FYI: How I fixed my Mal-X 21's

As you can see, the flux ring is no longer vibrating. (YAY)



Step 1:
VERY very very carefully remove the cone and spider with a small flathead screwdriver without damaging them; this takes about 2-3 hours... takes patience borderlining on insanity, no less.

Step 2:
Then use the wood handle of a painters fan brush (any non-magnetic substance really) to confirm the loosest side of the ring.

Step 3:
Grab your superglue and a toothpick.

Step 4:
Insert the toothpick into the top of the ring on an angle and drop drips of superglue into the crevasse via the toothpick.

Be VERY very very careful not to get any excess glue on the gap walls, you only have 0.25mm or so of motor clearance. (Or the toothpick stuck)

Step 5:
Reattach cone and spider with more glue, make sure it is centered to the n-th degree +-0.5mm

Your done.

These things are far too good at generating infrasound to just throw them away; not only that, but they are almost at expensive as LMS-18's!!!

Without the repair they make nasty super-annoying metallic noise, similar to that of bottoming or rub; but it's niether, it's actually Lenz's Law of EMF backforce vibrating the loose ring around, made worse by coil heat, over time.

I'm just happy with the thought of getting all 17 of my subwoofers back up and running again... this is gonna take years, ohhh......

Right now I'm only running 5 subwoofers, by summer I should have 9 going (maybe); I've changed my mind on box designs, multiple singular sealed scattered throughout the room is the way to go.

Were talkin micro-liters of glue here, barely enough to fit under your fingernail.
No idea what it's rated for, but it seems to be holding so far.

The rest of the glue is far enough away from heat source that it doesn't really matter.

I have 4 Dayton Pro's, 2 SDX-15's, 8 Mal-X's, 2 Mal-X 21's and 1 LMS-18

Dayton's are in a 15x19x19, SDX in a 20x20x21, LMS in 23x23x24.5

I haven't tried IB or Horn configs yet, maybe one day I will, but for now I think I'm going to keep it simple and go sealed for all of them.

The Mal's will all be 23x23x24.5 as well.

My system has 30 to 200hz well covered already, so I was thinking of making them mostly infrasonic generators at no higher than 35hz...
put all that surface area to use where it is needed most, and avoid being obnoxious to the health of my eardrums or drowning out the rest of the music with excessively bloated bass. Or at least, that's the idea we'll see...

I didn't take any photo's, but you can watch the video in 1080p mode @ 50 seconds in you can clearly see the flux ring.

If you count the number of slugs from the top of the basket, the flux ring is attached to the inside of the second black metal slug (the one directly above the pair of ferrite slugs), it is a 3" metal ring inside the gap.
You can't miss it, it's the only thing not painted black or made of ferrite.


It shouldn't need more than a hairline amount of glue, just enough to fix it in place, and not decrease the gap width.

The hardest part was actually not puncturing the surround with whatever sharp object your using to deattach it with.

The second hardest part was recentering the coil without rub, that takes pure wizard-like skills, I'd hate to have to work it a woofer factory doing this all day they must have a lot of throwaways; you have to be damn sure it's good, no margin for error.

I didn't capture the reassembly, just take your time... measure 5 times and glue once

I've fed the thing every watt the EP4000 has got and the glue is still holding after all this time. She hasn't popped yet. I don't think she's gonna.


Obviously the LMS is the star of the show

I couldn't see how shims would help here because at some point you have to pull them out without moving the spider that overlays on top of it, before gluing it down and that would probably make things worse because of the increased likelyhood of accidental movement.