NatureRecordists,
Walt Knapp raises some very interesting thoughts when he says:
"This, I assume is a good part of the reason for the graphs of real
parabolics (of older varieties now, shown in Sten's paper) to have such
a fall off compared to theory. I expect a lot of the older parabolics
were using mics with pretty big diaphragms."
Yes and yes. He also says:
"With the much smaller diaphragms now used this is probably not as
much a factor?"
The "topping out" simply occurs at a higher frequency, but still very much =
within the spectrum of interest. He also says:
"Perhaps should make it clear that we are still talking considerable gain
even if it levels off."
Amen! Noiseless amplification nearly equal to the ratio of the reflector a=
rea to the microphone diaphragm area, which typically equates to hundreds (=
read 20dB) to thousands (read 30dB). And he adds:
"Of course the Telinga is different here too. With it's boundary mic,
multicapsule approach. Wonder how the math looks for that?"
Food for thought, but let's not forget that the boundary effect is also due=
to reflection and consequently is frequency-dependent for a finite-sized b=
oundary plate. Frankly, I don't see how the pressure-doubling at a perfec=
tly reflecting plane could have application in any practical-sized
parabolic reflector system for audio frequencies. Maybe Klas cares to
comment?
Good recording,
Randy
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Randolph S. Little <>
111 Berkeley Circle, Basking Ridge, NJ 07920-2009
Phone: (908)221-9173 Fax: (908)630-0871
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