To amplify and clarify a bit on this:
<<There are many ways to obtain stereo, one way is to use two
microphones with the same pickup pattern.
These can be either omni or cardioid microphones.>>
They can be any of a number of other patterns as well, hypercardioid,
subcardioid, & figure eight being common.
<<Omni's can be used 'spaced' or with some barrier
between them.>>
Also known as "AB" stereo, with "near-spaced" & "wide-spaced" being
the principle variations on the theme.
<< While cardioids are often used in a
'crossed pair' configuration sometimes referred to as
'coincident pairs'.>>
The "near-coincident" approach is increasingly popular, as it
incorporates time-of-arrival information as well as amplitude
differentiation between channels. Coincident miking makes use only of
amplitude information for directional cues. Near coincident places
the mics at approximately the distance between human ears, & is
typified by the ORTF & NOS standards. Any number of hybrid techniques
between coincident & near coincident are also valid, depending on the
width of the intended stereo field & the distance to the intended
subject.
<<The other method for recording stereo is where you use
two microphones with very different polar diagrams, MS
stereo. This is where a figure of 8 and an omni
microphone are used.>>
Generally cardioid is used as the mid microphone in MS technique,
although hypercardioid also is used. With a cardioid mic the decoded
MS output is identical to the output of an XY coincident pair, so MS
is really just a subset of the coincident approach.
<<Finally there is the single point stereo mic something
like the Shure VP88 which I know some people use.>>
The Shure VP88 is an MS array. Various other stereo mics provide XY,
almost XY & Blumlein configurations in a single point body.
Scott Fraser
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