> The same photo is in this group of echo locators:
>
> http://tinyurl.com/28wrr4y
Rob & Greg,
Thanks for the links. I loved the collection in the one above,
especially the woman in a straw boater (an impedance problem?) but
none of them had the elegance of a cut down cardboard box. :-)
There's a lot of baloney in acoustics and also people get hung up on
exponential horns and parabolic reflectors. What works best for
recording is a conical horn and a spherical reflector. BTW the giant
reflectors in Kent built to listen for German bombers are now
preserved as historic buildings.
I've just ordered a few discontinued mini lapel mics from Canford
Audio
at a knock down price and next step is to put two in a plywood
Brinihorn. This is equivalent to two conical horns which have a "soft
focus" which is what we need. This is the problem with parabolics,
they focus finely at high frequencies but are no better than a baffle
at low. You need to keep them aimed at a bird, as with binoulars, and
they cannot, even in pairs, produce a stereo spread.
The locators in the web page would have a very narrow angle and it
would
have been difficult to locate an unknown source, but they would give
an accurate horizontal angle if you got the exact vertical
lineup. One eliptical horn would have probably done better.
Student question: would you put the long dimension vertically or
horizontally? I've seen hi-fi tweeter horns mounted the wrong way up.
David
David Brinicombe
North Devon, UK
Cogito cogito ergo cogito sum - Ambrose Bierce
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