jbl 2432h driver =gap alignment?

[engineerjoe]

I upgraded my PA with better JBL 1.5" drivers and had the stock ones left laying here. I got an empty JBL box and decided to fill it and make a monitor. When completed, I noticed there wasn't any upper mids coming out of the horn? I compared it to other ones and confirmed this.
I pulled out the brand new JBL 2432h driver, and removed the diaphragm. First thing I noticed was a oil substance in half of the gap. I cleaned that out and re-installed for a test. Still no mids. I removed the diaphragm again thinking I missed some of the oil. Using a cut plastic zip tie, I noticed the gap is not even. There is a tighter area where the zip tie gets stuck.
Is this driver held together with some sort of glue? Can I align the gap?
Is this a defect?

[Riley Casey]

Sounds like you cleaned out the brownish FerroFluid and if so now your power handling is reduced by 50%. Did the other similar drivers not have Ferrofuild? If you've confirmed that the gap isn't symmetrical then the pole piece has shifted. The fix if this is a ceramic or Alnico magnet is to demagnetize the driver, break the glue bond, recenter with new adhesive applied and remagentize. No idea if this is the procedure with Neo magnets.



I upgraded my PA with better JBL 1.5" drivers and had the stock ones left laying here. I got an empty JBL box and decided to fill it and make a monitor. When completed, I noticed there wasn't any upper mids coming out of the horn? I compared it to other ones and confirmed this.
I pulled out the brand new JBL 2432h driver, and removed the diaphragm. First thing I noticed was a oil substance in half of the gap. I cleaned that out and re-installed for a test. Still no mids. I removed the diaphragm again thinking I missed some of the oil. Using a cut plastic zip tie, I noticed the gap is not even. There is a tighter area where the zip tie gets stuck.
Is this driver held together with some sort of glue? Can I align the gap?
Is this a defect?

[engineerjoe]

Sounds like you cleaned out the brownish FerroFluid and if so now your power handling is reduced by 50%. Did the other similar drivers not have Ferrofuild? If you've confirmed that the gap isn't symmetrical then the pole piece has shifted. The fix if this is a ceramic or Alnico magnet is to demagnetize the driver, break the glue bond, recenter with new adhesive applied and remagentize. No idea if this is the procedure with Neo magnets.

Thank you.
The fluid seemed like it was all towards one side. I think it was the bottom half when it was mounted?
I usually don't take apart a new driver unless something is wrong. I can say, I've never personally blown a diaphragm. I do buy used stuff. That also has forced me inside of things when needed.
Back when I toured, if something broke, I had to fix it myself. I consider myself, a self appointed field tech. Now, I just dabble in sound with a low budget on a fixed income.

I installed a spare JBL 2453h driver and now the monitor sounds great. Seems a shame to have this lay around as a paper weight. If it is glued, that would lead me to believe it was that way from the factory. That might help explain why the upgrade of my main's horn drivers was needed.

[Riley Casey]

Ferro fluid should follow the magnetic field. If it was not evenly distributed around the gap that's suspicious. It's a fairly viscous, oily sort of liquid so if yours was watery perhaps it was something else.



Thank you.
The fluid seemed like it was all towards one side. I think it was the bottom half when it was mounted?
I usually don't take apart a new driver unless something is wrong. I can say, I've never personally blown a diaphragm. I do buy used stuff. That also has forced me inside of things when needed.
Back when I toured, if something broke, I had to fix it myself. I consider myself, a self appointed field tech. Now, I just dabble in sound with a low budget on a fixed income.

I installed a spare JBL 2453h driver and now the monitor sounds great. Seems a shame to have this lay around as a paper weight. If it is glued, that would lead me to believe it was that way from the factory. That might help explain why the upgrade of my main's horn drivers was needed.

[Robh3606]

Ferro fluid should follow the magnetic field. If it was not evenly distributed around the gap that's suspicious. It's a fairly viscous, oily sort of liquid so if yours was watery perhaps it was something else.

Depends on the amount used vs the gap size. I have seen ferro concentrated on one side as well in the 2341 and 2435 drivers when you take the diaphragm out. The viscosity varies with type.

Rob:)

[engineerjoe]

Kind of thick, like a thick oil or light grease. Just around a half of the circle.
I didn't notice if it was towards the thinner gap or not. I only guessed that it might have been at the bottom.
I never knew it made a difference in power handling. I've only seen it in one other driver. It was a (Myer sound?) JBL 2450 driver clone. That driver also had a weak click when checked. So I cleaned that one out and the sound was great after that.
I had thought I had helped it. It's mate is a regular JBL 2450 and there wasn't any oil inside that one.
I have to look into some sort of tech advice for using that stuff down the road!
Where do I get it?

[Don C]

Here's some.

https://www.amazon.com/Ferrofluid-900uL-General-Purpose-Diameter/dp/B00HX0L2XO/ref=sr_1_41?crid=3S1PSKLDHLDPX&keywords=ferrofluid&qid=1647564941&sprefix=ferrofluid%2Caps%2C269&sr=8-41

[Riley Casey]

It's been decades since I worked with choosing Ferro Fluid to add to drivers that didn't have it to begin with but I do remember there being at least two and maybe three versions with different characteristics so if you're trying to match drivers you'll want to learn from the vendor which to use for a given driver.