:51:04
which would modulate either left or right
:51:06
depending on the application
of the process.
:51:09
In density, you actually have
a photographic image
:51:12
that is gradients of grey to black, with
the modulations being darker or lighter.
:51:17
One of the problems with the system
is that in passages of no sound
:51:23
there is a very audible noise floor
that can be heard.
:51:27
In the mid-'40s there was quite a push
on in Hollywood sound departments
:51:32
to improve the quality
of their optical audio.
:51:35
And Western Electric came up with
a process known as a squeeze track
:51:39
to help noise reduction in this period.
:51:42
In the final mix, a shutter on
either side of the track negative...
:51:47
would open or close in sympathy
with the sound modulation.
:51:51
In this way, there was less
of the area of the track negative exposed
:51:55
in areas where there was silence.
:51:57
So if there was less scanning area,
there would be less system noise.
:52:02
The term "squeeze track"
can be explained
:52:04
when you look at the actual
soundtrack on the film.
:52:08
The shutter is narrower or wider,
constantly changing,
:52:11
as if it's squeezing the modulations.
:52:14
The volume of sound heard in the theatre
was dependent on
:52:17
how wide the soundtrack area was.
:52:20
So when you've got shutters
masking both sides of the track,
:52:23
you have an overall drop in volume.
:52:25
As a result, the theatre
was required to play the sound back
:52:29
four to six decibels louder than normal.
:52:32
Not only was Phantom's
engineering sophisticated,
:52:35
but its creative use of sound
was also far ahead of its time.
:52:39
The opera numbers were recorded by
multiple microphones in the auditorium.
:52:44
As a result, the sound is in perspective
to the ear as the camera is to the eye.
:52:49
If we're at the back of the hall
in a long shot,
:52:51
the sound has a very wet,
reverberant sound.
:52:54
If we cut to a closer angle on the stage,
the recording is much drier.
:52:59
If we're in a tier box or in the orchestra,
there's a medium perspective,