GUIDE TO INSTALLATION AND OPERATION
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| HCO-3901
ability to tightly follow the target output loudness. Using this preset, the program content will sound a little more
dense, while keeping most of the original program dynamic range.
•
Factory Standard –
The ALC applies moderate dynamic range compression on the audio program content. The
overall response time is also moderate, which allows the ALC to follow the target output loudness quite well. This
preset is well-suited for most types of audio content. It is the factory preset loaded when loading the card default
parameters.
•
Factory Heavy –
The ALC applies high dynamic range compression on the audio program content. The overall
response time is relatively fast, which improves the ALC ability to tightly follow the target output loudness. Using
this preset, the program output content will sound much more dense, less dynamic.
Five user presets are also available to save and load custom configurations of the ALC. These presets are labeled
ALC 1 to 5 but the user can edit the preset names via the “Edit Labels” button.
We
STRONGLY
recommend starting with the ALC factory preset (Light, Standard, Heavy) that is closest to the
desired objective, then fine tuning it to reach the desired goal. This will minimize the troubles that will likely be
encountered as many adjustments interact.
ALC Bypass
Checking this box bypasses the ALC processing, and the input channels pass through to the output unaltered.
Target Loudness
Sets the target output loudness. This value sets the
average
output loudness, which means that due to the program
dynamics, the output loudness will move around the selected target. With the ALC filter set to
None
, the target output
loudness ranges from -10 dBFS to -31 dBFS. With the ALC filter set to ITU-R BS.1770, the target output loudness
ranges from -10 LKFS to -31 LKFS.
Here’s the time-domain response of the ALC:
ALC Pre-Amp Level
A pre-amp stage is available in front of the ALC to compensate for programs having an input loudness out of the ALC
tracking range (very low or very high input loudness). The pre-amp level ranges from -20 dB to + 20 dB, in steps of 1
dB.
Fast Mode Response
The
Fast Mode Response
is optional and is enabled by checking the
Enable
box.
Limiter Threshold
Fast Mode Threshold
Transient Threshold
Transient Threshold
Gate Threshold
Output Target
Fast
Time
Transient
Time
ALC Response Time
Transient
Time
ALC
Response
Time
ALC
Response
Time
Freeze
INPUT
OUTPUT
