Orban Optimod-PC 1101, Operating Manual

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2-28
INSTALLATION ORBAN MODEL 1101
c) D
ITHER
= I
N
.
d) F
ORMAT
= AES.
D) Click the O
UTPUT
L
EVELS
tab and set the Digital 1 S
IGNAL
R
OUTE
F
ROM
drop-
down to P
ROCESSOR
M
IXER
P
OST
-L
IMIT
.
This applies stereo enhancement, equalization, AGC, 2-Band or 5-Band
compression, loudness control, and look-ahead peak limiting. No other
output source will work correctly with Dialnorm.
E) Adjust the D
IGITAL
1 O
UTPUT
control to set the desired peak headroom in units
of dB below full-scale.
Setting Output Loudness in Dolby Digital transmissions: When you
have assigned the Dialnorm R
EFERENCE
O
UTPUT
to the 1101 digital output
driving the Dolby Digital channel, the DO 100% control for that output
no longer adjusts loudness. Instead, it sets the 1101’s maximum peak
output level with respect to 0 dBfs, which allows you to compensate for
transmission channels that introduce peak overshoots. For example, if
you lower an output control from 0 dBfs to –2 dBfs, the 1101 automati-
cally reduces the gain following its peak limiter by 2 dB and simultane-
ously increases the drive into the look-ahead limiter by 2 dB. Hence, the
average output level does not change but the maximum peak output
level is constrained to –2 dBfs
1
. This unconventional arrangement results
from the 1101’s handling of Dialnorm—if you have set the D
IALNORM
con-
trol correctly on the 1101, you can change the output level control freely
without causing your loudness to be incorrect with respect to other
Dolby Digital transmissions.
To set the output loudness, adjust the D
IALNORM
value or adjust the MB
L
IMITER
D
RIVE
control in the active processing preset. Both methods cause
1101’s Output Level meter indication to change.
In a Dolby Digital transmission channel, the D
IALNORM
value is the same as
the “target loudness” as measured by an ITU-R BS.1770-2 loudness meter
in units of LKFS (ATSC Rec. A/85) or LUFS (EBU Rec. R128). Your
OPTIMOD-PC contains such a meter. To comply with these standards,
D
IALNORM
is customarily set to –24 in the United States and –23 in the EU.
Setting D
IALNORM
to the target loudness is the preferred way to comply
with these recommendations and, in the U.S., with the CALM Act.
.Adjusting D
IALNORM
changes output loudness without changing the indi-
cation on the 1101’s CBS or BS.1770-2 loudness meters or the amount of
gain reduction in the loudness controller. The peak limiter’s gain reduc-
tion will change. This is the preferred method if the 1101’s loudness con-
troller is active because it has the smallest effect on the sonic texture of
the 1101’s audio processing.
1
If this causes large amounts of gain reduction to occur in the look-ahead limiter,
the average level will decrease somewhat. However, this will only happen with
pathologically high settings of Dialnorm and will never happen at the settings of
Dialnorm typically used in broadcasts (–24 for ATSC Rec. A/85 and –23 for EBU Rec.
R128).