I must be nuts to bring this up again, but I still have some burning
unanswered questions -so here is one.
Regarding the focal point (and I know it is not really a point), what
is the ideal distance inside the rim. I am hearing different opinions.
One from a Cornell page suggests if the mic is positioned inside the
dish there would be a distortion from cavity resonance (or something
like that) off the sides of the dish.
Conversely, a few of this group suggest a standing wave at the rim
opening would cause distortion, so the mic is best put inside the dish
somewhere below the level of the rim.
Is the standing wave only exactly at the rim level or does it extend
somewhat into and out-of the dish? If so how far each way? Would the
optimal position of of the focus be at a certain ratio of the dish
depth?
If anyone can bring a little more light to this problem or steer me in
the right direction, I will be sincerely grateful.
John Hartog
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