mbho Schneider disc for OSS recording

Beschrijving

What you are looking at is not an extraterrestrial spacecraft
but a “Schneider disc”. The Schneider disc is a
variation of the Jecklin disc developed by J?rgen Jecklin
for his stereo microphone technique known as Optimal
Stereo Signal (OSS). The idea behind OSS is to
use a pair of spaced omnidirectional microphones
approximately 6 inches apart (roughly the distance between
the human ears) with a disc placed in between the
spaced pair. The disc is covered with a thin layer of
foam intended to absorb high frequencies – thus improving
stereo separation between the microphones. The
difference between the two types of discs is the foam
sphere at the center of the Schneider disc, which reduces
the amount of high-frequency energy reflected from
the disc, and results in an increase of stereo separation.
Below approximately 200 Hz, the Schneider disc has
little (if any) effect on the stereo signal because the
audio wavelength is large enough to bend around the
disc, equally reaching both microphones. However as
frequency increases above 200 Hz, the Schneider disc’s
foam sphere increases stereo separation between the
spaced pair.

Jecklin + Schneider disc for OSS recording,
recommended microphones:
2 x MBP 648 preamps & 2 x KA 100 DK capsules
The Schneider disc may be used in OSS technique for
stereo recordings of orchestral or chamber music, as
well as for stereo micing of solo instruments. In order to
properly implement OSS, the microphones should be
identical, omnidirectional and should be set for equal
output to avoid unbalancing of the stereo image (this can
be checked using headphones). For the best balance
between direct and room sound, the Schneider disc
should be located at the distance from the source where
the direct sound and the diffuse sound from the room are
at equal strength. This distance is known as the diffusefield
distance and can be located by careful listening.