The Josephson Jecklin Disk is a stereo microphone baffle designed to be used with a pair of omnidirection microphones.
Stucture of the OSS arrangement (Jecklin disc):
Two sound pressure microphones are arranged at a distance of 165 mm. This distance results in the correct delay time difference between the two channels. The two microphones are separated by an acoustically muffled disc of 300 mm diameter. The effect of this disc is as follows: as the frequency increases, the two microphones are more and more separated. Below the value of approximately 200 Hz, the two microphones record the same. The acoustic muffling of the disc results in a frequency response difference of the two channels depending on the angle of impact of the sound. In addition, there is a sound diffraction around the disc rim which is dependent on frequency and angle. The result of these clear acoustic conditions is a natural sound and a real spatial acoustic pattern. The simultaneous reproduction of the spatial sound distribution by the two loudspeakers cannot be achieved by any other recording technique.