"David Satz" wrote in message
ups.com...
Norm, I assume you mean what Prof. Michael Williams calls the
"stereophonic recording angle" of a microphone setup. This is the
angle in the real-world recording situation which will just--more or
less exactly--seem to fill the span between two loudspeakers in
playback.

This angle varies considerably among different stereo microphone
arrangements. The ideal is to find a combination of miking distance
and (by selection of an appropriate setup) stereophonic recording
angle which will translate the actual angular width of whatever you're
recording into the angular width that you want in playback.

That doesn't mean that you always want to fill the distance between
the speakers completely. "The violin that ate New York" can be a
rather distracting effect, but it is also sad when most of the direct
sound sources in a recording seem to come from within a small range of
angles near to the center, as so often occurs when X/Y cardioids are
used by those who believe that 90 degrees is the ideal angle to set
between them. (It actually gives some enormously wide stereophonic
recording angle; the result is halfway between stereo and mono.)

At any rate, Williams' (and others') work can greatly reduce the
amount of trial and error that are needed when deciding on a
microphone setup for most simple stereo recording techniques. Once you
learn how to use his charts, they offer the big, previously missing
pieces of information for a lot of people. Highly recommended.

It's an excellent article, and it answers all my questions more than
adequately. I read an article by Bruce Babbit not too long ago in which he
shows experimental results of the apparent separation of 5 sound sources
compared to the actual separation of the same sources when recorded. I
guess the object is to make the recording sound as much like the original as
possible. It's interesting to note than the best results were obtained with
an ORTF placement having an angle of 110 degrees and a spacing of 17cm.

Also, the Sennheiser brochure for the MKH series has a short discussion of
stereo angles on the back 2 pages.

Thanks for your help.

Norm