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-24's logo facing the center of the
performance, the mic is positioned for X-Y
recording. Rotating the SF-24 counter-clockwise by
45
¼
positions it for M-S recording.
By inserting your SF-24 with the logo in the left slot
of the RSM-24 shock mount (see Using the RSM-24
Shock Mount, page 9), then facing the shock mounts
logo directly at the center of the performance, the
microphone will be rotated 45
¼
counter-clockwise
and correctly positioned for M-S recording. With the
SF-24 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 element is at 90
¼
to the performance
and is the “side” microphone. If the microphone is to
be mounted upside down, make the proper
adjustments in your wiring orientation.
If the outputs of the mid and side elements are made equal using gain controls, the stereo pickup
will be similar to that of two microphones placed as a Blumlein X-Y pair, delivering a wide
stereo image. As you reduce the level of the “side” element, the width of the stereo image will
narrow until, with the side element turned all the way down, you have just the “mid” element
panned center and giving a mono pickup.
If the outputs of the “mid” and “side” elements are recorded on separate tracks, the electrical
connections shown in
Figure
3
can be made at the mixer outputs and the adjustment of the stereo
separation can be done during mixdown, rather than during the actual recording.
Space does not permit a fuller discussion of the M-S intensity stereo format, first described by
Alan D. Blumlein over 50 years ago. We suggest the following reading on the subject:
Figure 2
16
