To monitor sound with the
earphone without running the
camera, plug in earphone and
depress monitor button (electric
eye tester button). The sounds
reaching the microphone will be
heard while the button is held
depressed.
TIPS FOR BETTER SOUND
MOVIES
You may have heard of people who
li ve near the elevated tracks and
are able to conduct a conversation
in normal tones as a train passes
by with deafening roar, while their
visitors cannot hear a word. Or
you may have taken part in a
conversation while someone was
watching TV in the room. Usually
the people conversing are not
aware of the TV sounds, while the
TV watcher is oblivious of the
conversation. The above are
examples of the human mind's
ability to be selective, to hear only
what it wants to hear, at the
exclusion of other sounds also
picked up by the ear. In the case
of the train this takes considerable
conditioning, while the TV
example is quite common.
The microphone of your sound
camera is like the human ear: it
will pick up all sounds reaching it.
However, it is not backed up by a
selective human mind. Remember
this when you plan your sound
movies. For clean, clear sound in
your movies you have to make
sure that only clear, clean sound
is allowed to reach the
microphone. The most common
causes of unsatisfactory sound
recording are background noise,
more than one sound source,
microphone placement and poor
location. Let's discuss these one
by one and see what can be done
about them.
Background noise
Background noise or ambient
noise level (as it is often called) is
the sum of sounds that exists at
the time of sound movie making,
in addition to the sound intended
to be recorded. A surprisingly
high level of background noise
can remain unnoticed by the
moviemaker due to his mind's
ability to ignore undesirable
sounds.
Checking the sounds reaching
the microphone with the earphone
is the best way to detect
background noise. With the
earphone all sounds reaching the
microphone will be heard as the
earphone represents a single
sound source, here the selectivity
of the human mind does not
apply.
What can you do about the
unwanted background noise.
Before we can answer, the
function of the automatic gain
control must be described.
The function of the automatic
gain control is to provide the
soundtrack recording head with
an optimum input that will result
in the best recorded sound
quality. To achieve this, the
control seeks out the loudest
sound that reaches the micro-
phone and adjusts it to optimum
recording level. This works fine
when the loudness of the to-be-
recorded sound is far above the
level of the background noise
(ambient noise level). As the
automatic gain adjusts the main
sound source, it also adjusts the
background noise in proportion,
so that the background noise will
be barely heard in the recording.
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