Sagging Voice Coils?

Rodman, if your referring to me, the woofer cone is pulling on the spider causing the distortion in its (spider) shape. If there was no cone weight on it, I doubt the spider would sag in its lifetime. The midrange and tweeter with their light cones gives anyone an idea, the spider itself is not the problem. That's self explanatory with the woofers weight being the major cause of this problem. FWIW, there's still a problem with sagging from the weight of the cone. Some have it more than others. Larger gaps allow for more error. Also lighter cones, stiffer surrounds, and stiffer spiders along with other design factors come into play for the failure rate. Again, the problem still exists for some.

Michael, I'm embarrassed to admit I wasn't present at the bris.

I'm just talking from my personal experience, as a speaker reconer. The article YOU cited, was referring to the spider sagging towards the magnet structure(not the frame), and states exactly that. Like I said, I don't doubt that could occur, do to age, but- my encounters have been a result of damage caused by Florida's high humidity.

The article should be more specific. They should state something in the order that the sag could cause it to be off center. I think their main concern is to get the person doing it with no knowledge, good even clearance around the coil. If they're referring to upward firing woofers, I can't think of any companies that do this. I wasn't sure if you knew that I understand how the speakers are designed. I think we both know what is going on.

After looking at it and reading it again, they may also be concerned that the person doesn't push the former all the way down, and bottom it out especially more so, since they use shims.