Orban OPTIMOD 8685, Operating Manual

Page: 163 / 357

OPTIMOD SURROUND PROCESSOR OPERATION
3-19
sired sound before you make further modifications at the Full or Ad-
vanced Modify levels.
Setting Preset Loudness Correctly for Dolby Digital Transmission
In sound for picture applications that use a Dolby Digital transmission channel to the
consumer’s receiver, you can use the 8685’s
L
OUDNESS
L
EVEL
meter as a reference for
adjusting a user preset’s loudness. This meter’s calibration tracks the 8685’s active
D
IALNORM
value, which is either the D
IALNORM
value in the active Setup (which ap-
plies to any preset whose
D
IALNORM
value is set to
G
LOBAL
)
or the
D
IALNORM
value in
the active processing preset if this value is not set to G
LOBAL
.
The controls to which the following procedure refers are described later in Section 3.
A) Make sure that the input reference level in the active preset is correctly ad-
justed (step 7 on page 2-11).
B) Make sure that the 8685’s active
D
IALNORM
value is the same as the Dialnorm
value you are transmitting to consumers’ receivers (step 10 on page 2-14).
C)
L
OCATE
to
A
DVANCED
C
ONTROL
, which is where you can access the controls re-
quired to complete the steps below.
D) If the AGC is turned on in the preset, adjust the AGC D
RIVE
control so that the
AGC is producing the desired amount of compression. We recommend 10 dB
or less with normal levels.
E) If the AGC’s idle gain (i.e. the gain reduction produced by the AGC when its si-
lence gate is on) is inappropriate, adjust it with the
AGC I
DLE
G
AIN
control.
If you are using a factory processing preset and you have adjusted the
input reference level correctly, there is no need to adjust the
AGC D
RIVE
or
AGC I
DLE
G
AIN
controls.
F) Adjust the
M
ULTIBAND
D
RIVE
or
2-B
AND
D
RIVE
control (depending on whether
the five-band or two-band structure is active) to produce the desired amount
of multiband gain reduction. We recommend about 5 dB for dialog at normal
levels.
G) If you wish to use the Loudness Controller: Set the
L
OUDNESS
T
HRESHOLD
con-
trol to –10 dB, which matches its threshold to the 8685’s active D
IALNORM
value. Then set the MB L
IMIT
D
RIVE
control to make the L
OUDNESS
GR meter
indicate 3 dB of gain reduction with dialog at normal levels.
You should see the L
OUDNESS
L
EVEL
meter peaking around 0 dB when the
L
OUDNESS
GR meter shows that gain reduction is occurring
H) If you do not wish to use the Loudness Controller: S et the L
OUDNESS
T
HRESHOLD
control to
O
FF
. Then adjust the
MB L
IMITER
D
RIVE
control to pro-
duce 0 dB peak indications on the
L
OUDNESS
L
EVEL
meter with dialog at nor-
mal levels.
Presets with the loudness controller off will produce wider source-to-
source loudness variation (as indicated on the
L
OUDNESS
L
EVEL
meter )
than presets with the loudness controller on. When the loudness control-