ORTF stereo recording was pioneered by the engineers at the French state broadcaster in the 1960s, and is defined as using a stereo pair of microphones with the capsules spaced 17cm apart, and at an angle of 110 degrees to each other.
A specially designed Rycote mounting adapter bar keeps the microphones at the correct spacing and angle for ORTF recording, and the Lyre suspension provide a solution that is extremely resistant to unwanted vibrations such as cable-borne and handling noise.