Jbl Sub1500 15" Subwoofer 4 Ohm

[baldrick]

The first of my SUB1500 is alive

[Mostlydiy]

Very beautiful Baldrick! If the cabs are DIY Im very impressed

/Mostly

[John in Ecuador]

Ok, I've had a pair of SUB1500 since 2004. One got pushed a bit too hard a few years back. And it was either the voice coil hitting the cone or rubbing on the sides.
turning it on its back worked for awhile. Then started the rubbing noise again. Then I noticed the spider had come loose. So I re-glued it, and all was good again. And was able to use it in the proper vertical orientation. That lasted a year or so.
Started rubbing again. So I cutout the dust cap today to have a look, rub marks in two places.
Any thoughts on how to fix it?

[1audiohack]

Hi John;

Welcome to Lansing Heritage.

I can't see in the pic where the rub points are.

I have a 2123 that has a rub that I haven't been able to get it out despite having cut off the cap and left a shim sleeve in it for months.

Is the spider still even and flat?

Barry.

[Earl K]

Heather James had a good tip on saving a 112a cone that had shifted slightly ( causing VC rubbing ).

It went like this;

The solution involved inserting proper/tight fitting shims ( in at least the 4 points of a compass ) in the gap between center pole and VC former ( you are ready to proceed since you've already removed the dust-cap > you just need to create some tough plastic shims ) / then loosening-shifting the spider ever so slightly ( by chemical means ) through painting the spider with MEK ( methyl-ethyl-ketone ) and allowing the softened spider to re-harden in a slightly altered position ( accomplished as the MEK evaporates and the spider re-hardens ).

Too much MEK will dissolve glues ( so apply where there aren't any glues ) .

Good Luck!

[Mr. Widget]

Will MEK loosen cyanoacrylate adhesives? I believe JBL used some cataylised industrial CA glues on these drivers' spiders. There were issues with some not getting the proper catalyst and those had spider adhesive failure, but most are seriously glued. I believe Edgewound has repaired some and may be able to shed light here.


Widget

[Earl K]

Will MEK loosen cyanoacrylate adhesives? I believe JBL used some cataylised industrial CA glues on these drivers' spiders. There were issues with some not getting the proper catalyst and those had spider adhesive failure, but most are seriously glued. I believe Edgewound has repaired some and may be able to shed light here.

Widget

I believe that Heather's fix mostly involved "reforming the spider" // not actually moving the original glue points .

But I don't really know // though I do have a hand-full of various le10 types that all need some sort of remedial centering treatment such as this ( I've been waiting for warmer weather before proceeding ) .

[bubbleboy76]

If I remember correctly, the wrongly manufactured SUB1500 woofers had orange glue on the spider.
I think it were those that were sold out cheaply on parts-express.

[John in Ecuador]

Hi John;

Welcome to Lansing Heritage.

I can't see in the pic where the rub points are.

I have a 2123 that has a rub that I haven't been able to get it out despite having cut off the cap and left a shim sleeve in it for months.

Is the spider still even and flat?

Barry.

One rub spot is right at the top of the pic, a strip much darker in color.

When I noticed the spider had come loose, it was not completely loose. About 1/3 of the circumference was still connected. I re-glued it with liquid silicone, applying a continuous bead. Then weighed it down for 24 hrs. That was at least a year ago.

A few days after I cut off the cap, last week, I looked closer and noticed the two rub marks were in the first inch from the front edge. I grabbed that edge and pulled the cone assembly forward. The pole piece? in the center is now behind the rub marks. Seems to be working properly again. I have not cranked up the volume excessively since.
I might turn it off and try shimming it.

One thing I forgot to mention. My original thoughts of the problem, is the VC hitting the back of the driver. First happened when I increased the sub volume in the AVRs speaker settings. It was then doing it at even low volumes.
so I removed the driver and bounced a few times on the floor, reinstalled it and left the box with the driver facing up. Was working again w/o any problems. For awhile.
When I removed it again, is when I saw the spider had come loose. Glued it.
Well, if I turn up the volume too much it will still sound like the VC hitting.
Normal listening levels, not a problem.

[John in Ecuador]

It would seem the sub driver problem has been rectified. Last night I played Helene Fischer's English Ones album with the VOX player's EQ set with a hump in the bass range. And no problems, kept up with the other 1500.
90dB at the seat