TC Electronic DB4 MKII - Manual (Page 69)

ALC 5.1
English Manual 65
Preset Title
The Main page of any algorithm in DB4 and
DB8 displays the title of the current preset. Click
on the Name field to edit a preset title, and Store
the changes if you wish to keep them.
Input Level
Input gain applied to all 5.1 channels before
loudness detection or processing is applied.
The range of the Input Level parameter is -18 to
+18 dB. Because DB4 and DB8 use 48 bit pro-
cessing, a positive Input gain does not create
overload, even if the input signal is already at
full scale.
Delay
Time alignment of all 5.1 channels at 24 bit
resolution. The delay function makes use of si-
lent update technology so adjustments may be
performed live on air. Minimum latency through
ALC5.1 is 1 ms. Additional delay of up to 1 sec
may be added using this parameter.
Delay Unit
Sets the unit used to display delay time, frames
or milliseconds (30 fr, 25 fr, 24 fr, ms).
ALC5.1 algorithm – setup page
ALC5.1 algorithm – setup page, showing set-
tings according to ITU-R BS.1770.
Channel Weighting
Sets the weighting of each Main channel to the
loudness measurement. BS.1770 specifies the
front channels to be set at 0.0 dB, and the sur-
rounds at +1.5 dB. However, it’s possible that
more ideal compromises may be found. To have
the combined result stay the same, all channels
should sum at +3.0 dB. (For example, all chan-
nels except for Center at 0.0 dB, and Center
at +3.0 dB. Or L/R at 0.0 dB, and all others at
+1.0 dB).
LFE Weighting
Determines whether the LFE channel should
contribute to the loudness measurement or not.
According to original BS.1770, the LFE should
not contribute. However, the debate is on, and
the recommendation might change. If you find
that commercials start using unexpectedly high
LFE level, you may wish to bring LFE into the
equation. The ALC5.1 algorithm enables you to
keep flexible on this issue..
LFE Process
Determines if LFE gain follows the Main chan-
nels or not.
ALC5.1 algorithm – ALC page
ALC5.1 algorithm – Automatic Loudness Cor-
rect page, set for using the BS.1770 loudness
measure.
Settings shown are suitable for a static Dial-
norm value of between -24 and –26 in AC3
transmission. For SDTV and Mobile TV feeds, a
higher Target Level should normally be chosen.
Target Level
Sets the Loudness Target, aimed for by ALC5.1.
The unit is “LFS”. When “ITU-R BS.1770” is
selected as loudness measure, LFS denotes
“LKFS”, which also is the same as “LUFS”. See
Fig 7, parameter no 1. For normal broadcast, the
value should typically be between -18 and -24
LFS. Note that the distance between this value