The fig.8? Mainly for MS (and MSM) recording but it has different
applications.
Using MS for atmos can be deceiving since it is a coincident pair but
sometimes can be the only way. It can be used on a boom to start with
(although it is pretty sensitive to handling noise and you have to
boom like an angel) but otoh you better lock the mics and stay away
for a good atmo.
MS is used a lot in documentary because you get both a good
directional pickup and a stereo portrait of the scene. It also makes
the recording a bit more tolerant to other sounds because in stereo
you can "follow" a voice much better.
It also let other characters enter the scene very naturally wich is
great in docus or certain kind of naturalistic films.
But it's not easy to operate. Not only because of the handling noise,
but to preserve spatial consistency: you should always keep the pair
horizontal and that's not always practical (and can be annoying and
frustrating) You can invert the pair (and anotate it for post) so L
and R are interchanged.
Be aware not all fig. 8 are truly bidirectional. The MKH 30 is, the
800 (and the mic I posted the link of) is not, because it uses two
oposed diafragms instead of a bipolar one.
Just search for MS recording / MS matrix / Alan Blumlein 1930s...!
