Having worked in manufacturing for many, many years and being a Certified Quality Engineer, I know a single sample (i.e. your situation) does not make a trend, but instead, identifies the potential for a quality issue.
Similarly, what you have could simply be the result of what we called an "outlier". a statistical anomaly that could have resulted from imperfect workmanship and/or incomplete adherance of the slit sealer to the seam.
Similarly, what you have could simply be the result of what we called an "outlier". a statistical anomaly that could have resulted from imperfect workmanship and/or incomplete adherance of the slit sealer to the seam.
This is exactly a reason why I would not allow good looking
secretaries pass through assembly lines.
The fact that the second one, which looks perfect, is distorting similarly to the one with the visual separation, is significant. The failure is time based and progressive. I assume they are aware of the problem and have addressed it. These are after all, close to a decade old.
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I agree cars are much worse environment. The only thing slightly out of the ordinary in these drivers' environmental history is the elevation ((9,100 ft), and therefore low humidity. The fact that people aren't hearing anything wrong doesn't prove that their drivers haven't begun to deteriorate and distort. It just means they can't hear it, like the owner of these speakers (supposedly). It was easy for me to hear the distortion in the speaker shown in the first post, but the second speaker sounded pretty good with music, but on sine waves near 440 is went wild with distortion. Piano is good for revealing this type of distortion if test tones aren't handy. Then again, maybe they (Scan Speak) went to a longer lasting glue soon after these were made many years ago, or maybe this pair was just from a bad batch as others have suggested. It's easy enough to test if you own a pair, you don't even have to remove the drivers from their cabinets. Just send some tones near the lower end of the driver's operating range, or if you don't know, 440 (orchestra A) should work fine.
As for the glue being water based with added black colorant, that's exactly what it looks like. Maybe they didn't use enough, or maybe the low humidity just sucks so much moisture out of the glue after several years time that it loses the flexibility required to do its damping job at first, which causes harmonic distortion to go way up, and then its adhesive job altogether, which causes the completely out of control kazoo distortion, which I think even people in a moving car would hear.
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Your signature line is interesting, but begs the question: "How do we know when we know just enough"?
It would be very interesting to learn precisely what they apply. I use the 15W in my 3-way and am surprised to hear of your problem. Mine aren't to far from the age of yours, but I'm in a more typical environment, more moisture in the air. Still, I'll keep my eye on them.
The link to this thread was provided over at the PE forum in a thread on some testing of a driver mod like the slits in the SS. I mod drivers a bit and have used a product that seems very similar to those used on many commercial drivers. It's available at Parts Express and is called "The Wet Look". It's a water based high gloss polymer (black or clear). Applied to the cone/surround junction of non-metal drivers it does a very good job of reducing resonances due to the impedance mismatch. When dry it has the look and feel of the commercial driver applications.
The price has gone up since I bought a small bottle, but it's still only $7.50 plus shipping. The link is here.
I don't know how you might apply it and have it be not noticeable. I use a very small brush, but can't match the manufacturer's application quality. For touchup, that might be enough.
Dave
Dave, do you know if this application in the cone is glue or another material? The color (and syringe) is similar to the previous glue application.
Seas MS5 13F-GMBX H095 Lautsprecher reparieren Sicke refoam haut parleur reparation - YouTube
Seas MS5 13F-GMBX H095 Lautsprecher reparieren Sicke refoam haut parleur reparation - YouTube
I don't know. I've re-foamed a driver only once. The glue came with the re-foam kit. My thought at the time was that the glue (white, in a tube applicator) was simply carpenter's glue. I used it only to attach the surround. What the guy in that video is applying, that he also applied to the cone, is likely something else. I wouldn't think that something that dries hard would be good to apply to a cone, but he used it for the surround glue as well.
He does a really good job.
dlr
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