Blues Deville speaker problems

[Rhodesplyr]

I was wondering if anyone else has had problems with the stock Eminence speakers in a Blues Deville amp.

A client brought one in complaining of weird harmonics, and I isolated it to one of the upper speakers. It turned out that the seam in the cone had come unglued at the surround, so I reglued it with latex glue used for speaker repairs. We tested it today, after the glue was thoroughly dry, and there was still some buzzing on certain notes coming from that speaker. I'm thinking that perhaps I need to paint a layer of glue down the whole seam. I know what voice coil rub generally sounds and feels like, and I don't think that that's the problem.

Anticipating the "How do you know it's that speaker?" question, I sent a buzz-producing signal through the amp, and, with ear protectors on, I damped the speaker cones slightly with my fingertips one by one. When I got to the problematic one, the buzzing stopped.

This is making me think: what is the special appeal of speaker cones that have a glued seam running up the cone?

[jmaf]

I wasn't the guy who fixed speakers when I worked in repair, but I always watched the speaker work and I know from that experience that you probably need a new cone for a more definitive solution. The gluing won't do in the long run, it'll come apart sooner rather than later and the speaker probably won't sound good with glue on one side of the cone, no matter how nice a job you make it.

Torn cones = new speakers or a revamp of the existing one. Glue should be emergency measure only IMO.

[Rhodesplyr]

I've actually had pretty good luck with cone repairs; I use an artist's brush and only use as much glue as I need.

In this case, however, I've determined that the crack probably wasn't the source of the ghost tones to begin with because fixing the cone didn't really affect the problem at all. I had one 1950s Jensen speaker that did the same thing, and it turned out to be a partial failure of the glue joint between the voice coil former and the cone.

In any event, that type of surgery is beyond what I'm set up to do, so it's recone or replace.

[jrfrond]

That's an OLD amp then, because Fender sent out a service bulletin addressing the problem with those 10" Eminence drivers 15 years ago ('96). Not all of them fell apart, and some took longer than others when they did.

The proper way to repair those is to cut the dust cap off carefully with a sharp X-Acto knife, shim the voice coil in the gap, and apply medium or thick CA adhesive to the area where the cone meets the coil form. Once it's cured (or you can hit it with accelerator), you remove the shims and install a new dust cap of the same size. Since I do reconing, I keep many sizes (and adhesives) in stock, so it's not an issue.