Royer Labs SF-24V - Manual (Page 16)

Specialized Stereo Recording Techniques
Classic Blumlein Technique
For many years, “coincident” microphone setups have been widely used for picking up sounds in
stereo as naturally as possible. The “Blumlein” technique, named for A.D. Blumlein, involves the
use of two figure-eight microphones positioned as in
the sketch (see Figure 1); so that one faces left and
the other faces right, at an angle of 90º (i.e., each
displaced 45º from center).
Each microphone ultimately feeds one speaker in a
stereo system, and due to the directionality of the
microphones, the result is a very well defined stereo
image on playback. For classical music, particularly,
the reproduction can be very satisfying.
The SF-24V stereo microphone is two identical
ribbon microphones in just this Blumlein orientation:
if the microphone is placed in front of the
performance, with the Royer logo facing the center of
the ensemble to be recorded, the microphone will
give a stereo recording as per the Blumlein technique.
Because of the togetherness of the SF-24V’s ribbon
transducers, sound will arrive at both ribbon elements
at the same time. This means that the two channels
can be summed to mono with no comb filter effects, and room reverberation (undesirable in
mono) is cancelled to a surprising degree.
For the sake of clarity, engineers commonly refer to similar stereo miking with cardioid mics as
“X-Y.” When figure-8’s are used, it is more commonly referred to as “Blumlein” recording.
Mid-Side (M-S) Technique
In the early days of stereo radio broadcasting, the Mid-Side recording technique was developed
to allow for 1) simultaneous stereo and mono feeds from the same mic array and 2) electronic
manipulation of the width of the stereo image. In M-S recording, one mic faces sideways, one
faces forward as shown in Figure 2, and they are connected as shown in Figure 3.
With the SF-24V's logo facing the center of the performance, the mic is positioned for X-Y
recording. Rotating the SF-24V counter-clockwise by 45º positions it for MS recording.
By inserting your SF-24V with the logo in the left slot of the RSM-24 shock mount (see Using
the RSM-24 Shock-mount, page 7), then facing the shock-mount's logo directly at the center of
the performance, the microphone will be rotated 45º counterclockwise and correctly positioned
for M-S recording. With the SF-24V in a vertical position, cable end down, the upper ribbon
element faces the center of the performance and is the “mid” microphone, and the lower ribbon
Figure 1
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