Stereo mic. S502 Stereo microphone combines a pair of matched cardioid capsules in an ORTF arrangement. The ORTF stereo technique uses two first order cardioid microphones with a spacing of 17 cm between the microphone diaphragms, and with a 110° angle between the capsules. This technique is well suited for reproducing stereo cues that are similar to those that are used by the human ear to perceive directional information in the horizontal plane. The spacing of the microphones emulates the distance between the human ears, and the angle between the two directional microphones emulates the shadow effect of the human head.