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View Full Version : JBL 2231a Woofer refoam suggestions/thoughts



brabus420
10-21-2017, 11:22 AM
I have a pair of JBL 2231a woofers with rotted foam. I've done a refoam on some proac speakers but have no experience with JBL. I have some questions.

1. Recommendation on where to buy refoam kit. I've checked ebay and google and there seems to be quite a few vendors. Looking for high quailty foam
2. Shim or not to shim? I was able to not shim on my proac and they turned out great. But I read there may be a piece of foam that may have rotted underneath the dustcap that should be cleaned out and replaced. Also, has anyone tried carefully cutting out and reusing the same dust cap to 'keep it original"?
3. Any other advice?

These came from a pair of 4333a speakers and I'm starting the process of refurbishing them.

Thanks!

Earl K
10-21-2017, 02:38 PM
The products from this fellow mentioned ( within this thread Re-Surround Step-by-Step (http://www.audioheritage.org/vbulletin/showthread.php?469-Resurround-Step-by-step) ) come very highly recommended .

:)

RMC
10-22-2017, 10:52 AM
Hi Brabus,

I'd rather shim to make sure the voice coil and cone stay in the right in place during work on surround, and especially if you're going to open and keep the dustcap.

RE the possibly rotten foam piece under the dustcap. I don't own the 2231 so can't tell you for sure, but maybe you're referring to a possible driver back vent foam that can be accessed partially from under the dustcap? Is there a driver back vent on your 2231? If so let me know I may have a few ideas for you since I had to do that on my 2214H and its a big job to clean this mess nicely. Patience and meticulous work...

I have cut open about 90% (not removed) and re-used the same duscaps to keep things original as you say. I use a scalpel (same as surgeons use) to cut almost all around, except I stop cutting just before I touch the wires which you don't want to damage... The cutting line is made just above the black glue line (barely touching it) holding the dustcap. Your cutter must be as horizontal as possible while cutting not too deep to avoid damaging voice coil. My original caps were thick and tough, so I started with a first pass half-inch long and did a second pass in the SAME groove and at the third pass I was through. From there on its easier since you have a starting point. But remember: slowly, HORIZONTALLY and stop just before cutting the wires...

Then you can lift slowly and delicately the dustcap and make it hold in place vertically or so with a piece of tape from dustcap to driver frame to clean-up inside driver or from dustcap to cone when shims are in for installing new surround (not too sticky tape to be removed easily without damage, I use 3M blue painter's tape made to be removed easily and barely press on it to stick to cap and cone ).

I don't know if on the 2231 the surround is glued on the front or back side of the cone (2214 was on back side, little more difficult), however if on the back side of cone, then remember your cut open dustcap will be hanging downwards, when the driver is face down, and may be damaged if you move the driver like turning it to glue around back side of cone. So in such a case remember to tape the dustcap NOT vertically (maybe not horizontally either because of shims in place) but rather taped at an angle like 45į so it doesn't touch working surface...

After I cleaned the foam mess inside the driver, I used copier paper strips and passed them many times inside the gap around voice coil in a circular motion to clean the dirt, dust and foam that made its way there. I used many "home made" tools, let me know if you need suggestions.

Richard

brabus420
10-22-2017, 10:10 PM
Thanks for the responses. I took some pictures of one of the woofers so people can see. It's good to know that you can reglue the original dustcaps as I wanted to keep them original as possible. I'll have to pick up an exacto knife as I've been used razor blades in the past and they are a little harder to control and I definitely don't want to accidentally cut (I knew I should have kept my biology dissection kit from college! =) ) And good idea about making sure to make sure the dustcap doesnt dangle as I will have to probably flip the speaker over since the foam attaches from the backside.

Any suggestions on where to buy the re-edge kit from? Here were some options I found:

https://www.ebay.com/itm/JBL-2235-2235H-2231A-15-Woofer-Foam-Speaker-Repair-Kit-w-Shims-Dust-Caps-/150413207956?epid=1231617928&hash=item2305536994:g:OtYAAOxy4YdTTYz3

https://www.ebay.com/itm/JBL-SPEAKER-15-135A-136A-2231-2232-2234-2235-Foam-Repair-Kit-/201970792832?hash=item2f0665b980:g:12cAAMXQeKNTOxB v

https://www.ebay.com/itm/2-JBL-15-Speaker-Foam-Repair-Kit-2215H-2215J-2231A-4343B-2LE15-/292208417913?hash=item4408fa9c79:g:MsAAAOSw0axZhOh u

TIA

RMC
10-23-2017, 10:24 AM
Hi brabus,

I already gave you a suggestion in post # 3 on how to hold the dustcap when putting the woofer face down in order to put glue on the back side of cone.

As for where to buy re-foam kits, can't help you with e-bay, I don't purchase on that site because too many lies from many vendors and "fly by nights". I purchase from companies who have a street address like Speaker Exchange, Simply Speakers, etc.

Richard

grumpy
10-23-2017, 11:01 AM
Iíve personally used this sellerís surround products on a number of projects (successfully).
Happy to recommend, without compensation or any other association.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F17 2504104168 (https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F17 2504104168)

RMC
10-23-2017, 03:40 PM
HI Grumpy,

Thanks for giving me back a little faith... in a world of BS and cheating for many vendors on the Web. Looney tunes isn't that commonly known as Rick Cobb? Thanks,

Richard

grumpy
10-23-2017, 04:22 PM
Yes. Note that there are some JBL woofer models (e.g., 128H -if- I recall correctly) that used more than one cone diameter during their production run, so Rick might ask for a cone diameter measurement... this is a good thing.

brabus420
10-28-2017, 08:53 AM
Iíve personally used this sellerís surround products on a number of projects (successfully).
Happy to recommend, without compensation or any other association.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F17 2504104168 (https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F17 2504104168)


Did you cut the dustcap to shim when you refoamed? This ebay seller mentions no dustcap cutting required. Thanks

grumpy
10-28-2017, 03:47 PM
I have not (so far) re-surrounded a driver that has required the removal of the dust cap. I’m not saying that it’s not ever necessary, just that if there are not other issues than surround deterioration, the 30Hz tone method has been adequate for me. There was one case where an adjustment was required late in the process (old 116 driver), so that re-surround may have benefited from shims, but may also have ruined the concave dustcap and I was hoping to maintain the original look. I’m guessing there were spider issues that could have been addressed by other means (and which shimming would not have addressed).

At some point, after several resurrounds, a driver’s cone integrity may become degraded to the point that a full recone is in order... I just finished re-surrounding a 2214H driver today that has nearly reached that stage :crying:

bldozier
10-28-2017, 04:52 PM
grumpy
isn't it necessary to ordinarily shim the cone for height when your doing a recone your saying the speakers you've done
have not needed to be shimmed, I'm asking only since i've seen you mention not removing the dust caps.

grumpy
10-28-2017, 06:29 PM
Well, I wasnít discussing a recone.

A recone ďkitĒ that is not preassembled would indeed require additional care and materials (and knowledge) even beyond voicecoil shims. Thatís work Iíd hand off to a professional if it was a valuable driver I cared about. Maybe experiment with an aftermarket kit and be prepared to rip it back out as part of a learning experience?

I avoid doing drywall and stucco too, although iíve tried both :)

RMC
10-29-2017, 02:50 PM
Hi brabus,

If you have foam rot Inside the back vent you'll need to cut the dustcap to be able to remove all that rotten foam from Inside the driver (which Grumpy may not have had to do). You can't clean it all without doing it. Go back to my post # 3 if this is the case. And I would still shim before installing new foam, specially if the dustcap is already cut open for cleaning purposes.

Richard

grumpy
10-29-2017, 04:45 PM
No disagreement here :)