"Most transducers do not have radiating surfaces which are rigid pistons and so it would be convenient to generalize the approach shown above to consider non-rigid piston behavior... [calculus calculus calculus... Duke doesn't speak calculus... reverting now to English on page 75]... The above result can be greatly simplified for the case where the source is axi-symmetric but still not a rigid piston - by far the most common situation... [less calculus]..."

I can't comment on how complete Earl's mathematical model is. That would be like me critiquing subjunctive tense conjugations in ancient Summarian poetry.

Duke