I'm actually not so much interested in that technological stuff, more just recording and making use of the recordings, and now when I have found a good way to record, I think I'll skip those long explanations (that PDF article) about stereo and leave them for more rational people ...
Welcome Mr. Vurki!
I won't bore you with technicalities, but understanding one basic concept will help you in setting up any stereo microphone array.
Over simplified, it is this:
The closer the two mics are to each other, the wider the angle between them should be. Those two things are interdependent. If you change one, you usually need to change the other to compensate, keeping everything else equal. That’s really one of the most important relationships to consider when changing mic configurations while trying to figure out what works for you on a trial and error basis. The specific question then becomes, by how much?
A standard stereo configuration such as ORTF is just one specific set of spacing and angle combination that has been found to work well for typical recording situations using cardioid pattern microphones.
It’s easy enough to just use standard configurations like ORTF without understanding why or how they work, but you can also use that basic relationship to figure out many appropriate combinations of
mic spacing, mic angle, and mic pickup-pattern that also work and which might work much better. That’s what the Stereo Zoom business is all about. It explains how that basic relationship, along with some other variables encompass the whole alphabet of standard configurations (XY, ORTF, DIN-A, DIN-B, NOS, AB, etc.) as a continuum of possibilities between
close together but angled wide (which is XY), through
far apart but pointed the same direction (which is AB).
Does that make sense?
Obviously the further the mic elements are from each other, the more problematic mixing them will be (either in the media content, or in the reproduction of the media method).. Also consider that 3 to 1 ratio thing to account for comb filtering and other odd effects when the time of arrival is not matched between mics.
I don't mean to nit-pick and mean no personal offense, Shadow, but the above two statements are totally self contradictory and also not true in themselves. On top of that neither addresses stereo recording (where channels are kept separate), but instead concern electronically mixing multiple channels together. As I understand it, Good Mr Vurki is planning on both recording and playing back in stereo over loudspeakers. Sounds like this is for some type of public installation?
Although it is commonly misrepresented all over the web as applying to stereo recording with two spaced omnidirectional microphones, the 3:1 rule simply does not apply to simple two channel stereo recording at all. In fact, it’s nearly impossible to attempt to apply it to that scenario! (& that says something about how experienced many of the authors of seemingly authoritative information on the web really are, I don’t mean amateur forums like TS, but professional gear and information sites. Sorry, but widespread nature of mis-applying the 3:1 rule thing is one of my pet peeves)
The 3:1 rule is a set-up guideline for multiple microphones that will be mixed to the same channel. Think a line of back-up singers on stage, or a horn section, each with their own mic in front of them. It’s use is contradictory to the previous statement above because it emphasizes getting
as much space between mics as possible. Specifically, it recommends that the distance between each microphone be
at least 3 times or more the distance of the each microphone to the source it is supposed to pick up.
When mixing multiple microphones, there
might be problems if all the mics are either not in the exact same place or not far enough apart from each other. But it isn’t particularly obvious that could cause problems to someone who doesn’t know why it might, and on top of that it might not! It’s the pretty close to not far enough apart region that can be
potentially problematic, but that only applies when mixing the mic feeds to the same channel (technical point: before someone claims that mixing to stereo is different, I’ll point out that panning multiple mics across a stereo buss
is mixing them, just with different ratios to each side).
Again, none of this applies to two mic stereo recording and stereo playback. I just want to correct some misunderstandings stated in the post above.