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Repairing a Celestion 15 inch speaker?

N

N Cook

Jan 1, 1970
0
Someone threw something at this speaker in a Carlsbro Cobra combo.
It works with distortion.
By digital probing (using my fingers) at about 4 o'clock position ,
unpowered, the rubbing resistance feel to movement of the cone disappears.
Same if powered up, no distortion, to a power level where the effect of my
fingers damping comes into play.
Is there a liquid that will contract on drying to paint radial stripe on
cone and dry and test, repeated until problem goes plus one or two more
stripes.?
Or would freeing the rim or part of the rim of the cone by hot-air heationg
and reseating all or part be better.
If part then release 2 to 6 o'clock say and pull or 8 to 12 o'clock and
push, my guess is pull would be better.
Any other ideas? rather than throwing out at this stage, if it doesn't work
then just lost a bit of time and learnt a bit maybe.
 
N said:
Is there a liquid that will contract on drying to paint radial stripe on
cone and dry and test, repeated until problem goes plus one or two more
stripes.?

I have heard of minor cone tears being treated with ladies nail
varnish. Professional reconing is an option. Celestion still exist as a
company and may be able to advise
 
A

Arfa Daily

Jan 1, 1970
0
I have heard of minor cone tears being treated with ladies nail
varnish. Professional reconing is an option. Celestion still exist as a
company and may be able to advise

If it's a pressed steel frame, you can sometimes recover such
location-specific voice coil drags, by deliberately distorting the frame in
the opposite way, so that the cone is recentralised. Crude, but often
effective.

Arfa
 
N said:
Someone threw something at this speaker in a Carlsbro Cobra combo.
It works with distortion.
By digital probing (using my fingers) at about 4 o'clock position ,
unpowered, the rubbing resistance feel to movement of the cone disappears.
Same if powered up, no distortion, to a power level where the effect of my
fingers damping comes into play.
Is there a liquid that will contract on drying to paint radial stripe on
cone and dry and test, repeated until problem goes plus one or two more
stripes.?
Or would freeing the rim or part of the rim of the cone by hot-air heationg
and reseating all or part be better.
If part then release 2 to 6 o'clock say and pull or 8 to 12 o'clock and
push, my guess is pull would be better.
Any other ideas? rather than throwing out at this stage, if it doesn't work
then just lost a bit of time and learnt a bit maybe.

the solution is to move the cone assembly sideways a tiny bit, not at
the rim but near the centre. If you can unfix thespider and then centre
it, problem solved. If not, other than reconing, putting sideways force
onto the cone assembly can bodge it and make it work ok. This is done
by makeing a hook shape and sinking the short sharp end of it into the
spider, and pulling and fixing to the frame. Its a bodge, but you might
want to do it to try to avoid a recone.

Dont repair cone damage with rigid materials like nail varnish, the
varnish etc will break after a bit and then the whole thing sounds
terrible. Always use a flexible glue. It does need to be a strong glue.


NT
 
N

N Cook

Jan 1, 1970
0
Arfa Daily said:
If it's a pressed steel frame, you can sometimes recover such
location-specific voice coil drags, by deliberately distorting the frame in
the opposite way, so that the cone is recentralised. Crude, but often
effective.

Arfa

Didn't expect it to be so easy.
The central dome was buckled in. Drilling a few 1mm holes
and using a dental sickle brobe managed to pull it back into reasonable
shape.
Somehow that corrected things, just a small puncture in the cone periphery
to patch over now.
 
N said:
Didn't expect it to be so easy.
The central dome was buckled in. Drilling a few 1mm holes
and using a dental sickle brobe managed to pull it back into reasonable
shape.
Somehow that corrected things, just a small puncture in the cone periphery
to patch over now.

I trust youve sealed up the little holes, that needs doing else muck
gets in the very tight spaces between cone and pole magnet and the
speaker's then stuffed.


NT
 
D

Dave Curtis

Jan 1, 1970
0
Didn't expect it to be so easy.
The central dome was buckled in. Drilling a few 1mm holes
and using a dental sickle brobe managed to pull it back into reasonable
shape.
Somehow that corrected things, just a small puncture in the cone periphery
to patch over now.


Try to find some Plio-bond. Apply it to the edges of the tear with a
toothpick and carefully fit the tear back together. If you have a
small piece missing, make up a patch to fit using construction paper
and glue it in place. You said puncture, so I'm thinking all the paper
is still there.

Don't use Elmer's glue or nail polish; they're not very flexible when
they dry.
-Dave
 
Stiff glue is fine if the part of the speaker where it is used is
stiff, it is only around the flexible periphery that the stiff glue
should not be used.

H. R. Hofmann
 
D

Dave Curtis

Jan 1, 1970
0
Stiff glue is fine if the part of the speaker where it is used is
stiff, it is only around the flexible periphery that the stiff glue
should not be used.

H. R. Hofmann

Actually, many parts of the cone that seem stiff will flex quite a bit
when the speaker is driven hard, not just the surround.

-Dave
 
O

OLDFART

Jan 1, 1970
0
At EAW before they got, um, 'LOUD', we used to treat 5" mid
speakers with a 95%/5% mix of Elmer's and water. The water
would break up the Elmer's enough to flex. Later, we found
another 'wood based' glue (forget the name) and did the same
mix ratio, with alot better results. I used an old 78 turntable
I'd place the speaker on, and set it at 16...and paint..faintly.

The folks at RCF speakers came over, saw the setup and told
me they did the SAME turntable trick in Italy. AWESOME folks..

This 5" speaker would then drive the wood formed mid 'horn'
of the cab, and increased mid range response big time.

KF at EAW is on the level of Leo N Jim, HP and D Reeves,
or any other ICON in this business. Great guy, taught me alot.

Taught me how to re-cone speakers in mass qualities..the right way..


JJTj



www.oldfartdays.com









I am frolicsome, I am easy,
Good tempered and free,
And I don't give a single pin' me boys
What the world thinks of me.
 
OLDFART said:
At EAW before they got, um, 'LOUD', we used to treat 5" mid
speakers with a 95%/5% mix of Elmer's and water. The water
would break up the Elmer's enough to flex. Later, we found
another 'wood based' glue (forget the name) and did the same
mix ratio, with alot better results. I used an old 78 turntable
I'd place the speaker on, and set it at 16...and paint..faintly.

The folks at RCF speakers came over, saw the setup and told
me they did the SAME turntable trick in Italy. AWESOME folks..

This 5" speaker would then drive the wood formed mid 'horn'
of the cab, and increased mid range response big time.

KF at EAW is on the level of Leo N Jim, HP and D Reeves,
or any other ICON in this business. Great guy, taught me alot.

Taught me how to re-cone speakers in mass qualities..the right way..


JJTj

Why not just brush paint it in situ? Thats what I did, cba these days
though.

Re somene elses comments earlier, all parts of the cone assembly flex
in use, just some more than others.


NT
 
OLDFART said:
At EAW before they got, um, 'LOUD', we used to treat 5" mid
speakers with a 95%/5% mix of Elmer's and water. The water
would break up the Elmer's enough to flex. Later, we found
another 'wood based' glue (forget the name) and did the same
mix ratio, with alot better results. I used an old 78 turntable
I'd place the speaker on, and set it at 16...and paint..faintly.

The folks at RCF speakers came over, saw the setup and told
me they did the SAME turntable trick in Italy. AWESOME folks..

This 5" speaker would then drive the wood formed mid 'horn'
of the cab, and increased mid range response big time.

KF at EAW is on the level of Leo N Jim, HP and D Reeves,
or any other ICON in this business. Great guy, taught me alot.

Taught me how to re-cone speakers in mass qualities..the right way..


JJTj

Why not just brush paint it in situ? Thats what I did, cba these days
though.

Re somene elses comments earlier, all parts of the cone assembly flex
in use, just some more than others.


NT
 
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