The ORTF stereo technique uses two first order cardioid microphones with a spacing of 17 cm between the microphone diaphragms, and with an 110° angle between the capsules.
The ORTF stereo technique uses two first-order cardioid microphones with a spacing of 17 cm (6.7 in) between the microphone diaphragms and with an 110° angle between the capsules. The intention of this technique is to reproduce 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.
The ORTF stereo technique provides the recording with a wider stereo image than XY stereo and still preserves a reasonable amount of mono-information.
Care must be taken when using this technique at larger distances; the directional microphones exhibit proximity effect and will result in low-frequency loss. You could add low frequency with an equalizer if needed.
Suggested microphone kits and accessories d:dicate™ ST2011A Stereo Pair with 2011A Cardioids d:dicate™ ST4011A Stereo Pair with 4011A Cardioids SB0400 Stereo Boom, Modular UA0837 Stereo Boom DUA0019 Spacer for Stereo Boom, 19 mm (0.75 in)