52
Dolby
®
CP750 Digital Cinema Processor Manual
Aligning the Auditorium
4.
Click
Force
PL
Cut
to
activate
the
Dolby
Pro
Logic
subwoofer
and
adjust
the
Cut
slider
to
achieve
an
average
level
of
0
dB
as
indicated
on
the
spectrum
analyzer.
The
Pro
Logic
subwoofer
is
always
set
to
match
the
level
of
the
center
channel
and
to
act
as
bass
extension
during
Pro
Logic
or
Pro
Logic
II
playback.
6.7.3
Subwoofer Speaker Polarity Check
To
check
subwoofer
speaker
polarity:
1.
Click
Center
Channel
Gen
on
the
Channel
Tune
tab
to
generate
center
‐
channel
pink
noise.
2.
Choose
a
Filter
Frequency
to
select
the
crossover
point
between
your
main
speakers
and
the
LFE.
Use
50
Hz
if
your
main
speakers
are
full
spectrum.
Use
100
Hz
otherwise.
3.
Click
Phase
Invert
and
watch
the
behavior
of
the
filter
frequency
band.
There
should
be
a
level
decrease
as
soon
as
you
click
Phase
Invert
.
If
you
do
not
see
a
decrease,
the
polarity
of
the
subwoofer
wiring
is
incorrect.
Reverse
the
subwoofer
speaker
wire
connections
to
correct
it.
The
subwoofer
polarity
always
resets
to
normal
after
completing
this
check.
Phase
Invert
is
a
temporary
setting
for
this
test
only.
6.8
Final Sound Check
Follow
these
steps
to
do
a
final
equalization
check
of
the
auditorium.
1.
On
the
Room
Levels
tab,
click
Rotate
under
Signal
Generator
Enable
.
2.
Choose
Signal
Mode
Pink
Noise
to
start
pink
noise.
Pink
noise
is
sent
to
each
channel
in
turn,
holding
for
five
seconds
at
each
channel.
3.
Go
to
the
auditorium
and
sit
two
‐
thirds
of
the
distance
from
the
front
speakers
to
the
rear,
and
at
the
side
‐
to
‐
side
center
of
the
room.
All
channels
should
sound
equally
loud
and
have
similar
frequency
response
as
the
noise
rotates.
An
SPL
meter
can
be
used
to
confirm
accurate
and
equal
level
settings.
6.9
Nonsync Level Adjustment
You
can
adjust
the
Nonsync
level
on
the
Nonsync
Input
tab.
1.
Click
the
Nonsync
Input
tab
to
open
it.
2.
Play
a
CD
or
other
audio
source
on
your
nonsync
device
and
adjust
the
slider
in
the
setup
software
for
the
desired
level
in
the
theatre.
If
possible,
select
a
recording
that
has
a
natural
ambience,
such
as
an
orchestral
work.
Note:
Unlike
the
different
levels
used
during
alignment,
the
rotating
pink
noise
is
set
to
85
dB
for
all
channels
during
this
test.
Pressing
<Enter>
stops
the
pink
noise
from
moving
to
the
next
channel.
Pressing
<Enter>
again
resumes
pink
‐
noise
rotation.
Содержание CP750
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