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vettedrummer
01-24-2008, 12:34 AM
Hello everyone, just a quick question. Is it true that on the LE14A and perhaps the "C" too that the surround foam goes over the paper cone and not under like on most of the other JBL speakers? Not sure where I heard that perhaps even here. Does anyone know for sure? Cheers, Frank

johnaec
01-24-2008, 05:56 AM
That's correct.

John

Earl K
01-24-2008, 06:12 AM
Is it true that on the LE14A and perhaps the "C" too that the surround foam goes over the paper cone and not under like on most of the other JBL speakers?

- It's true that the original foam is attached to the front side of the cone .

- It's also true that a couple of regulars here, have attached aftermarket foam surrounds ( Ricks' ? ) to the front side ( as in the original ).

- Importantly ( IMHO ), these "refoamers" have not provided any proof that the voice-coil is still centered . They should have at least provided some close up pics of the spider / so that the rest of us could determine for ourselves if the spider looks flat ( rather than depressed or pulled out ) .
- I also notice that no-one, so far, has flipped the new foam over, ( 180°-reverse ) to match the original orientation of the half-roll ( the original lansaloy is an "innie vs the outie" of the new foam ) .

- From my perspective, it's still inconclusive as to which is the correct way ( gluing to front or back of cone ) .

<> EarlK

johnaec
01-24-2008, 07:16 AM
- I also notice that no-one so far, has flipped the new foam over 180° to match the original orientation of the half-roll ( the original lansaloy is an "innie vs the outie" of the new foam ) .As I recall, the original yellow lansaloy surrounds were concave, but when JBL later switched to black foam surrounds on the LE14's, while still mounted to the outside, the rolls were now convex.

John

Earl K
01-24-2008, 07:27 AM
As I recall, the original yellow lansaloy surrounds were concave, but when JBL later switched to black foam surrounds on the LE14's, while still mounted to the outside, the rolls were now convex.

- I've never seen an original black foam surround ( on a le14a or H ) attached to the front ( outside ) / they've all been attached to the backside of the cone ( at least that's how my le14H woofs' surrounds are attached ) .

- It's all semantics ( IMO ), I'd attach new surrounds to give the most level spider deflection ( as close to a straight line when the woofer is placed facing upwards ).

- Though I should mention, I wouldn't buy used le14s with the black foam attached to the front-side of the cone .


:)

89-300ce
01-24-2008, 07:57 AM
While we're talking LE14's, can this transducer be used in a down firing mode for sub use?

Thanks

Jorg

edgewound
01-24-2008, 08:14 AM
While we're talking LE14's, can this transducer be used in a down firing mode for sub use?

Thanks

Jorg

Not a good idea. The cone is rather heavy and gravity won't do it any favors.

Best in a verticle orientation.


As far as where the surround is mounted...the original location is the bst method.

If the spider is over fatigued and stretched, that should be replaced too.

With the scarcity of LE14(x) recone kits, that will be the preferred alternative for restoration. New surround, spider, and dust dome.

It's considerably more difficult than a refoam, but the results in many cases will be superior in performance due to voice coil positioning at rest.

I've rarely seen a fried LE14 4" voice coil....they are very robust, and should continue to last a long time....short of abusing them.

johnaec
01-24-2008, 12:56 PM
- I've never seen an original black foam surround ( on a le14a or H ) attached to the front ( outside ) / they've all been attached to the backside of the cone...In retrospect, I do believe you're correct. LE14A's with original black foam appear to have the surrounds glued to the back...

I do believe if replacing the original yellowed surrounds it still makes more sense to glue them to the front, as original, even though the roll is reversed.

John

Don C
01-24-2008, 04:28 PM
Although it doesn't sound like a very good idea to me, Fosgate did produce LE14H-1 based subwoofers (model FS400)with down facing woofers. I own a set. I don't know if there is any bad effects, because both I and the previous owner use them on their side, with the woofer facing sideways as usual.

brutal
01-24-2008, 06:44 PM
In retrospect, I do believe you're correct. LE14A's with original black foam appear to have the surrounds glued to the back...

I do believe if replacing the original yellowed surrounds it still makes more sense to glue them to the front, as original, even though the roll is reversed.

John

Cosmetically, it looks much nicer than leaving the old Lansalloy on the front cone edge, or peeling it off and leaving the yellow glue residue behind. I also had a little bit of the Auquaplas lift when I did mine.

jblsound
06-11-2008, 04:50 PM
I've just got a pair of foam surrounds for LE14As and doing a dry fit, it does appear that the surround fits better behind the cone. This is also the way one LE14C I bought years ago had the foam mounted.
Also tried it in the concave direction, and over the cone, just doesn't look quite right, too deep, compared to the old Lansalloy.

Zilch
06-11-2008, 05:56 PM
http://audioheritage.org/vbulletin/showthread.php?p=212380#post212380

shaansloan
11-29-2008, 10:55 AM
Cosmetically, it looks much nicer than leaving the old Lansalloy on the front cone edge, or peeling it off and leaving the yellow glue residue behind. I also had a little bit of the Auquaplas lift when I did mine.


I've just got a pair of foam surrounds for LE14As and doing a dry fit, it does appear that the surround fits better behind the cone. This is also the way one LE14C I bought years ago had the foam mounted.
Also tried it in the concave direction, and over the cone, just doesn't look quite right, too deep, compared to the old Lansalloy.

I am refoaming a pair of LE14's and I am facing the obvious dilema spoken of in this thread....I had substantial lifting of the Aquaplas while removing the old Lansaloy.....

Question....If I put the new foam on the rear of the cone as suggested for proper spider positioning, is there some coating I can use on the front to cover where the Aquaplas was lifted or is the Aquaplas still available....has anyone had any success using something for touch up?

BTW, these came out of these old "Barsilay" cabs I picked up...they have LE14's and LE20 and are built like custome end tables with swinging doors....kinda of a interesting old set to keep me busy piddling in the garage....

Thanks,Shaan

Earl K
11-29-2008, 11:34 AM
Hi Shaan,


I am refoaming a pair of LE14's and I am facing the obvious dilema spoken of in this thread....I had substantial lifting of the Aquaplas while removing the old Lansaloy.....

That's unfortunate, did you use anything to soften up the lansaloy before the removal process ? ( just curious, since I have a few old le14a beaters )


Question....If I put the new foam on the rear of the cone as suggested for proper spider positioning, is there some coating I can use on the front to cover where the Aquaplas was lifted or is the Aquaplas still available....has anyone had any success using something for touch up?

- Whichever method you choose ( glued behind or in-front ) , pick the position that offers the flattest line across the spider. Doing so will give the best positioning to the voice-coil relative to the top-plate ( gap ) .

- One can't buy white aquaplas to recoat the lifted areas .

- I would consider just painting the damaged areas with the appropriate product from a manufacturer like "Zinsser" . They make an oil-based product called "Cover-Stain" that is an interior/exterior Primer Sealer . This product was used to ggreat effect by past member Steve Gonzales . Do a search to see if my memory is correct ( FWIW, the posts may have been expunged/deleted ) .

<> cheers

shaansloan
11-29-2008, 03:14 PM
Hi Shaan,That's unfortunate, did you use anything to soften up the lansaloy before the removal process ? ( just curious, since I have a few old le14a beaters )..... Whichever method you choose ( glued behind or in-front ) , pick the position that offers the flattest line across the spider. Doing so will give the best positioning to the voice-coil relative to the top-plate ( gap )

Yes sir....I used some MEK like one of the threads suggested....I think the MEK unfortunately also loosened up the Aquaplas.....

Will do on the new foam.....I suppose if I can get away with putting on the front(if that is the flattest position for the spider, it wont be much of a problem.....

I'll let ya know how it goes.... thanks,Shaan

johnaec
11-29-2008, 03:23 PM
Wasn't the original white lansalloy surround on the original LE14A's mounted on the front of the cone anyway? In this case, I feel it totally acceptable, and possibly preferred, to put the new surrounds back in the original position on the front of the cones, even though the foam is now black. I even have 2 sitting here right now that were done that way, and though the color of the foam is different,specs should be closer than if mounted on the back sides. Am I missing something here?

John

speakerdave
11-29-2008, 04:28 PM
. . . . Am I missing something here?

John

I think Rick Cobb told us no one was making a foam now for front mounting, only for the back. Putting the available foam on the back would create some small amount of forward pressure against the spider. I've had sleepless nights, but not about this.

brutal
11-29-2008, 11:10 PM
The only thing I ever had the opportunity to speak to Rick about on the LE14A was the availability or use of a concave surround similar to the original Lansaloy. He advised his surround was intended for convex use facing out and applied to the front of the cone, and that their wasn't a large enough gap between the cone edge and basket to use the foam in a concave manner.

If a large amount of Aquaplas was pulled off then either too much, or too little, MEK was used and the removal process was too aggressive, or the Aquaplas to cone paper bond was already compromised. I was a slow and careful, applying MEK lightly with a Q-Tip, dampening the foam just enough to allow it to peel, and if it resisted too much, re-dampening it - but not to a point of saturation. I wouldn't have felt comfortable doing it without already having a good feel for how much MEK to use based on previous refoam jobs.

speakerdave
11-30-2008, 10:19 AM
. . . . If a large amount of Aquaplas was pulled off then either too much, or too little, MEK was used and the removal process was too aggressive, or the Aquaplas to cone paper bond was already compromised. I was a slow and careful, applying MEK lightly with a Q-Tip, dampening the foam just enough to allow it to peel, and if it resisted too much, re-dampening it - but not to a point of saturation. I wouldn't have felt comfortable doing it without already having a good feel for how much MEK to use based on previous refoam jobs.

What he said. The judicious amount of MEK leaves most of the aquaplas, loosens the glue and leaves the lansalloy strong enough to be pulled off in strips, sometimes using a little encouragement with a rounded exacto blade to assist the parting. I practiced on an LE10 that had other problems.

shaansloan
12-02-2008, 08:15 PM
If a large amount of Aquaplas was pulled off then either too much, or too little, MEK was used and the removal process was too aggressive, or the Aquaplas to cone paper bond was already compromised. I was a slow and careful, applying MEK lightly with a Q-Tip, dampening the foam just enough to allow it to peel, and if it resisted too much, re-dampening it - but not to a point of saturation. I wouldn't have felt comfortable doing it without already having a good feel for how much MEK to use based on previous refoam jobs.

Brutal I think you definately got it right here....too much MEK.....however it seemed with this pair the Lansaloy was almost permanently bonded to the Aquaplas and was extremely dry and brittle and breaking apart.....I tried to be as meticulous with this as I could.......I am sure I was over agressive with it.....but I wonder if there are some cases when it is just too brittle to remove without damaging the Aquaplas.....

I wont lose much sleep over this one either.......I think I will put TFOF and move on as long as much spider position is not too compromised....... these drivers go in Barsilay cabinets and the grill are not removeable so they cant really be seen anyway....

Thanks for the help.....

Shaan

herki the cat
02-10-2010, 04:10 AM
Not a good idea. The cone is rather heavy and gravity won't do it any favors. Best in a verticle orientation.

Well, not mounted in a verticle orientation continues over a long time to completely stretch the spider further out permanantly. I have seen four of each new-in-the-box ... Altec 515-B & JBL 2245 (?)18 inch speakers long-forgotten in storage, face -up in a dealer's back room, where the spiders had streched out a good 1/2 inch permanently. I got them for $100 each. I kept them face-down for many months until the spiders reformed perfectly flat. I am not sure it is safe to use MEK to soften the JBL phenolic spider; for one thing, there is a foam plug in the motor pole piece which reverts to gooy polyurethane eventualy & will creep in the voice coil gap. Gravity did play its part gently. New foam was required on the JBL's, and MEK did help on the Altec "gooped" surrounds.

cheers herki the cat

bldozier
06-28-2018, 10:48 AM
here are mine, one LE14 is much older then the other as seen from the pictorial, hopefully the surround will cover the lifted areas.

81607
81608
81609
81610