Ortf Stereo - Schoeps UMS 20 User Manual

ORTF Stereo

ORTF Stereo
(green markings; Fig. 2)
Microphones: two MK 4 cardioids.
Looking from the side of the rail with the
colored dots, angle the right clamp as far as it
will go and the left clamp 45° to the middle
of the rail (i.e. forwards). Insert the micro-
phones into the clamps up to just below the
SCHOEPS logo. Now angle the left clamp until
the microphones are about 3 mm apart. The
middles of the capsules are now 17 cm apart.
The angle between the microphones is 110°.
Variations – Personal Settings
The UMS 20 can be used for a great deal
more than just ORTF and X/Y recordings. You
can make equally good recordings by choos-
ing different angles and distances between
the microphones than the standard settings
described above. Here is a brief guide:
One of the essential aims when making
stereo recordings is to reproduce the pickup
angle α (s ee F ig. 8a) in an area of 60° dur-
ing playback through louds peakers (s ee
F ig. 8b). T he crucial parameters for achiev-
ing this are:
1. the directivity of the microphones used,
2. their distance from the sound source,
3. the angle ω that the microphone axes
cover together, and
4. the distance d between the membranes of
the microphones.
How to Determine the Parameters
1. Since the UMS 20 holds the microphones
so close together, its use is practically limited
to techniques that use directional microphones
only, such as cardioids, supercardioids and
figure-8 (bidirectional) microphones.
2. The distance a of the microphone from the
sound source is especially important: The dis-
tance influences not only the stereo image,
but also the sound, since it defines the ratio
of direct to reflected sound (diffuse sound).
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Area to be recorded
(e.g. orchestra or band)
main stereo
axis
α
ω
Fig. 8a
Stereophonic recording angle α and axis
angle ω ; all direct sound sources should be
within the stereophonic recording angle.
listener
Fig. 8b
The stereophonic recording angle α from
Fig. 4a is mapped into an angle α ' of 60°
during loudspeaker playback..
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a
d
α '=
60°