Speaker rattle caused by small debris hidden somewhere

[J M Fahey]

THIS attached here is the rattling noise inside my speaker. It sounds rather loud because it has been recorded from a very close distance, but that's it:
[ATTACH]38995[/ATTACH]

I can't believe it, it's incredibly loud and clear.
It sounds like a couple nails inside a plastic glass or dice inside a throwing cup or wooden matches in a half empty box.

I can't believe you can see nothing there, it sounds 10 times larger than I expected.

And it's jumping around, not at the end of any pod.

As of the strong solvents mentioned, yes, they are needed to redissolve the spider to frame and cone to frame glue.

After a few minutes they become honey liquid again, and cone and spider can be pulled away without damage.

You'll have to desolder flexible leads from terminals, of course.

[olddawg]

That would not remove any debris in the gap, which is typically where the problems occur. I would remove or fold over the cap (tape it to the cone if you do) and use a strong vacuum cleaner nozzle on it.

[slidincharlie (Carlo P)]

I can't believe it, it's incredibly loud and clear.
It sounds like a couple nails inside a plastic glass or dice inside a throwing cup or wooden matches in a half empty box.

Yes, it is almost like you said - even considering the close recording distance the rattle is clear.

I can't believe you can see nothing there, it sounds 10 times larger than I expected.
And it's jumping around, not at the end of any pod.

I said that it could be attached at a pod because I can hear the rattle ONLY in one specific spatial positioning of the speaker - if I flip it to a different position the rattle disappears.

[slidincharlie (Carlo P)]

I've used a small wooden stick and my pinky to search inside, no vacuum cleaner though.

That would not remove any debris in the gap, which is typically where the problems occur. I would remove or fold over the cap (tape it to the cone if you do) and use a strong vacuum cleaner nozzle on it.

Do you mean that removing the cap and using a vacuum cleaner I should be able to remove debris somewhere else other than the voice coil cylinder that I have already explored (green area in the drawing below)?
I am scared about those two tiny filaments...

[slidincharlie (Carlo P)]

That would not remove any debris in the gap, which is typically where the problems occur. I would remove or fold over the cap (tape it to the cone if you do) and use a strong vacuum cleaner nozzle on it.

I lifted the dust cap fully open and used the vacuum cleaner but the sucker is still there...
BTW, I can't see any gap between the walls and bottom of the cylindric space below the cap. In case the debris is in the air gap beneath the spider, how would I take it out from there?

[Jazz P Bass]

O/k.

Run a piece of paper around the air gap to see if anything is hanging up.

Now play it without the cap.

My feeling is the speaker simply needs a recone.

[slidincharlie (Carlo P)]

O/k.
Run a piece of paper around the air gap to see if anything is hanging up.
Now play it without the cap.
My feeling is the speaker simply needs a recone.

I've run a piece of paper inside the tiny gap at the bottom of the cylindric space under the dust cap, all around the perimeter. The rattle is still there when I shake the speaker.
THEN I played the speaker with the dust cap removed and the rattle is gone
I need to play it louder to hear if it really sounds fine, and I will try also varying the angle of installation (that is, rotating the spaker in different positions inside the cabinet).ù
Any cue about what happened with the dust cap open?

[J M Fahey]

Yes, 2 possibilities:

a) your dust cap was loose , probably cracked brittle adhesive, you pulled dust cap, you removed the problem.
A new, freshly glued dust cap will not show problems for the next 30 years, as the old one did.

b) there *was* some debris loose jumping around in the free space inside the voice coil cylinder, roof the dust cap, floor the center pole, and your paper sheet or simply fumbling around there removed it.

I was chiming in to say that it's impossible that you didn't see *something* loose which by the noise was at least as large as a matchhead, but if it's gone, it's gone

[slidincharlie (Carlo P)]

UPDATE

Yes, 2 possibilities:
a) your dust cap was loose , probably cracked brittle adhesive, you pulled dust cap, you removed the problem.
A new, freshly glued dust cap will not show problems for the next 30 years, as the old one did.
b) there *was* some debris loose jumping around in the free space inside the voice coil cylinder, roof the dust cap, floor the center pole, and your paper sheet or simply fumbling around there removed it.
I was chiming in to say that it's impossible that you didn't see *something* loose which by the noise was at least as large as a matchhead, but if it's gone, it's gone

An update that will not bring much clarity I am afraid:
1) the debris (or whatever it is) IS still therein. I can clearly hear it when I shake the speaker in a precise position (no rattle in other different positions - this is what makes me think that it is something hanging down from a thin thread);
2) the rattle can be clearly heard OR NOT according to the installation position inside the cabinet. In the current speaker position there is NO rattle (hooray!); if I put it back to the previous position (that is, with the soldering lugs pointing upwards to the capinet top) there IS a rattle.
3) I don't have a new dust cap so I'll reglue the old one in place, hoping that the 'position' trick works.
I would be much happier if I was able to take the 'debris' out but I have no clues about how to extract it without totally dismantling the speaker.
Any further comment is welcome.

[J M Fahey]

Of course, an Enzoism : "when it starts working, stop "fixing" it"

Meaning: since you found a way for the noise to stop, leave it as is.

[slidincharlie (Carlo P)]

Of course, an Enzoism : "when it starts working, stop "fixing" it"
Meaning: since you found a way for the noise to stop, leave it as is.

That's exactly what I'm gonna do except for gluing the old dust cap back, just to prevent dust (or other evil debris...) to get in there.