Advanced Agc Controls - Orban OPTIMOD-FM 5500 Operation Manual

3-30
OPERATION

Advanced AGC Controls

Although it is located in the Full Modify screen (to make it easy for a preset devel-
oper to switch meter modes), this control is not part of the active preset and its set-
ting is not saved in User Presets, unlike the other controls in the Full Modify screens.
The meter mode always reverts to M
The following AGC controls are available only in the 5500 PC Remote software.
AGC Maximum Delta Gain Reduction determines the maximum gain difference
permitted between the two channels of the AGC. Set it to "0" for perfect stereo
coupling.
This control works the same regardless of whether the AGC operates in left/right or
sum/difference
M
ATRIX
between the "channels." Depending on the
handle left and right signals or will handle sum and difference signals. When the
AGC operates in sum/difference
amount of width change in the stereo sound field.
AGC Window Size determines the size of the "target zone" window in the AGC. If
the input level falls within this target zone, the AGC release time is set to the num-
ber specified by the AGC W
the normal AGC release, and essentially freezes the AGC gain. This prevents the AGC
from building up density in material whose level is already well controlled. If the
level goes outside the window, then the AGC switches to the release rate specified
by AGC M
R
ASTER ELEASE
The normal setting for the AGC
AGC Window Release (see AGC W
AGC Matrix allows you to operate the AGC in left/right mode, or in sum/difference
mode. Usually you will operate in left/right mode. However, sum/difference mode
can give a type of stereo enhancement that is different from the enhancement
modes offered in the 5500's built-in stereo enhancer. This will only work if you allow
the two channels of the AGC to have different gains. To do this, set the AGC
M D G R
AXIMUM ELTA AIN EDUCTION
It is unwise to set this control beyond 3 dB. Multipath distortion could increase be-
cause the amount of L–R energy builds up excessively. We prefer using the 5500's
stereo enhancer because its built-in gating circuits prevent over-enhancement.
AGC Ratio determines the compression ratio of the AGC. The compression ratio is
the ratio between the change in input level and the resulting change in output
level, both measured in units of dB.
Previous Orban AGCs had compression ratios very close to :1, which produces the
most consistent and uniform sound. However, the 5500 compressor can reduce this
when the user leaves Full Modify.
ASTER
modes, in both cases controlling the maximum gain difference
mode, this control determines the maximum
M
ATRIX
control. This is usually much slower than
R
INDOW ELEASE
, so the AGC can still correct large gain variations quickly.
is 3 dB.
W S
INDOW IZE
S
INDOW IZE
control greater than zero.
mode setting, the "channels" will
M
ATRIX
above.)
ORBAN MODEL 5500