This one is doubly interesting because someone wrote out a question and taped it to the first page:
What I found most interesting is that the booklet is old enough that it discusses the action of the horn. We no longer cover this in speaker design because there is essentially no more horn. Yes of course there are acoustic chambers but that old school exponential horn is long gone. This piece is detailed enough to distinguish between straight and curled exponential horns.
"What two changes of energy occur in a loud speaker?"
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