LE14-1 noise

[sweet212]

Hi

can anyone help me?

My newly acquired 250ti Classics has a woofer that "rattles".

I pulled out the LE14-1 woofer measured the dc resistance 6 ohms - thats good. Then connected a signal generator and the rattle was obvious. The surround has separated from the cone on one side. I assume the voice call is making contact. That IMO is definitely not good.

So my question is. Do I replace the surround and hope that it centers in the voice coil again or do I replace the whole cone?

I live in WNC - does anyone here know and recommend a speaker service center that can do this work?

Thanking you in advance.

[Don C]

The remaining surround could itself be making noise by flapping as the cone moves. I'd re-foam and test again.You should be able to feel if you are getting voice coil contact as you are installing the new foam, and hopefully adjust the centering so that there is none.

[sweet212]

The remaining surround could itself be making noise by flapping as the cone moves. I'd re-foam and test again.You should be able to feel if you are getting voice coil contact as you are installing the new foam, and hopefully adjust the centering so that there is none.

Thank you Don

I will try that.

BTW: Wasn't Santa Rosa burned by the recent fires?

Regards

[sweet212]

The remaining surround could itself be making noise by flapping as the cone moves. I'd re-foam and test again.You should be able to feel if you are getting voice coil contact as you are installing the new foam, and hopefully adjust the centering so that there is none.

I had a JBL authorized dealer re-foam the woofers and picked them up yesterday. Connected a signal generator before reinstalling them to test them. At low frequencies below 30 hz where the cone is moving a 1/4" or so there is slight, light scraping noise. Like paper touching somewhere in the voice coil. At higher frequencies the scraping turns into a slight buzz. Pushing the cone equally around the dust cap reveals no contact or sound. It may be just distortion in the signal generator.

Should I be concerned or just ignore it?

[Earl K]

I had a JBL authorized dealer re-foam the woofers and picked them up yesterday. Connected a signal generator before reinstalling them to test them. At low frequencies below 30 hz where the cone is moving a 1/4" or so there is slight, light scraping noise. Like paper touching somewhere in the voice coil. At higher frequencies the scraping turns into a slight buzz. Pushing the cone equally around the dust cap reveals no contact or sound. It may be just distortion in the signal generator.

Should I be concerned or just ignore it?

Sounds like you may have a case of ( crumbling ) internal foam-filter rot where the disintegrating foam migrates into the voice-coil gap.
- these pieces of foam are a ticking time bomb for all JBL woofers of this vintage ( ie; the ones having ferrite magnets sporting a single vent in that magnet ).

If your re-foamer had removed the dust-cap for refoaming he would have been able to clean the gap during the re-foam procedure.

I'll have to assume that this wasn't done ( dust-cap removal ) and he simply centered the voice-coil using a LF tone.

I'd take both woofers back to him, have him remove the dust-caps and clean the gaps of all foam ( then replace the foam filters with one made from plastic mosquito netting > as an example ) and then put some JBL-correct dust-caps back in place.

Just my 2 cents.



BTW; Here's what an intact foam filter looks like on a broken magnetic structure ( ie; the glue failed on the magnet of this old JBL 15" > was not mine ! ).

[Earl K]

Here's a blog that I feel is most likely quite relevant to the health of your le14h's.

Appropriately called; Dang it, JBL!

[sweet212]

Here's a blog that I feel is most likely quite relevant to the health of your le14h's.

Appropriately called; Dang it, JBL!

Thank you Earl

I will read your attachment tomorrow and thanks again.

Cleaning out the old filter material by removing the dust cap would need replacing the whole cone - I assume. These old LE14 cones are hard to obtain.

Or could the old cap be cut and then glued back in place? Is that possible?

[Earl K]

Thank you Earl

I will read your attachment tomorrow and thanks again.

Cleaning out the old filter material by removing the dust cap would need replacing the whole cone - I assume. These old LE14 cones are hard to obtain.

Or could the old cap be cut and then glued back in place? Is that possible?

Dust-caps can be cut-out by techs skilled with using x-acto knifes.

[sweet212]

Dust-caps can be cut-out by techs skilled with using x-acto knifes.

Thanks Earl

It seems removing the dust cap and vacuuming out the remains of the filter may work.

Perhaps the best way would be to remove the cone and thoroughly clean and remove all the old filter.

However can the old cone be replaced? Replacement LE14 cones are as rare as hen's teeth.

What to do?

[sweet212]

Thanks Earl

It seems removing the dust cap and vacuuming out the remains of the filter may work.

Perhaps the best way would be to remove the cone and thoroughly clean and remove all the old filter.

However can the old cone be replaced? Replacement LE14 cones are as rare as hen's teeth.

What to do?

I connected the woofers directly to the amp and found the basiest music I could find. Surprise! They sound fine - I could not hear any rubbing or other sounds.

When acoustically loaded back in their enclosures may be a different story. I will try that - so thanks for all your help - most appreciated.

[Earl K]

Hi,

Some reading for you re; using a vacuum to clear out the foam.

[RMC]

Hi Earl,

I share your concern about using a regular household vacuum cleaner and/or even a Shop Vac to suck the old foam. In fact in my view this is more dangerous than helpful, unless the foam would be like dust, which I haven't seen yet...

The succion is just too strong in these machines and the risk of further damage too high. I don't really see how rotten STICKY foam could be ALL sucked out through the driver's back vent screen. No way from what I've seen up to now.

When refoaming my 2214H drivers I did cut open the dustcaps (except near the wires to re-glue them after), and used copier paper strips to clean the VC gap carefully in a cicular motion to loosen/remove dirt, dust and foam from one hand, while using in the other hand a less powerful small 12 volt battery hand held vacuum cleaner to suck the debris loosened/removed out of the gap by the paper strips. I even made myself sort of a small plastic "fitting" at the end of the vacuum so I coud direct the succion precisely and get as close as possible to the gap to get everything out.

Bingo! That method worked well, if one is patient and careful, with no danger of scrapping anything. All the garbage is out. The woofers are as happy as I am...
To cover the back vent again for dust or glass wool fibers protection, I used slightly stretched speaker grill cloth glued over the vent. Regards,

Richard