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VP-8IP / Sep 2013
V P - 8
i P
P R O G U I
Stereo Enhancement
The
VP‑8
iP
is equipped with a flexible stereo enhancement
scheme allowing the air sound to be fully customized. There are two
sets of controls involved in the stereo enhancement algorithm; the
main Stereo Enhancement control and the five multiband AGC mix
controls for the L-R signal.
The main Stereo
Enhancement control adjusts the mix level
of the AGC’s L-R processing after the four
individual band mix controls. The individual
AGC L-R mix controls adjust the level prior
to the main Stereo Enhance control. Why
is this needed? At times it can be desirable
to modify how the L-R signal sounds to a
listener. For instance, female-oriented for-
mats might prefer a somewhat softer sound
in order to enhance long term listening so
being able to slightly reduce the L-R levels
from band 3 and 4 can make the sound more
“mellow.” The diagram on right shows the
basic signal flow of the stereo enhancer
algorithm.
AGC Enable/Comp. Enable Buttons
These buttons determine the presence of the AGC section and the Compressor section
in the output.
AGC Enable
– When illuminated by clicking on it, indicates that the
output of the AGC section is in the audio path.
Comp. Enable
– When illuminated by clicking on it, indicates that
the output of the Compressor section is in the audio path.
Compressor Out / AGC Out – When both AGC and Compressor are
switched off, signal is being bypassed around the Compressor and AGC
sections with no gain control being performed.
Compressor In / AGC Out – Signal is being routed through the
Compressor only, which operates with relatively fast time constants. The sound of the
processing will be quite obvious on most program material.
Compressor Out / AGC In – Signal is being routed through the AGC only, which
operates with relatively slow time constants. The sound of the processing will be quite
invisible on most program material but very short term variations in level will not be
corrected.
Compressor In / AGC In – Signal is being routed through the AGC and Compressor,
which together operate with different time constants. The sound of the processing will
be quite smooth with both short and long term variations in level being corrected (also
see AGC Backoff).