use feel."  This method worked fine, but I wouldn't recommend it, nor would I even try to describe it to someone who wanted to use the method.

Conclusion:  my limited experience puts me square in the shimming camp, but I do know other methods can and do work.

And for the record, I have used Woofer Repair each time and recommend them based on their products and service.

PS  I believe Martin is now in the "don't try this at home" camp, and recommends seeking out a professional.

PPS  As always, good work Leslie.  That is a beautiful loudspeaker.

Thanks Rich! Certainly is a beauty like your Avatar

I feel the need to add my own comments here. Experience has taught me that whenever possible you should ALWAYS shim when refoaming drivers. It is the ONLY way to guarantee correct coil centering & height of the cone when attaching the surround. I use strips of acetate sheet.

OK - there may be certain drivers where this isn't possible but this should be the exception & not the rule.

As for the type of adhesive - I used some so called "special glue" from a supplier of foam surrounds. The foam surrounds started peeling away after a couple of weeks. I should have known better when I was applying it as it was very simlilar to PVA (it probably WAS PVA) but decided to give it a try. I now use only correct speaker cement.

Martin isn't in the "don't try this at home camp" at all, he simply thinks the same as myself. If you aren't 100% confident in what you are doing & choose to ignore well established & proven methods then you shouldn't be doing it! I too have had many botched attempts at refoaming land on my doormat from people who thought they knew best (incorrectly centered coils being the most common problem). Many of these botched attempts are so poorly executed it means the end of the drivers.

Chris.

All drivers I have refoamed mostly CX50/100 are done  with the shimless method and never had any complaints what so ever!

Congratualtions Leslie I'm sure you are happy with your method of refoaming - but you should see the state of some CX50/100 drivers I have received which were refoamed using the "shimless" method. Just because you claim it as being successful for you doesn't make it the correct way of doing things.

The bottom line is that shims should be used whenever possible - it is the correct way of refoaming & nothing anyone says will change that. I would certainly never encourage any other method if you want guaranteed results.

Chris.

Leslie is very skilled in many ways and I admire most of his work.
I do agree with Chris, though, in that shim'ing is an absolute must when refoam'ing woofers.
Just as important as using the right glue and keeping the workspace clean.
Leslie is either very skilled or just plain lucky - or both.

It's a fact that some people are better cut out for DIY than others.
Leslie may have a good feeling about things, refoaming a.o. From seeing what he has accomplished,
I feel it safe to say, he has and therefore he has a high succes rate but, as Chris have also found out, not
all people have this feeling.
By far.
Some people decide to stop when they find out that their skills aren't adequate and while there is still
a chance of rescuing the driver, others just speed ahead.

The owner of these CX50 never got around to glueing anything.
He removed the old surrounds and it didn't quite work out as in the Youtube video...

I've seen glue "strings" across the cone and down the center.
I've seen cones that had the outer edge where the old foam sat cut off with scissors, leaving nothing for the new surround to sit on. A full MS150 set...
I've seen drivers with torn cones and the likes.
I've seen spiders pulled and stressed completely out of shape.
I've seen surrounds mounted using building silicone - lots of it.
I've seen deformed coil formers from owners forcing the included cardboard shims down a gap that was only about half the width.
I've seen cones with strange wrinkles and cones that were "extended" using paper to reach out and fit a new non-correct diameter surround.
Hot glue melts some types of foam, don't ask how I know.
Everytime a battle to save an extinct B&O driver and everytime I'd wish they'd asked a pro.
It's not expensive to have it done by a pro. About the same price as one of the cheapest and lousiest replacement
drivers that won't have nowhere near suitable T/S parameters anyways.

Even owners who actually tried to shim everything up correctly can face tough luck.

This woofer came from a fellow Beoworlder on the other side of the globe. He had it refoam'ed by a pro but
it "didn't sound quite right".
I took this photo when I found foam remains caught and mashed out between the coil former and
magnet center piece. That sticky stuff is very difficult to remove.
The refoam job itself was perfect, the guy who did it just wasn't aware of a tiny piece of old foam debris.
There are many ways for things to go wrong, even if you try to do it right.
Shim'ing and making sure everything sits correctly, is the least thing you can do.

Martin

Dillen:

The owner of these CX50 never got around to glueing anything.
He removed the old surrounds and it didn't quite work out as in the Youtube video...

The kids these days have a phrase that seems to fit this situation.

"Wow.  Just wow."

Finally Martin, you're back!

I'm convinced, because of all these good advises that shimming is a need to do refoaming the right and precise way. However, and I have not done this shimming method before, I wonder if this is really necessary for small diameters like CX50/100 drivers? Other thing is, would people with no experience at all take risks by damaging the cones/spider. I mean, you have to cut out the dust cap (if I have understand this correctly, you have to make sure no dust will come inside the center cone etc. Would be great if someone could make a sort of photo session while doing this refomanig/shimming process!

Leslie:

Would be great if someone could make a sort of photo session while doing this refomanig/shimming process!

Yes it would.  Then turn it into a wiki on the new forum.

Leslie, if you want a DVD of the whole process, PM me your mailing address and I'll send you one.

Martin, I've seen your pictures an they look worse! What do you think these kind of people would handle when using the shimming method. They should keep their hands off refoaming at all!

Rich:

Leslie, if you want a DVD of the whole process, PM me your mailing address and I'll send you one.

That's a nice offer Rich, would you do that for me?

Leslie:

Rich:

Leslie, if you want a DVD of the whole process, PM me your mailing address and I'll send you one.

 

That's a nice offer Rich, would you do that for me?

Of course.

Leslie:

Finally Martin, you're back!

I'm convinced, because of all these good advises that shimming is a need to do refoaming the right and precise way. However, and I have not done this shimming method before, I wonder if this is really necessary for small diameters like CX50/100 drivers? Other thing is, would people with no experience at all take risks by damaging the cones/spider. I mean, you have to cut out the dust cap (if I have understand this correctly, you have to make sure no dust will come inside the center cone etc. Would be great if someone could make a sort of photo session while doing this refomanig/shimming process!

I'm onto it in the new forum, there will be a full wiki, will finish this weekend,

Leslie:

Rich:

Leslie, if you want a DVD of the whole process, PM me your mailing address and I'll send you one.

 

That's a nice offer Rich, would you do that for me?

Leslie,

There a some photos of the small drivers being shimmed on this thread after the battery method is illustrated:  http://forum.beoworld.org/forums/t/36917.aspx

My first re-foam was a set of C75's and I discovered a slight rubbing sound on one driver a few weeks later.  I re-did it with shims, and wished I would have done them all that way to begin with.  The stiff little dust caps are pretty easy to cut and fold back and re-glue in the same place.  I use the stuff called  tacky glue.  

Steve

Just had a quick view Steve and I already saw this thread but I can't see any shimming. Just the battery method, or is that shimming? Now I'm really confused

It's after the battery method at the bottom of the first page.  It's my entry.

Leslie:

Martin, I've seen your pictures an they look worse! What do you think these kind of people would handle when using the shimming method. They should keep their hands off refoaming at all!

Yes.
As said, not all people are cut out for DIY. Some are definitely NOT.
Only last week, an owner told me "The screwdriver slipped when I took the woofer out...".
*sigh*.
What may seem a piece of cake to you may be quite a task for someone else, maybe downright impossible.
CX50/100 are not too tight but I can assure you, it CAN go wrong if you don't shim them.
If the drivers played (or just stood) for a long time with bad surrounds, the weight of
the cone etc. will deform the spider (and sometimes even the cone itself). Not a lot, not even visible
but enough to cause the coil former to start rubbing a couple of weeks after being refoam'ed when things
are slowly settling again.
In severe cases, that can happen even if you shim'ed it. Therefore I often mark the drivers
with up and down and often ask the owners to do so too before sending drivers to me.

And why not shim ?
It's not particularly time consuming (this is hobby for us, right ?), it's not particularly difficult and
it's not even expensive and it does give you a better chance of success.

The general advice, I think, should be:

- If you feel, you are very good with DIY jobs and have a good "mechanical feeling and touch", you
may be able to refoam speaker drivers yourself. Aligning the coil is what the factory did and it's
highly adviceable to do the same.
However, if you, while you work, suddenly feel that you are in too deep or face an unexpected issue - STOP!

- If you don't feel 100% up to the task, leave it someone who is, right from the beginning.
Prof refoam'ers are worth their cost and those unique B&O woofers are not too plentyful.
If you have to redo a refoam job for some reason, you will already have lost the amount of money a pro refoam costs.

Personally, and as a Beoworld Technical Advisor, my advice is to let someone do it for you.
Someone who has done hundreds before. Someone who don't need your woofers to be the
first ones to practice on.

Martin

Rich:

Leslie:

Rich:

Leslie, if you want a DVD of the whole process, PM me your mailing address and I'll send you one.

 

That's a nice offer Rich, would you do that for me?

Of course.

Thanks Rich, much appreciated! What a great and helpfull place this is!

Dillen:

Someone who has done hundreds before. Someone who don't need your woofers to be the
first ones to practice on.

Next time when I have to visit Denmark I will drop by, thanks Martin

Here is my contribution regarding faulty repairs - an S80.2 driver professionally refoamed incorrectly. I wrote up a thread on this about a year ago.

Completely out of center? Is that what I see Eugene?

Leslie:

Completely out of center? Is that what I see Eugene?

You are about half right Leslie

Take a look at your surround installation then a closer look at mine. You will eventually spot the difference.