Thank you for your responses.
I am currently using a electret cardiod microphone and this undoubtedly
helps. I will look into ways to tighten the pattern. I have also performed
some preliminary experiments outdoors, but the ambient noise was too loud and
my extension cords limited such that the results were somewhat ambiguous. If
I get a chance, Iwill try to take some measurements in an anechoic chamber
which will settle this issue once and for all. And, I will be happy to pass
it along, once determined.
I would also be happy to continue the acoustics side of this conversation by
e-mail or on the acoustics site. How do I find this site?
Thanks again for your responses.