Refoaming woofers
- Thread starter DSChamber
- Start date
terra1
Addicted Member
It depends on how comfortable you feel either way.
Take a look at post #4 with revised instructions on the battery method:
http://www.audiokarma.org/forums/showthread.php?t=154942
I used the battery method outlined, but did not play a tone or music through the speakers. I just disliked the thought of cutting and thought I would try it without shimming. There are those who believe shimming is the best way.
You can test how comfortable you may feel about not shimming by testing the driver. Push the cone of your driver in and out. Do you hear the voice coil scratching? If you do, can you move it a little in one direction like 1 o'clock 4 o'clock, 8 or 10 o'clock without hearing any rub?
When you hear it not rub and quietly move up and down, that is what you want.
If you can't get a consistent feel for eliminating the rub, then you may want to cut and shim.
I only followed seller instructions pushing the cone in and out to check for voice coil rub. It's important to adjust the surround as needed. That's why the slow white glue may be best for beginners.
I did my Advent 5002, Boston Acoustics A100, Cannon TLS 1232 successfully without cutting the dust cap and shimming.
I goofed on one of my Kenwoods. I didn't find the sweet spot and I knew I had some rub, but I glued it anyway. Lessons of a newbie. Now I have to redo it because I know I can shift it a little to eliminate the rub. I have been pressing the cone in different directions while playing music and find if I move it towards 2 o'clock rub is eliminated. Patience, patience, patience. It wasn't because of the method, it was because of my impatience. I should have followed KingBubbas advice and adjusted by pushing the cone with the butt of the brush as needed and test alignment and voice coil rub while drying.
As Shakespeare would say, To shim or not to shim, ... Ay, there's the rub ...
UPDATE 11/08: I redid the surround that rubbed and and removed the dustcap. There is no consistent clearance. The problem is with the driver itself and I will be looking for replacement. No amount of adjusting helped.
***********
Pictures attached below from simplyspeakers tutorial show how to test for voice coil rub. I would actually do this as it is drying to see if adjustments need to be made. Only a light touch is needed to flex the roll only. You don't need to push it so far that you shift the glued flap on the frame. You only want to reposition the flap if you need to move the cone in a direction to correct any voice rub.
Picture tutorial from simplyspeakers
http://www.simplyspeakers.com/speakerrepairinstructions.htm
Here's a nice video from Speaker Works Northwest that gave me the courage to try refoaming on my own:
http://www.speakerworks.com/speaker_repair_video_s/62.htm
Click on the 56k or Cable/DSL depending on your connection
Take a look at post #4 with revised instructions on the battery method:
http://www.audiokarma.org/forums/showthread.php?t=154942
I used the battery method outlined, but did not play a tone or music through the speakers. I just disliked the thought of cutting and thought I would try it without shimming. There are those who believe shimming is the best way.
You can test how comfortable you may feel about not shimming by testing the driver. Push the cone of your driver in and out. Do you hear the voice coil scratching? If you do, can you move it a little in one direction like 1 o'clock 4 o'clock, 8 or 10 o'clock without hearing any rub?
When you hear it not rub and quietly move up and down, that is what you want.
If you can't get a consistent feel for eliminating the rub, then you may want to cut and shim.
I only followed seller instructions pushing the cone in and out to check for voice coil rub. It's important to adjust the surround as needed. That's why the slow white glue may be best for beginners.
I did my Advent 5002, Boston Acoustics A100, Cannon TLS 1232 successfully without cutting the dust cap and shimming.
I goofed on one of my Kenwoods. I didn't find the sweet spot and I knew I had some rub, but I glued it anyway. Lessons of a newbie. Now I have to redo it because I know I can shift it a little to eliminate the rub. I have been pressing the cone in different directions while playing music and find if I move it towards 2 o'clock rub is eliminated. Patience, patience, patience. It wasn't because of the method, it was because of my impatience. I should have followed KingBubbas advice and adjusted by pushing the cone with the butt of the brush as needed and test alignment and voice coil rub while drying.
As Shakespeare would say, To shim or not to shim, ... Ay, there's the rub ...
UPDATE 11/08: I redid the surround that rubbed and and removed the dustcap. There is no consistent clearance. The problem is with the driver itself and I will be looking for replacement. No amount of adjusting helped.
***********
Pictures attached below from simplyspeakers tutorial show how to test for voice coil rub. I would actually do this as it is drying to see if adjustments need to be made. Only a light touch is needed to flex the roll only. You don't need to push it so far that you shift the glued flap on the frame. You only want to reposition the flap if you need to move the cone in a direction to correct any voice rub.
Picture tutorial from simplyspeakers
http://www.simplyspeakers.com/speakerrepairinstructions.htm
Here's a nice video from Speaker Works Northwest that gave me the courage to try refoaming on my own:
http://www.speakerworks.com/speaker_repair_video_s/62.htm
Click on the 56k or Cable/DSL depending on your connection
Attachments
DSChamber
Well-Known Member
Well I emailed ML Sound (John) and I have to say that he is very very helpful. Unfortunately according to him I won't find a replacement surround anywhere.... seems that a 8" cone isn't an industry standard and I will not be able to find a replacement.
From what I can tell I would need a replacement surround that has an outside diameter (the edge which glues to the basket edge) of either 9 5/8" or 9 1/2"s... 9 5/8"s would be a perfect fit as this is the exact diameter of my baskets and old surrounds.
The inside diameter is what is causing me major concerns... my original surrounds glue to the back of the cones and are angled... so the diameter of the inside roll edge would be 8".... seems this surround doesn't exist
What John is suggesting is for me to go with a 7" inside diameter surround (one for a JBL125 10" woofer) and basically trim off approximately 1/2" of my cone and then put the surround on the top of the cone rather on the rear... the JBL woofer surround seems to have a wider roll which would make up the difference
I dunno... I am very disappointed that there isn't a replacement surround, and even more disappointed that I will have to cut off 1/2" of cone in order to get my woofer back working :tears::sigh:
Anybody have anything to suggest before I put the sharp knife to my cones? :tears::sigh:
From what I can tell I would need a replacement surround that has an outside diameter (the edge which glues to the basket edge) of either 9 5/8" or 9 1/2"s... 9 5/8"s would be a perfect fit as this is the exact diameter of my baskets and old surrounds.
The inside diameter is what is causing me major concerns... my original surrounds glue to the back of the cones and are angled... so the diameter of the inside roll edge would be 8".... seems this surround doesn't exist
What John is suggesting is for me to go with a 7" inside diameter surround (one for a JBL125 10" woofer) and basically trim off approximately 1/2" of my cone and then put the surround on the top of the cone rather on the rear... the JBL woofer surround seems to have a wider roll which would make up the difference
I dunno... I am very disappointed that there isn't a replacement surround, and even more disappointed that I will have to cut off 1/2" of cone in order to get my woofer back working :tears::sigh:
Anybody have anything to suggest before I put the sharp knife to my cones? :tears::sigh:
DSChamber
Well-Known Member
The JBL surrounds have a bigger roll, apparrently the roll is almost 3/4" wide... this would probably more than make up for what I will lose on the cones.... I think by going with a 7" inside diameter surround the following is true...
Current cone diameter is 8" with a roll width of 1/2"... effective diameter of my current woofer would be 8 1/2" (cone diameter plus 1/4" of roll on either side)..I think the woofer is measured from the center of the cone to the tip of the roll.
New diameter would be (considering I will have to cut off 1/4" all the way round and new surrounds would be top glued instead of back glued)
8" - 1/2" = 7 1/2" new cone diameter
7 1/2" + 3/4" (JBL surrounds have a 3/4" roll width) = 8 1/4"
So will be loosing 1/4" of effective cone diameter.
Is this correct?
Current cone diameter is 8" with a roll width of 1/2"... effective diameter of my current woofer would be 8 1/2" (cone diameter plus 1/4" of roll on either side)..I think the woofer is measured from the center of the cone to the tip of the roll.
New diameter would be (considering I will have to cut off 1/4" all the way round and new surrounds would be top glued instead of back glued)
8" - 1/2" = 7 1/2" new cone diameter
7 1/2" + 3/4" (JBL surrounds have a 3/4" roll width) = 8 1/4"
So will be loosing 1/4" of effective cone diameter.
Is this correct?
terra1
Addicted Member
The absolutely last thing I would do is cut the cone. I would rather glue the surround on top only rather than cut.
Even my Advent has a 7 1/2" cone and I was able to find surrounds for that.
With a 7 1/8" inner dimension of the surround and an 8" cone, that would mean you have 7/8" difference. Remember you have a circle. So half of 7/8" would still give you more than 1/4" overlap by the surround around the whole cone.
I would keep looking and asking.
Here are some standard 10" surrounds from Speakers Northwest they at least reference the cone diameter:
Speaker Size Surround OD Speaker Cone OD Surround ID Repair Kit Part#
10" Angle Attach 9 11/16" 7 5/8" 7 1/8" SWK10A
10" Flat Attach 9 3/4" 7 1/2" 7 1/8" SWK10F
Attachments
DSChamber
Well-Known Member
Yeah 7.5" cones are common.... your drivers would actually take the exact kit I am working with John on (well I am not sure on your OD)..
But his kit has the following dimensions..
OD - 9.5"
ID - 7"
Inside diameter of the roll - 7.5"
OD of roll - 9" (makes for a 3/4" roll)
So your drivers would "fit like a glove" with that kit if you glued the surrounds to the back.
I measured my cones for the 7" ID to see where the surround would sit... see the pic...
Basically the Inside diameter surround would sit on top of the second "circle", then add a 1/4" for overlap which brings me up to the first "circle" that is where the 3/4" roll starts, so basically the piece of cone between the first "circle" and the edge would be under the roll (if not trimmed off)...
I hear ya on not trimming anything, I would never be able to get it trimmed exactly perfect all the way round, even using the "circle" as a guide...
To have a perfect matching surround replacement I would need a OD of 9.63" and an ID of 7.5" (1/4" overlap on both sides)...if someone can find me that surround somewhere I would really appreciate it!
But his kit has the following dimensions..
OD - 9.5"
ID - 7"
Inside diameter of the roll - 7.5"
OD of roll - 9" (makes for a 3/4" roll)
So your drivers would "fit like a glove" with that kit if you glued the surrounds to the back.
I measured my cones for the 7" ID to see where the surround would sit... see the pic...
Basically the Inside diameter surround would sit on top of the second "circle", then add a 1/4" for overlap which brings me up to the first "circle" that is where the 3/4" roll starts, so basically the piece of cone between the first "circle" and the edge would be under the roll (if not trimmed off)...
I hear ya on not trimming anything, I would never be able to get it trimmed exactly perfect all the way round, even using the "circle" as a guide...
To have a perfect matching surround replacement I would need a OD of 9.63" and an ID of 7.5" (1/4" overlap on both sides)...if someone can find me that surround somewhere I would really appreciate it!
grillebilly
Empty Head
looks like you have been getting a lot of info on re-foaming woofers. One post mentioned ReEdger, he helped me out and knows what you need (and can supply it). He suggested that the coil be shimmed when re-foaming and I took his advice. It is guaranteed a better job IMO. It is no big deal cutting the dust cap with the proper tool. I used a razor knife that uses the "break away" razor ends. Most people I got advice from said don't bother to shim, but every professional said to do so.
I would suggest you contact ReEdger, he was fair and very helpful.
I would suggest you contact ReEdger, he was fair and very helpful.
terra1
Addicted Member
This is going beyond cutting the dust cap. Now it sounds like he is being told to cut and trim the cone itself.
***
Also will the new recommendation of 9.5" diameter give you enough coverage to glue to the frame? You originally said the old surround was 9 5/8".
9.5" would be 9 4/8" so you are losing an 1/8" in diameter of the surround to reach the frame.
***
Check this thread
You might PM Unican_Eric to see how they did the refoam on his Optimus T120. He's in Canada also.
http://www.audiokarma.org/forums/showthread.php?t=150573
DSChamber
Well-Known Member
Hey Terra.... yeah I remeasured my OD again, this time more accurately and it maybe 1/16" over 9 1/2"...so really 9 9/16" ... so that's only 1/32" in the difference on either side of the frame which is hardly going to make a difference. 9 1/2" will work fine with 1/32" "wiggle room"
terra1
Addicted Member
It's up to you whether you decided to trim the cone. It is something irreversible, which makes me feel uneasy. Let alone trying to cut evenly and avoid tearing. Keep in mind the foam is mostly to keep the cone in alignment and provide flexibility as it moves in and out. With the focus on all these measurements we may be losing sight of the goal.
If you try to place one of the surrounds as I mentioned on top of the cone. For example a 7 5/8" inner roll would only be 3/8" smaller than an 8" cone. 3/8" = 6/16" So the cone would extend past the inner roll around by 3/16" underneath.
So can I assume the seller discourages that and says that would create a problem with the sound?
But I would still check the thread I mentioned to see what they did. If the person who refoamed their T120 can provide their source or if they had to do any cutting.
DSChamber
Well-Known Member
Thanks... I did get a reply from Unican_Eric and he will check with the tech that refoamed his T120s as to where he got the surrounds..
I am also waiting on a reply from ReEdger... he did get back to me wanting to know the measurements.. I gave him those.
Time will tell if I get the right ones or not...
I am also waiting on a reply from ReEdger... he did get back to me wanting to know the measurements.. I gave him those.
Time will tell if I get the right ones or not...
DSChamber
Well-Known Member
Just thought I give you guys an update, you never know, maybe it will help someone in the future..
ReEdger (aka Gene) was a huge help to me in getting these woofers re-foamed. He had a look in his inventory and it is true, these woofers out of the T120's does not have a "normal" size cone for a typical 10" driver. So we had to improvise. I would like to take this moment to give Gene a big shout out, great person to deal with!!! I will be doing repeat business!!
He sent me a set of surrounds which I had to "cut down" in order to make it work.... never had to cut my cones at all...
Basically I cut the surround he sent me (I think it was a surround for an 11" driver, Gene if you read this maybe you can chime in) and fit it on the cone, then where it overlapped I cut off the excess. Once I trimmed it a little here and there to make it almost perfect, it was on to the normal re-foaming procedure. I totally recommend shimming the voice coil, I had to do it in my case regardless as the surround wasn't a "factory replacement" and there was no way to "eyeball" it place.... SHIM SHIM SHIM.... that's all I can say, don't feel bad about cutting into that nice dust cap, yer going to put a new one on anyway
You can see where the two edges meet, but this doesn't affect the sound at all.... it won't win any "beauty contests" and I could have probably been more tidy with the glue around the edge, but my T120's are rocking again.
I think the bass actually sounds better, if that is possible.....to me to sounds tighter and more "snappy" if that is even a way to describe bass reproduction, lol,... a side by side comparision of the speaker with the new surround and the one with the factory sound was clear cut, new surround = better bass reproduction (at least to my ears), old surround = "muddy" bass reproduction....
I was shocked actually that the surround on the driver that didn't fail was simply ready to "self destruct"... visually it looked fine, and sure it worked, but since Gene sent me two surrounds and from my side by side results I had to replace the other surround. By simply pinching the roll and pulling ever so slightly it gave way and crumbled...
The second surround install went better than the first (since the first was literally my first ever re-foam attempt), not so much technically, just more tidy (learned a few things from the first install )
Now I am a pro... lol... not likely, far from it... but it has opened my eyes to speakers I see with rotted surrounds... I won't be so quick to pass on these going forward!! I want to refoam all my drivers
Total time to re-foam one of these was probably an hour... then of course 24 hours of drying time...
What I started with..
The end result...the line where the "cuts" meets is actually mostly the line from the fine tip black marker I used to mark the overlap, the actual gap between the two is less than 1/32" , it's practically touching.
ReEdger (aka Gene) was a huge help to me in getting these woofers re-foamed. He had a look in his inventory and it is true, these woofers out of the T120's does not have a "normal" size cone for a typical 10" driver. So we had to improvise. I would like to take this moment to give Gene a big shout out, great person to deal with!!! I will be doing repeat business!!
He sent me a set of surrounds which I had to "cut down" in order to make it work.... never had to cut my cones at all...
Basically I cut the surround he sent me (I think it was a surround for an 11" driver, Gene if you read this maybe you can chime in) and fit it on the cone, then where it overlapped I cut off the excess. Once I trimmed it a little here and there to make it almost perfect, it was on to the normal re-foaming procedure. I totally recommend shimming the voice coil, I had to do it in my case regardless as the surround wasn't a "factory replacement" and there was no way to "eyeball" it place.... SHIM SHIM SHIM.... that's all I can say, don't feel bad about cutting into that nice dust cap, yer going to put a new one on anyway
You can see where the two edges meet, but this doesn't affect the sound at all.... it won't win any "beauty contests" and I could have probably been more tidy with the glue around the edge, but my T120's are rocking again.
I think the bass actually sounds better, if that is possible.....to me to sounds tighter and more "snappy" if that is even a way to describe bass reproduction, lol,... a side by side comparision of the speaker with the new surround and the one with the factory sound was clear cut, new surround = better bass reproduction (at least to my ears), old surround = "muddy" bass reproduction....
I was shocked actually that the surround on the driver that didn't fail was simply ready to "self destruct"... visually it looked fine, and sure it worked, but since Gene sent me two surrounds and from my side by side results I had to replace the other surround. By simply pinching the roll and pulling ever so slightly it gave way and crumbled...
The second surround install went better than the first (since the first was literally my first ever re-foam attempt), not so much technically, just more tidy (learned a few things from the first install
)Now I am a pro... lol... not likely, far from it... but it has opened my eyes to speakers I see with rotted surrounds... I won't be so quick to pass on these going forward!! I want to refoam all my drivers
Total time to re-foam one of these was probably an hour... then of course 24 hours of drying time...
What I started with..
The end result...the line where the "cuts" meets is actually mostly the line from the fine tip black marker I used to mark the overlap, the actual gap between the two is less than 1/32" , it's practically touching.
loose ends
Well-Known Member
Actually I have 4 of these woofers to refoam now and have done 8 in the past month for the same customer. I also did all his mids and new caps in all his crossovers. Now, I do a lot of speakers. And over the years the numbers have to be way up there.
These are hard speakers to do and don't let anyone tell you otherwise. If you can do these you can do any speakers. Don't pay attention to the outer diameter, it will have to be trimmed. Pay attention to the roll measurement and inner lip measurement. Angled attachment. I have to trim 1/8" from the outside of the surround all the way around. I don't shim or believe in it for 2 reasons. First all you need is one piece of dirt to ruin your job and second some speakers the dust cap is part of the sound.
The voice coils have very little clearance so I use (as I always do) a 30hz tone.
With the drivers I'm doing for him now and the ones already done I know he has a full set of extras. And possibly a set of recapped crossovers. I can email him to see if he wants to part with any. Just let me know.
These are hard speakers to do and don't let anyone tell you otherwise. If you can do these you can do any speakers. Don't pay attention to the outer diameter, it will have to be trimmed. Pay attention to the roll measurement and inner lip measurement. Angled attachment. I have to trim 1/8" from the outside of the surround all the way around. I don't shim or believe in it for 2 reasons. First all you need is one piece of dirt to ruin your job and second some speakers the dust cap is part of the sound.
The voice coils have very little clearance so I use (as I always do) a 30hz tone.
With the drivers I'm doing for him now and the ones already done I know he has a full set of extras. And possibly a set of recapped crossovers. I can email him to see if he wants to part with any. Just let me know.
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