Handbook for Sound Engineers

Microphones 549

from the TV screen is considered to be five times the
screen diagonal, at which distance the line structure of
the TV image can no longer be resolved by the human
eye. The resulting minimum observer distance is there-
fore 11 ft (3.3 m) and the two loudspeakers should be at
least 12.5 ft (3.8 m) apart. This is certainly not realistic
for television viewing.
The sound engineer must take into account that the
reproduction will be through loudspeakers right next to

the TV screen as well as through hi-fi equipment. If, for

instance, the full base width is used during the sound

recording of a TV scene, an actor appearing at the right

edge of the picture will be heard through the right loud-

speaker of the hi-fi system and sound as if he is far to

the right of the TV set. This will result in an unaccept-

able perception of location.

The viewer must be able to hear realistically the

talker on the TV screen in the very place where the

viewer sees the talker. To achieve this goal, German

television proposed to combine a unidirectional micro-

phone for the recording of the actors with a figure

8microphone for the recording of the full stereophonic

basic width.

This recording technique utilizes a figure-eight

microphone suspended from the boom in such a way

that it maintains its direction when the boom is rotated

while a second microphone with unidirectional pattern

is mounted on top and follows the movement of an actor

or reporter, Fig. 16-126. To make sure that the direc-

tional characteristic of the moving microphone does not

have too strong an influence and that a slight angular

error will not lead to immediately perceptible direc-

tional changes, the lobe should be somewhat wider as

with the customary shotgun microphones in use today.

It is now possible to produce a finished stereo sound-

track on location by positioning the microphones in the

manner of an M/S combination. The level of the figure

8 microphone can be lowered and used only for the

recording of voices outside of the picture, ambience and

music. This microphone should always remain in a

fixed position and its direction should not be changed.

The S-signal generated in this way must be attenuated

to such a degree that the M-signal microphone will

Figure 16-124. Stereo pickup pattern of the Shure VP88 in
the H position. Courtesy Shure Incorporated.

Figure 16-125. Exposure of X and M microphones to 0q
pickup.

Mid

Side

B. Pickup pattern of the system.

A. Relative levels of the mid and side microphones.

Figure 16-126. Stereo boom microphone using Sennheiser

MKH 30 and MKH 70 microphones. Courtesy Sennheiser

Electronic Corporation.