Zoom XYH-6 Adjustable X/Y Capsule
The X/Y miking technique is optimal when you want to cover a wide area and still capture sound sources in the center with clarity and definition, making it great for all types of live stereo recording.
The XYH-6 X/Y capsule adds two matched high-quality unidirectional microphones to your H6. This kind of microphone is most sensitive to signal coming from directly in front, and less sensitive to signal coming from behind or from the sides; in technical terms, they are said to utilize a cardioid polar pattern. These mics have the largest diaphragm size (0.579" = 14.6mm) of any ever available on a portable recorder.
As shown in this illustration, the angle of the two mics can easily be changed from 90 degrees to 120 degrees for a wider stereo image (US Patent 8184815).
Playing back stereo X/Y tracks in mono results in a fuller sound than you would get with one microphone, but if mono compatibility is critical (for example, in television production), the Mid-Side (MS) mic technique can be a better choice.