A little theory
Spatial location in a stereo pair comes from 2 differences. The first is differences in sound volume Left speaker to right. A 15 to 20 dB difference in volume will put the image in one speaker. A 6 dB will put the image about half way between the center line and the louder speaker.
The second way is by time differences. A 1.2 to 1.5 mS delay from one speaker to the other is enough to make it appear to dome from the speaker that first sounds.
With any coincident pair (XY, MS, Blumlein) there is no time difference between the mic's so sound level decides the image placement. You would want to record these mics with full left-right panning so as to capture as much of the stereo image as possible. Then in mix you can blend them to get the image placement you want. (IMHO)
With any spaced pair (typically omni's but can be any pattern) image localization is due to time differences between the mic's. The greater the spaceing between mic's the greater the stereo spread.
Then there is the near-coincident-pair (ORTF,NOS, DIN etc) where directional mic's are pointer at angles to each other and spaced a few inches apart. This gives both level and time differences which can add to a sense of ambient warmth or air.
In all 3 mic configurations the original capture is best served by not blending the signals (pan hard left and right) but allowing the mic configuration to do the work. And if needed to get the souund that you want blend them in the mix.
It should be noted that in any configuration with a time delay in it when panning you may introduce conflicting information. for example if the left channel is louder but delayed from the right you will hear a diffuse unlocalized (like being out of phase) sound. Volume says it is on the left and time delay says it is on the right
REgards, Ethan
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