<<My thinking (and questioning) was that the two L an R cardiods say
at 90-110=B0 might record stereo ambiance better than M/S ?>>
To clarify a bit, decoded MS provides EXACTLY the same stereo field
as XY (coincident 90=B0 cardioids).
<<I wasn't necessarily concerned that I was technically recording M/S
style, but rather attempting to get a better stereo version of the
real world.>>
It's the same, not better. The possible advantage to using a pair of
cardioids is you can utilize the several other near coincident
techniques, such as ORTF & NOS.
<<By mixing the third channel (possible with the SD302 mixer/preamp)
as "Center" and using a super cardiod I would get the reach and be
able to select the main target better, while still capturing good
stereo and ambiance with the L and R mics ?>>
Adding a third mic to any of the tried & true stereo techniques
merely adds more mono information, at the expense of stereo spread &
a certain amount of additional phase muddiness. There is already
sufficient mono included in coincident & near coincident techniques.
As far as "reach", this is a bit of a myth. Directional microphones
don't reach any further than nondirectional mics. They merely
attenuate more off-axis information. You can derive the benefit of
this directionality by incorporating hypercardioids or supercardioids
into XY or ORTF arrays, or use a shotgun type mic in an MS set up.
Additionally Neumann has a stereo shotgun mic for film production
applications.
<<I think I understand the issue of the phasing of the L and R mics,
but wouldn't that still be the case even if you were only using two
mics in a standard stereo arrangement ?>>
You could get close to creating a figure with two back to back
hypercardioids if they were side address mics. End address mics would
get in each other's way & skew the pattern. Also, be aware that a
figure 8 is not two cardioid patterns back to back, but closer to the
effect of two hypercardioids back to back. There is much more off
axis rejection in figure 8 & hypercardioid than with cardioid. Since
MS recreates the same characteristics as XY it is important to
maintain phase coherency in the horizontal plane, so the capsules
have to be right on top of one another.
<<I will go out and trial this arrangement but without the recording
experience I might either be reinventing the wheel or wasting time by
doing it the wrong way.>>
If you get a recording you like there is no wrong way. If you're
trying to obtain true stereo perspective which recreates relatively
closely the experience of being in the soundscape when played back
over speakers, these techniques were discovered & refined pretty
thoroughly over the last half century.
Scott Fraser
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