Stereo Recording Techniques

XY configuration is one of the easiest ways to record in stereo. It refers to two identical directional microphones arranged so that their grilles are close to each other angled 90-degrees from each other panned left and right. XY microphones are suspended 2-3 feet above the conductor.

Blumlein Arrays are a type of Coincident Pair set up similar to XY but instead of using a cardioid pickup pattern, they use a pair of "Figure 8" microphones. The purpose of this array is to produce both a stereo image with a strong center while capturing the room noise and ambience due to recording in all directions.

AB recording techniques use two identical microphones placed several several feet apart aimed straight ahead towards the sound source. You can use different pick up pattern mics but omnidirectional is the most common type of microphone used.

The Decca Tree, is a triangular array typically used for recording orchestral recordings. It features three omnidirectional microphones placed on a custom stand suspended 10-12 feet above the conductors head. It uses two omnidirectional microphones spaced out evenly with the third placed in the front usually at a ratio of 2:1. These can be scaled depending on the size of the orchestra. 

ORTF is the most common type of Near-Coincident recording technique. It uses two cardioid microphones angled 110 degrees away from each other. This type of recording is widely used as it closely resembles the way the human ear hears. 

NOS stands for Nedelandshe Omroep Stichting, is a type of stereo recording technique that uses two cardioid microphones spaced 11.8 inches apart and angled 90 degrees away from each other.