Orban Optimod-PC 1101, Руководство по эксплуатации

Страница: 166 / 258

3-46
OPERATION ORBAN MODEL 1101
peaks or dips around the crossover frequency. The two bands are down 3 dB at the
crossover frequency. However, this mode adds group delay distortion and is there-
fore subtly less transparent-sounding than the
L
INEAR
N
O
D
ELAY
mode.
L
INEAR
N
O
D
ELAY
(Linear-Phase; no delay) is a phase-linear crossover whose upper
band is derived by subtracting its lower band from the crossover’s input. When the
upper and lower bands have the same gain, their sum is perfectly flat with no phase
rotation. However, when the upper and lower bands have different gains, peaks
and dips appear in the frequency response close to the crossover frequency.
It is use-
ful if you need a crossover with low delay and no phase distortion when flat. Its
downside is the possibility of audible coloration when the gains of the two bands
are considerably unequal.
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 OPTIMOD-PC’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
AX
D
ELT
GR control greater than zero.
AGC Max Delta GR 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
modes, in both cases controlling the
maximum gain difference between the “channels.” Depending on the
M
ATRIX
mode setting, the “channels” will handle left and right signals or
will handle sum and difference signals. When the AGC operates in sum /
difference
M
ATRIX
mode, this control determines the maximum amount
of width change in the stereo soundfield.
Master Delta Threshold allows you to set the difference between the compression
thresholds of the sum and difference channels. (This control is only useful when you
set the
AGC M
ATRIX
to
SUM
/
DIF
.) By setting the threshold of the difference channel
lower than the sum channel, you can have the AGC automatically produce more
gain reduction in the difference channel. This will reduce the separation of material
with an excessively wide stereo image (like old Beatles records). To make this work,
you must set the
M
AX
D
ELTA
GR
control away from zero. For example, to limit an ex-
cessively wide image while preventing more than 3 dB difference in gain between
the sum and difference channels, set the
M
AX
D
ELTA
GR
control to 3.0 and the
M
ASTER
D
ELTA
T
HRESHOLD
control to some positive number, depending on how much
automatic width control you want OPTIMOD-PC to perform.
Bass Delta Threshold works the same as
M
ASTER
D
ELTA
T
HRESHOLD
,
but applies to
the bass band. You will usually set it the same as
M
ASTER
D
ELTA
T
HRESHOLD
.
Distortion Control
The distortion control adjustments are common to the Two-Band and Five-Band
structures except as noted in the descriptions on the following pages.