Large Advent LoudSpeaker Refoam Advice

Im looking for advice. I have a set of steel cage Advent Loudspeakers (i believe they are the A3).

i PM'ed KingBubba because i did a set of these not to long ago.

I thought his advice was pretty darn good so i thought i would post it publicly (hopefully he is ok with that).

"Refoaming is a great skill to learn and apparently Advents are a good woofer to start on. I did my first refoam by using shims because the seller had started a refoam and failed it and the dust caps were already off. It went well and the tension of the shims in the former allowed me to lift the cone high up in the frame to glue the underside of the cone for the foam.

First, download a free program called TrueRTA. It is a spectrum analyzer program that also has the advantage of having a tone generator. You want this because the easy way to refoam these woofers is not using a shim but instead feeding a tone into the speaker as the glue is drying. Use your computer to send the tone to an amp that will be used for your refoaming.

First step is to clean the cone and frame to the best of your ability. I used lacquer thinner or acetone to assist in this process. A Dremel tool is also a help for the frame.

Second step is to use a medium grit sandpaper to smooth out the surface of the frame and the cone. I use Aleenes Tacky Glue. I picked up a stiff bristle artists brush about 1/3" wide and cut the long handle down to make it easier to use. I rounded the handle with a file and sanded it down.

The third step is to attach a AA battery to the speaker with the positive to the negative. This will suck the cone into the frame, keeping it out of the way. Next apply the glue to the frame and then the backside of the foam. Let the glue dry for about two minutes. Don't use gobs of glue, just enough to cover well. After about two minutes apply the foam. I personally stay with the glue until it dries and use the back of the brush handle to press down the foam onto the frame as it dries. I like to use Aleene's because it dries slow and is forgiving to repairing errors. This makes refoaming slower. You will have to make your own choice about what glue to use. Reedger's glue is probably similar to Aleene's. When the glue is dry you can remove the battery.

Before you start step four, let the glue dry fully, at least an hour if not more. Next switch the battery so that positive is to positive and this will push the cone out which exposes the underside of the cone easier. Work the foam around the cone to get it under the cone. I then use the brush and carefully apply the glue to the foam and the cone at the same time. Once the glue is on all surfaces, I disconnect the battery and let the cone just fall onto the foam. In theory it should be centered when it does that. This is the time when I hook up the amp to the driver and apply a 30 - 40 hz tone at a very moderate level, audible but not loud. This tone will let you know if your cone is centered. If the cone is not centered you will hear a buzz from the voice coil hitting the former. This is when I appreciate the slowness of Aleene's glue. If you hear a buzz you will be able to adjust the cone one direction or another to get it centered. Once again I use the butt end of the brush and constantly keep up the pressure on the foam and cone to make sure the foam stays glued to the cone and doesn't slip off center.

Once the glue is set I will discontinue the tone and apply some regular music at a modest level and let it play for 15 minutes or so but never loud.

That is my routine. It is not the same as others but it works for me. Some people like a fast drying glue and I imagine the better you get at refoaming, the more reasonable that would be. Also if you were in the business of refoaming, you would not want to spend ten minutes on each drying cycle to fuss with the glue.

Good luck with your project."

Any other advice before i start the project?
Thoughts, Suggestions etc??

Thanks!

The only thing I would strongly disagree with is gluing the foam to the basket first, then the cone. That's a real good way to get something off-center, I'd think.

that is what i was thinking as well but how do you get the foam to stay straight while under the cone? THe glue must have to be fairly tacky

I must apologize to everyone about this because I did have the steps backwards, Absolutely! I'm not sure what I was thinking when I wrote my PM. :scratch2: Always do the cone first. Scale21 I'm sorry about my error. And I do hope you have not started. My apologies to you and all.

Here is how my PM should have been written:

"Refoaming is a great skill to learn and apparently Advents are a good woofer to start on. I did my first refoam by using shims because the seller had started a refoam and failed it and the dust caps were already off. It went well and the tension of the shims in the former allowed me to lift the cone high up in the frame to glue the underside of the cone for the foam.

First, download a free program called TrueRTA. It is a spectrum analyzer program that also has the advantage of having a tone generator. You want this because the easy way to refoam these woofers is not using a shim but instead feeding a tone into the speaker as the glue is drying. Use your computer to send the tone to an amp that will be used for your refoaming.

First step is to clean the cone and frame to the best of your ability. I used lacquer thinner or acetone to assist in this process. A Dremel tool is also a help for the frame.

Second step is to use a medium grit sandpaper to smooth out the surface of the frame and the cone. I use Aleenes Tacky Glue. I picked up a stiff bristle artists brush about 1/3" wide and cut the long handle down to make it easier to use. I rounded the handle with a file and sanded it down.

For the third step, start by attaching the battery so that positive is to positive of the driver; this will push the cone out which exposes the underside of the cone to make it easier t access. Work the foam around the cone to get it under the cone. I then use the brush and carefully apply the glue to the foam and the cone at the same time. Don't glue the roll in the foam. Once the glue is on all surfaces, wait two minute for the glue to dry a little and then disconnect the battery and let the cone just fall onto the foam.. I personally stay with the glue until it dries and use the back of the brush handle to press down the foam onto the cone as it dries. I like to use Aleene's because it dries slow and is forgiving to repairing errors. This makes refoaming slower. You will have to make your own choice about what glue to use. Reedger's glue is probably similar to Aleene's. When the glue is dry you can remove the battery.


Before you start step four, let the glue dry fully, at least an hour if not more. The fourth step is to attach the AA battery to the speaker with the positive to the positive. This will push the cone and foam away from the frame, keeping it out of the way. Next apply the glue to the frame and then the backside of the foam. Let the glue dry for about two minutes. Don't use gobs of glue, just enough to cover well. After about two minutes disconnect the battery and the cone and foam will drop into place. In theory it should be centered when it does that. This is the time when I hook up the amp to the driver and apply a 30 - 40 hz tone at a very moderate level, audible but not loud. This tone will let you know if your cone is centered. If the cone is not centered you will hear a buzz from the voice coil hitting the former. This is when I appreciate the slowness of Aleene's glue. If you hear a buzz you will be able to adjust the cone one direction or another to get it centered. Once again I use the butt end of the brush and constantly keep up the pressure on the foam and frame to make sure the foam stays glued to the cone and doesn't slip off center.


Once the glue is set I will discontinue the tone and apply some regular music at a modest level and let it play for 15 minutes or so but never loud.

That is my routine. It is not the same as others but it works for me. Some people like a fast drying glue and I imagine the better you get at refoaming, the more reasonable that would be. Also if you were in the business of refoaming, you would not want to spend ten minutes on each drying cycle to fuss with the glue.

Good luck with your project.

Gary "

ah perfect!!

That is the exact reason i posted your PM response. It sounded a bit strange to do the cage before the cone and thought i would pipe up to see if anyone had heard of this advice.

Very very good write up by the way.

No...i havent started yet. Ill be doing that shortly.

Heck......i need to find me a AA battery around here somewhere

I don't drink any more so it couldn't be that. I'll try to pay better attention in the future. :yes:

KingBubba said:

I don't drink any more so it couldn't be that. I'll try to pay better attention in the future. :yes:

Click to expand...

Thanks again for the great write up. I think ill do the inside (cones to foam) tonight and maybe the outside (foam to frames) tomorrow after work. That should allow ample dry time

SO do you run a small bead around the seam on the top side once the glue sets up to provide for a perfect seal from the top like is shown on many refoaming sites? Or ...is this only done on foam that would typically sit on top of the cone?

I did on my first pair but since I keep after the glue as it is setting up I don't any more.

I think the main reason for the extra bead of glue around the seams is to seal any loose edge flaps that may buzz during speaker operation.

If you use enough during the initial gluing, however, it isn't really necessary.

Doug

I have foamed SEVERAL woofers and Im giving you fair warning, the battery trick does not always work! The only way to guarantee the voice coil is perfectly aligned is by cutting the dust cap and shimming the coil. This also lets you properly align the spider. The way you describe sounds like you are just letting it fall in place where ever it may fall when you unhook the battery? I have only had the voice coil rub after re-foaming on two woofers, both of which were done without shimming!

Just wanted to share my thoughts!

Happy re-foaming!!

The true purpose of shimming is NOT to center the former/ voice coil but to properly align the voice coil vertically in the gap! The spider should actually center the voice coil horizontally.
DC

GENXVINTAGE said:

I have foamed SEVERAL woofers and Im giving you fair warning, the battery trick does not always work! The only way to guarantee the voice coil is perfectly aligned is by cutting the dust cap and shimming the coil. This also lets you properly align the spider. The way you describe sounds like you are just letting it fall in place where ever it may fall when you unhook the battery? I have only had the voice coil rub after re-foaming on two woofers, both of which were done without shimming!

Just wanted to share my thoughts!

Happy re-foaming!!

Click to expand...

He actually acknowledges that concern in this portion of the instruction:

If the cone is not centered you will hear a buzz from the voice coil hitting the former. This is when I appreciate the slowness of Aleene's glue. If you hear a buzz you will be able to adjust the cone one direction or another to get it centered. Once again I use the butt end of the brush and constantly keep up the pressure on the foam and frame to make sure the foam stays glued to the cone and doesn't slip off center.

Click to expand...

Otherwise just using the battery method or any method only assuming it's centered without at least checking for voice coil rub is risky. Many instructions recommend at least manually pushing the cone in and out. The sound of voice coil rub is unmistakable.

well i did use the battery trick along with TrueRTA. They are drying now. I think they turned out pretty good although just a tad sloppy with the glue It is my first pair so ill cut myself some slack. All that matters is how good they sound after im done.

I'll be doing my second pair of JBLs soon. I did my first pair with the same method and had no trouble regardless of the fact that JBLs have a reputation of a very narrow magnet gap which makes it tricky. I'm hopeful that your experience has been a good one and will be the start of more successes in your future. The more idiots like us that can fix these thing, the fewer great old speakers will be off to the landfill. To me that is a good thing.

JBL resurround with pics, using test tone: http://www.audioheritage.org/vbulletin/showthread.php?t=469

I re-foamed my volkswoofer recently and it was a pain in the ass. two things required to get the job done, patience and more patience. good luck to all refoamers. (just invented a word, nice)

terra1 said:

He actually acknowledges that concern in this portion of the instruction:



Otherwise just using the battery method or any method only assuming it's centered without at least checking for voice coil rub is risky. Many instructions recommend at least manually pushing the cone in and out. The sound of voice coil rub is unmistakable.

Click to expand...

If they are even a slight bit off center you wont hear the rub untill you crank that volume up!!

Here is a few I have recently refoamed by shimming. Also reused the original dust cap on all these!

is that your shop by any chance. That is a cool bench! I wonder what that thing is? An old desk? A custom bench? Neat anyway....

the refoam is complete.

I have them back in the cabs now and the cabs didnt turn out too bad. I used these as a test bed for future projects and i must say it is pretty impressive what can be done with speakers that were pretty dang rough!

They will be going into a stacked setup with another set i have. Im working on trying to build stands that will raise them up. ANyone have any advice on how high to have your stands for a stacked system?

Thanks for all the help guys. I think they turned out pretty good! Ill post pics once i get them setup proper.

i have one DONKEY sized question.
With the large advents......and the speaker cable. How do you attach the speaker wire to the binding posts? Do you just strip the bare wire and screw it down behind the post or do you crimp and solder on somthing more elegant

Big thanks to the foam guy Reedger! Things worked out great with his outfit.

I use bare wire because I like to rotate my speakers. Some have those plastic push in terminals.

I have thought about applying some solder to keep the strands from fraying just never got around to it.