PDA

View Full Version : "044" & "Others"?



Wagner
04-26-2010, 06:25 AM
If I have already asked this and forgotten, please forgive :)

Is there an acceptable/determined to be so, solution for renewing the foam damping behind the diaphragm domes (short of buying a new diaphragm assembly)?

I have no ability to experiment and sweep check so I was hoping someone could make a specific recommendation for a material I could simply procure, cut and install. Size or weight would be extremely helpful too.

"044"s are my main interest, but I have some aging "035Ti"s as well.

I'd like to have the the ability/option to refresh, if needed, when I have them out of their holes while doing other work

Thanks to all :bouncy:

Thomas

Wagner
04-26-2010, 06:46 AM
The question is not a new one:

http://www.audioheritage.org/vbulletin/showthread.php?27605-044ti-Advice-Sought&highlight=044+foam

Hi grumpy and thanks.

Yeah, I've seen it discussed before, I was mainly interested in if someone had identified a good, specific replacement, like "Acme Super DeLuxe Window Foam" available at a dime store near you. In other words, is there a known quantity?

Not being a smart ass, but I can't touch the sample in the photos to get an idea as to how to guess what to try. I would feel better as well knowing that another member had verified good results.

Thanks again,
Thomas

grumpy
04-26-2010, 07:24 AM
I understand, but short of an actual kit, it's guesswork.

fine, soft, open-cell foam is what I've taken out, and put in
(actual kits).

something like this, perhaps:

http://www.mcmaster.com/#polyurethane-foam-cubes/=6tufrz

(http://www.mcmaster.com/#polyurethane-foam/=6tu809)

Wagner
04-26-2010, 07:58 AM
I understand, but short of an actual kit, it's guesswork.

fine, soft, open-cell foam is what I've taken out, and put in
(actual kits).

something like this, perhaps:

http://www.mcmaster.com/#polyurethane-foam-cubes/=6tufrz

(http://www.mcmaster.com/#polyurethane-foam/=6tu809)


Thanks again.

Looks good on paper. What did you get, the 1" cubes?

I've emailed them to see if they have a minimum order policy.

Thomas

grumpy
04-26-2010, 08:43 AM
No, I used actual JBL kits... didn't mean to imply I had used that particular
material. Having had the real-deal to squish between my fingers just gives me
an idea of what might be a suitable replacement. The 044's I've repaired were
all fixed for a reason (open voice coils), so I don't have a subjective, or measured
before/after to judge what difference an old/squished/deteriorated foam piece
vs. a new one (that did noticeably require a small amount of compression under
the dome) makes... or a how foam with -slightly- different density or compressibility
might change things (just guessing not a lot).

McMaster-Carr is just a vendor that carries an insane amount of hardware
and was what came to mind... a search brought up the material I referenced...
-appeared- by description to be reasonably close.

Wagner
04-26-2010, 08:52 AM
No, I used actual JBL kits... didn't mean to imply I had used that particular
material. Having had the real-deal to squish between my fingers just gives me
an idea of what might be a suitable replacement. The 044's I've repaired were
all fixed for a reason (open voice coils), so I don't have a subjective, or measured
before/after to judge what difference an old/squished/deteriorated foam piece
vs. a new one (that did noticeably require a small amount of compression under
the dome) makes... or a how foam with -slightly- different density or compressibility
might change things (just guessing not a lot).

McMaster-Carr is just a vendor that carries an insane amount of hardware
and was what came to mind... a search brought up the material I referenced...
-appeared- by description to be reasonably close.


Understood.
They have no minimum so that's good.

So, as it stands now, maybe the softest, open cell "Super Deluxe" I can find locally might just work as well.

Large enough piece (height) to just lightly "kiss" the back of the dome?
Same diameter as the pole piece?

Thank you again,
Thomas

grumpy
04-26-2010, 09:31 AM
foam just cleared vc former on the inside dia.

height of foam in stock kit was surprising...
sufficient to touch the dome interior at its highest point
away from the pole piece, requiring some compression.

Note that -all- of the old foam pieces I've extracted had
(over time) permanently conformed to the dome shape,
having started with a flat top.