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Standingwave3
03-07-2016, 01:30 AM
This is my first post since joining this group. I have a pair of these speakers which have been hardly used in the 25 years or so since purchased. The foam is gone on both woofers and I want to re-foam myself. It would be the first time for me to try re-foaming. I,have been warned off this project by a number of people who say the tolerances on the voice coil,are too tight and make the job very difficult compared to other brands of speakers.Are they correct in this advice?

Odd
03-07-2016, 03:27 AM
It's not very difficult to do it yourself.

Buy refoam kit from
Rick Cobb
rcobb@tampabay.rr.com

and follow his instructions.
Resurround Step-by-step (http://www.audioheritage.org/vbulletin/showthread.php?469-Resurround-Step-by-step)

Standingwave3
03-07-2016, 04:57 AM
It's not very difficult to do it yourself.

Buy refoam kit from
Rick Cobb
rcobb@tampabay.rr.com

and follow his instructions.
Resurround Step-by-step (http://www.audioheritage.org/vbulletin/showthread.php?469-Resurround-Step-by-step)


Yes I have already been in touch with Rick Cobb. However recently I have been advised that JBL speakers are built to very high tolerances that make the job much more difficult than for other brands. That is what I was really asking about...is it especially tricky to do with A JBL 4410 Studio Monitor.

Odd
03-07-2016, 06:22 AM
No

Chris Brown
03-07-2016, 06:50 AM
Voice coil gaps are usually more narrow on a JBL, but not to the point of not being able to refoam them yourself. Just make sure to have a spare receiver or similar available so that you can test each woofer using the ~30hz test tone. Some people like to skip that step and just do it by feel. That is really where you might run into problems.

mech986
03-10-2016, 07:51 PM
If you are really concerned, get some additional dustcaps that are slightly larger as spares. Clean off all old foam from the cone back and the frame.

If you are very careful, you can cut the original caps near the glue lines about 95% of the way around. Then flip the cap over but do not detach it. Shim the voice coil evenly with thin card stock paper to center the voice coil in place. Then proceed with gluing the foam to the back of the cone, let dry, then glue to the frame. Once dried, then you can pull the shims and check for clearance. If ok, then you can reposition the dust cap and reglue with black glue to cover the cut and old glue line, or alternatively, remove the cap entirely, then glue on the slightly larger cap over the original dust cap area and line with new black glue.

AlFromRochester
06-08-2016, 06:29 AM
Actually I am concerned about this, but for a different reason.

I've refoamed a few pairs of woofers by now, and have done both the shim and the 15 Hz hand-centering methods. I have never had any significant problems. But gluing a surround to the back of a cone and getting it centered, as on these woofers, sure seems like a tricky and treacherous operation.

I have decided to use the shim method for this reason. If I'm going to be monkeying around back there, stretching the surround over the circumference of the cone, and tearing it off where the glue prematurely grabs it, as I'm sure it will, I think I want the voice coil anchored just so it doesn't get damaged.

Of course I would be very happy to hear from people who have done this job to this woofer, and who maybe would like to share some observations and advice on the procedure.

SEAWOLF97
06-08-2016, 06:59 AM
Of course I would be very happy to hear from people who have done this job to this woofer, and who maybe would like to share some observations and advice on the procedure.

I've done it for my 4410's , no biggie. (and I have no special skills/talent)

As long as you make it a 2 step process. glue down the foam to the cone FIRST . Easy to center it.

Wait till dry.

2nd step ...glue to frame. I center by feel , having done the test tones & the shim method , they are not needed FOR ME. As long as you test In & Out on both the X & Y axis while the glue is setting up and then clamp down when happy ... you should be successful. NOT rocket science.

AlFromRochester
06-08-2016, 07:18 AM
I've done it for my 4410's , no biggie. (and I have no special skills/talent)

As long as you make it a 2 step process. glue down the foam to the cone FIRST . Easy to center it.



Now, you said "glue down" to the cone. Are you doing that with the driver pointing up and gluing the surround to the front of the cone, or are you doing it with the driver pointing down and gluing the surround to the back of the cone, as regulation?

SEAWOLF97
06-08-2016, 07:36 AM
Now, you said "glue down" to the cone. Are you doing that with the driver pointing up and gluing the surround to the front of the cone, or are you doing it with the driver pointing down and gluing the surround to the back of the cone, as regulation?

driver facing UP ..glue to it's back.

the back is so easy that I have trouble gluing to face on other drivers anymore. Once glue is setting up, put some small weight on center of cone to make pressure between cone and surround. I use a salt shaker.

AlFromRochester
06-08-2016, 07:59 AM
driver facing UP ..glue to it's back.

the back is so easy that I have trouble gluing to face on other drivers anymore. Once glue is setting up, put some small weight on center of cone to make pressure between cone and surround. I use a salt shaker.

Well son of a gun.

SEAWOLF97
06-08-2016, 10:07 AM
I've done it for my 4410's , no biggie. (and I have no special skills/talent)

As long as you make it a 2 step process. glue down the foam to the cone FIRST . Easy to center it.

Wait till dry.

2nd step ...glue to frame. I center by feel , having done the test tones & the shim method , they are not needed FOR ME. As long as you test In & Out on both the X & Y axis while the glue is setting up and then clamp down when happy ... you should be successful. NOT rocket science.

The exception (for me) is the LE14-H1. It has a ledge/groove that the foam exactly fits into , so NO adjustment room.

The foam HAS to be glued to the basket first and then the centering adjustment when gluing to the rear of the cone.