Sagging Voice Coils?

This isn't a theory, it's a fact. It's not like a cable type of discussion where people have different results, without any measurements to back it up. It's just like people put their classic cars on blocks to keep the springs from sagging. The spider and surrounds on the speaker are it's suspension. And gravity does pull them down, whether their forward, or downward firing. There is evidence of it around the world, not just theory. It's not something that comes out of the minds of bored audiophiles. I imagine if you ask any one that recones vintage speakers, they will probably have seen one that has damage from the voice coil, or former rubbing, do to sag. I have seen it visually, and felt it moving the cones.

If you check the net, there are a lot of people that heard what they describe as buzzing and was told to rotate their woofers, and they had good results after doing it.

Step six in this talks about sag in older drivers. I don't think it's their imagination, or something they dreamed up.
[http://www.decware.com/newsite/refoam.htm]

Supposedly, Lowthers are famous for this. The other thing is picking up dirt and all manner of other stuff in their voice coils, and needing to both rotate and clean out the gunk.

So far, with my Hornings, I've not done either. Then again, with their circumcised drivers, maybe it's not necessary? Or, perhaps, I'm just whistling through the graveyard...

circumcised drivers

ROTFL. Who knew? Horning doesn't sound Jewish ;-)