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Ideas for JBL LE14A woofers w/ Lansaloy surrounds

What would you do with LE14A woofers with hardened Lansaloy™ surrounds ?

  • Refoam (but not recone).

    Votes: 25 80.6%

  • Refoam and recone.

    Votes: 2 6.5%

  • Apply DOT3 brake fluid carefully.

    Votes: 4 12.9%

  • Nothing. High Fs and low Xmax never bothered me anyway.

    Votes: 0 0.0%
  • Total voters
    31
GoldSounds

GoldSounds

Active Member
So I picked up a pair of JBL C53 Libras over the weekend. Driver complement is LE20 tweeters and LE14A woofers with LX-8 crossovers. Good news is that all the drivers work. However, the Lansaloy surrounds on the woofers has gotten still with age. I have read (particularly on the Lansing Heritage boards) that you can apply a small amount of DOT 3 brake fluid to the surrounds to at least temporarily make them more compliant. I have also heard many complaints saying that this may/will stain the white cones. I am not sure, but I believe that the surrounds may have been replaced or treated before; I can see some glue or other coloration but I'm not sure if it's original or not (see pictures).

My questions is: what are the risks and benefits of using the DOT3 (or refoaming) on the surrounds? I am not sure what to do because on the one hand, brake fluid is cheap, simple and keeps the surround original (and as such possibly retains resale value). On the other hand, refoaming is more permanent and will at least restore xmax. However, I have heard that this may change it's Fs, in addition to changing the driver's appearance and possibly lowering it's resale value. A third option is to do a full recone, which is apparently the only solution that Harman International endorses, but seems to be a waste of a perfectly good cone and spider. Ideally, if there is some magic solution that I can apply that will perminently restore them (think that AR/KLH woofer doping stuff), I'd gladly seek it out.

Anyone who's had experience with any of the above procedures, please advise.

Pics of underside of LE14A driver:



 
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I refoamed mine, after a trial with the brake fluid. I doubt many here will find brake fluid to be the miracle cure for the issue, and would guess most have opted to refoam eventually. There's no way it will restore the original suppleness to the Lansalloy, so if you want to use it as a stopgap to enjoy a preview of what fresh surrounds will do, go ahead. but my money says, you'll pop for new foam eventually.
 
I seriously doubt JBL did such a sloppy job of gluing that surround.
Also I've been told that Lansaloy replacements were still available up till the late 80's, so yours might be relatively new.
Alas they have stiffened and can be softened up nicely with the Dot 3.
Applied diligently with a small camel hair brush has so far worked for me on the LE15a.
 
The old yellow surrounds, from my personal experience, if you get real luck to un-stiffen the surrounds typically hit anywhere near their original driver parameters. The hard facts in my experience is to remove the old stiff surrounds, clean them up well and install new surrounds. At least this way they will be much closer a product to make a proper enclosure. They usually work well in 3.75"~4.25" cubic footeage.
DC
 
It's sounds like one way or another I'll eventually end up refoaming them. Is there any foam that looks original, or is standard black my only option?
 
I've been seeing listings for white surrounds for these on ebay. They're very white. Maybe too white. Unsure.
 
GoldSounds said:
Looks like you might need to use the rumble filter on your turntable.:D

That said, the range of movement of the cone and surround is impressive.
Click to expand...
Actually I was pushing the passive radiator.
My point was to illustrate the viability of using DOT3 on Lansaloy surrounds, specifically ones that are simply "stiff", without rips tears or cracks.

However I would not recommend this process to someone impatient or without a confident steady hand or to someone who thinks it will fix cracked surrounds.
 
BMWCCA said:
Just curios, what's your basis for comparison
Click to expand...
They sound "superb" as in smoother, deeper, faster and more articulate than before the DOT3 or do you mean like compared to a Realistic Mach I or something even better?
 
tubed said:
They sound "superb" as in smoother, deeper, faster and more articulate than before the DOT3 or do you mean like compared to a Realistic Mach I or something even better?
Click to expand...
It's great that the DOT3 improved them, but I guess I was more wondering if anyone had the chance to compare the DOT3 treatment with a pair with replacement foam surrounds, and how they compared. :dunno:
 
I'm pretty confident that compared to the skinny-rolled replacement surrounds these seemingly healthy treated Lansaloys would compare favorably, especially since they are the surrounds used in the design the speaker system, as opposed to the replacements.
But we'll probably never know for sure unless you bring your pair over.
 
That's part of the reason why I am hesitant to just outright refoam them; I figure the mass and mechanical compliance of the surrounds plays into the T/S parameters. The issue is that these drivers are around 50 years old (at least mine are) and so I'll never be quite sure if I've applied enough DOT3 or if any new foam inhibiting the driver from performing properly.

I might get up the courage (and steady hand) to try the DOT3 tonight, simply because the curiosity to see how well it works is overwhelming me.
 
Well, I tried the DOT3 treatment and so far I've noticed an obvious improvement. I applied it only to the front side of the surround -since I didn't trust myself not to accidentally remove some of the paint off the backside of the driver- and I applied it sparingly as to not stain the cone. Visually, the driver looks the same as before, except for the texture of the surround looking perhaps a little "puffier"; no stains or coloration. The surround it much softer now, and I can move the cone my hand with minimal resistance, and with much greater excursion. I suspect that my judicious and cautious application of the DOT3 has probably left the drivers less than completely restored to original specs, but still closer nonetheless. I reinstalled them into their cabinets and had a listen. I must say that I am impressed. Perhaps there could be a little more deep bass, but the bass that is present is very articulate, fast and tight. I haven't even rebuilt the crossovers yet but the imaging is impressive. I still may opt to refoam in the near future, but I think that I'm going to gain some familiarity with these speakers as they are now first.
 
Well GoldSounds hopefully your drivers will end up golden.
However I would not yet be playing music through them just yet.
What causes cracking of the brittle Lansaloys is the stiffness and something has to give if they are not completely treated(ymmv).
I'd do a series of light applications with generous soaking times in between apps. so as not to have any possible overflow/seepage.
Be patient, think days not hours:)
 
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