N Cook wrote:


If you took a cone from a 12 inch and a 15 inch and laid them face down on a
surface. Then a flat plate on the cylinder extension of the 12 inch and then
some weights on that, but not enough to cause it to collapse.
Then add the same plate and weights to the 15 inch and before the cone would
collapse by compression or radial buckling, would not the larger one be more
likely to start to fail by the central section twisting and then collapse.
Less torsional stiffness is probably the term I'm looking for.

I don't really understand where you're coming from, the only 'weight' on
a speaker cone is the voice coil assembly and dust cover and they weigh
very little, even in a high power speaker. compared to PA speakers,
guitar amp speakers are often deliberately made with reduced cone
stiffness so that they 'trash out' at lower volumes.

In the back of my mind, I do recall seeing a photo of a speaker cone,
face down, with a chap standing on the voice coil former to demonstrate
the strength of the cone assy. I don't remember which company it was.

Most pro speakers have very rigid cone structures, it`s pretty uncommon
to find a professional speaker failure that is attributable to
mechanical damage during use, even over excursion is fairly rare - tho
dj`s do try their hardest.

Almost all pro speaker burnouts are due to being driven with amplifiers
of insufficient headroom,[1] or some external failure i.e. Bad switch
on sequence etc.

There was once a company called Baker who made probably the worse
speakers in the world, the skinny cast alloy baskets would crack,
dumping the puny magnet in the bottom of the cabinet - happily long in
the past.

[1] That statement may lead to flameage

Ron(UK)