Help with weird buzz

[nickb]

Put a signal into it and listen or gently and evenly push on the cone a few times to see if you can feel or hear a rub.

[Cretins]

The buzz that I was originally dealing with is gone, vanished, but when i do like you say and push on the cone gently I do get a buzz but still not as bad as it was.

[nickb]

The buzz that I was originally dealing with is gone, vanished, but when i do like you say and push on the cone gently I do get a buzz but still not as bad as it was.

Are you doing the test with no signal into the speaker or playing of guitar?

[Cretins]

Guitar...I put it all back together in the cabinet and it sounds great. The only thing different is I removed the old gasket on the outer rim (the 1/8" what looks like pressed board gasket), it basically fell off as I was removing speaker from the cab so I guess that gasket was making the rattle.

[nickb]

Guitar...I put it all back together in the cabinet and it sounds great. The only thing different is I removed the old gasket on the outer rim (the 1/8" what looks like pressed board gasket), it basically fell off as I was removing speaker from the cab so I guess that gasket was making the rattle.

Bazinga!

[Cretins]

Ya, now I feel like an idiot

[eschertron]

Ya, now I feel like an idiot

It's called "troubleshooting". Ya did all right

[Cretins]

Thanks, and to think I was one click away from buying a re-cone kit for a Blue that someone on ebay is selling for $42.

[g1]

Sometimes even uneven torque on the speaker mounting screws can distort the cone enough to create buzzing. Loosening off the screws a bit at a time is something to try when troubleshooting similar issues as you had with this one.
Another option is a loose screw (rather than too tight) could have been a factor. Did you notice any loose when removing?

[Enzo]

it is also possible something was sitting in between the backside of the cone and the basket frame. I find guitar picks sitting inside speaker backs all the time, and they many time cause buzzes. Something like that may have fallen out when you removed the speaker.

[eschertron]

During my service in the US Navy, it seemed as though every maintenance procedure would start out with
Step 1: clean and inspect
There's a lot that can be found and solved without going any further. Something akin to the 'laying on of hands' mentioned by RJB in this thread.
http://music-electronics-forum.com/t29623/

[Cretins]

You got that right eschertron, I can't even tell you the number of times I've taken something that wasn't working apart, cleaned things up, and put back together and viola, it ends up working fine again.
I do believe the problem this time was that the gasket was just old and brittle.

[J M Fahey]

Something to consider and keep in the "possible" basket, just in case.
Iīm intrigued by the " gasket was just old and brittle" bit, because the speaker in no way is old enough for that.

Itīs something I have seen on 50/60 years old Jensen (and similar) speakers but there itīs justified on 2 counts:

1) they are 50/60 years old ... this Celestion is 15

2) waaaay back then the only adhesive available was the infamous "speaker cement", imagine you buy a can of transparent old style Nitro lacquer , what was used to paint cars , guitars and bicycles, and leave the can open for a week or a couple days in the sun so half the solvent evaporates and it becomes honey thick.

This adhesive is poor on many surfaces ,specially on non porous ones such as metal or glass, and chemicall unstable (itīs *really* smokeless powder dissolved in acetone) so it becomes brittle with age.

As mentioned before, I have seen and repaired scores of old speakers which were not burnt by any means, but had loose or directly separated cones from frame, suspensions, or at least loose or fallen dustcaps.

But ... on a 15 y.o. Celestion?

Admittedly, it tries to be a faithful repro on every bit, so voice coil has wire bonded with nitro adhesive on plain paper, and voice coil glued to cone and spider , good or bad itīs *needed* there to give it a unique sound , since such adhesive is quite fluid (instead of jam density of Epoxy) and 10/15% solids , 85/90% solvent evaporates (epoxy 100% stays there) , dried adhesive can be 20X lighter than a modern epoxy glued one (what, say, Eminence uses).

But there is no need at all to use it on cone and suspension edges , and gaskets, because those parts do not move, so there is no advantage on its lightness.

Unless somebody decided based on "Mojo" and cloned *everything* on an original early 60īs Blue , good or bad.

From the kind damage you describe, I guess that was the case.

Or worse: old adhesives if too liquid were absorbed by cardboard , very little remained on the contact surface, and poor joints were achieved ... I suspect something like that, the speaker might have been assembled by a worker used to *modern* Celestions.

[Cretins]

You're right Juan, I should not have referred to the gasket as old and brittle, just maybe the glue that held it in place. Here's a section of the gasket front and back, the glue is very thin.

[Cretins]

Just that gasket.