These two Panning Types will only become available when a Virtual Room is set to be virtualising a stereo speaker arrangement (see section 6.52) - they are pan laws that are derived from widely used dual microphone techniques for rendering stereo imaging from an omnidirectional scene.
AB Panning simulates the recording of the sound scene by a pair of spaced cardioid microphones, pointing laterally at azimuths +/- 55 deg. (elevation 0), with a distance of 17 cm between the two capsules. Also known as ORTF.
XY Panning simulates the recording of the sound scene by a pair of microphones in an XY coincident configuration.
★ The aim is to get the same stereo flavour as these dual microphone tracking techniques. Try them on close miked sources or any mono source, to get a realistic stereo image.