Ron(UK) wrote in message
...
N Cook wrote:

I've not literally been able to get my hands on this one yet - still
with
the owner , he decided to aquirt the universal solve-all in there -
WD40.


Well if it wasn't knackered before, it is now! Save the WD40 for rusty
gate hinges, it has no place at all in an electronics workshop.

(cue huge debate about the pro`s and cons of WD40)

If it is salvagable from WD40 etc and if the oproblem is due to damp
affecting the cone , is this being a 15 inch cone more likely to have
cone
distortions than a 12 inch for the same sort of damp?

If it`s a speaker from a reputable pro manufacturer, get it reconed at
Wembley Loudspeaker, if not, just replace it with whatever the customer
will pay for.


Intuitively I could expect a large cone to be more likely to have a
twisting
type distortion than a smaller cone, having a greater proportion of
unsupported edged length to surface area.


What part of a speaker do you consider to be 'unsupported edge length'?

Ron(UK)

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.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/