" wrote:

not much has changed in the last.... 35 years for solid-state excepting
around the edges.

You are JOKING !

You can't understand much about modern solid state design.

Even the true complementary pair was essentially unknown 35 yrs ago. And
that's for starters !

Speakers will use
better materials (sometimes) and tighter tolerances (sometimes), but
their essential function is unchanged. That the better materials and
tighter tolerances make them more efficient is a very good thing.

What about the use of modern materials to reduce cone break up ?

Not to mention in all aspects of engineering - the use of CAD / somputer
modelling to optimise designs.

Your knowledge is very weak.

Graham