Foam in 2425 cover

[Eaulive]

I'm into the process of rebuilding 24 4604 stage monitors.
All of the foam pieces inside the cover of the 2425 drivers are done for, are those important for performance/reliability? Can they still be obtained? is it worth it to change them? Should I just forget it and go on with my life?

Thanks for any insight, the last option is very tempting

[Mr. Widget]

Clean out all of the old foam.

I don't know if the original is still available from JBL, but since you are out of the country, original parts are likely quite expensive anyway. I'd replace it with some similar self adhesive foam or thick felt that you can cut to shape. It isn't rocket science, but it does affect performance, so don't skip it.


Widget

[boputnam]

It isn't rocket science, but it does affect performance, so don't skip it.

+1

It's almost rocket science - it mitigates resonance and reflections inside the housing. As Widget sez, it is very important.

[Eaulive]

Clean out all of the old foam.

I don't know if the original is still available from JBL, but since you are out of the country, original parts are likely quite expensive anyway. I'd replace it with some similar self adhesive foam or thick felt that you can cut to shape. It isn't rocket science, but it does affect performance, so don't skip it.


Widget

I have easy, quick and cheap access to JBL parts, but haven't find a part number for this. Of course the cover is available but I'm not gonna change 24 covers just to get the foam

Also, I have no idea of the shape of the foam because they are completely pulverized. All is left is a pile of crud and a round sticker in the back of the cover

I'll drop a line to JBL this week, thanks!

[LikaComet]

Please let us know what JBL has to say.

Are there any images of this type of "gaurd"?

[Mr. Widget]

I have easy, quick and cheap access to JBL parts, but haven't find a part number for this. Of course the cover is available but I'm not gonna change 24 covers just to get the foam !

If you search this site you can find many answers.

http://www.audioheritage.org/vbullet...04&postcount=3

Also the dealer through which you order your parts should have the parts number available to him.

According to the current parts list, the price is now $2.94 ea.

http://www.jblproservice.com/pdf/Mis...by%20part).pdf


Widget

[robertbartsch]

I've had at least on piece of foam degrade so significantly, it resulted in a sticky residue substance being spread throughout the compression driver including the diaphragm and voice coil gap.

...so yeh, if the foam is starting to rot, remove and replace it.

[Eaulive]

Hey thanks!

61286, I have in my list, I was searching with the key word "foam" instead of "pad"

I could have search with 2425 to begin with, I know , DUH!

[Zonker92]

Reviving this ancient thread, I have a pair of 4430s sold new in 1987 with 2425 drivers. The speakers are in mint condition and have always been used and stored in relatively dry, not humid, areas. Are the damping pads almost certainly due for replacement?

Also, I tried removing one of the 2425 end caps, but after taking out the screws, it wouldn't budge. Should I just gently pry it off or something? Is the diaphragm pretty safe from damage so long as I'm careful not to touch it? I would just hate to damage it by removing the end cap.

Thanks.

[grumpy]

I have a pair of 4430s sold new in 1987 with 2425 drivers. The speakers are in mint condition and have always been used and stored in relatively dry, not humid, areas. Are the damping pads almost certainly due for replacement?

yes.

Also, I tried removing one of the 2425 end caps, but after taking out the screws, it wouldn't budge. Should I just gently pry it off or something? Is the diaphragm pretty safe from damage so long as I'm careful not to touch it? I would just hate to damage it by removing the end cap.

I just tap sideways, holding the cap and driver together with the other hand (you don't want it to come loose and fly around, there is a rim
around the diaphragm, but it's still exposed):

[Zonker92]

Cool; thanks, Grumpy! Much appreciated.

[more10]

A friend of mine uses asphalt glue and Twaron instead.

[NickH]

I've alway wonder if some rock wool would work in there? I have 1 2445 that needs the foam replaced. Plus the foam was bad in my 2440's so I took it out. The odd thing is there was felt underneath it. I recall that they originally used felt. But I never read that some had both.

Sorry for the semi off topic.

Nick