OPTIMOD-PC
OPERATION
3-31
considerable dynamic bass boost on voice. This setting might be appropriate for
news and sports.
The difference will never exceed the difference that would have other-
wise occurred if the lowest frequency band were gated independently. If
you are familiar with older Orban processors like OPTIMOD-FM 8200, this
is the maximum amount of boost that would have occurred if you had
set their
DJ
B
ASS
B
OOST
controls to
O
N
.
The amount of bass boost will be highly dependent on the fundamental
frequency of a given voice. If the fundamental frequency is far above
100Hz, there will be little voice energy in the bottom band and little or
no audio bass boost can occur even if the gain of the bottom band is
higher than the gain of its neighbor. As the fundamental frequency
moves lower, more of this energy leaks into the bottom band, and you
hear more bass boost. If the fundamental frequency is very low (a rarity),
there will be enough energy in the bottom band to force significant gain
reduction, and you will hear less bass boost than if the fundamental fre-
quency were a bit higher.
This control is only available in the Five-Band structure.
If the
G
ATE
T
HRESH
(Gate Threshold) control is turned
O
FF
, the
DJ
B
ASS
boost setting is disabled.
HF Enhance
is a program-adaptive, 6 dB/octave shelving equalizer with a 4 kHz
turnover frequency. It constantly monitors the ratio between high frequency and
broadband energy and adjusts the amount of equalization in an attempt to make
this ratio constant as the program material changes. It can therefore create a bright,
present sound without over-equalizing material that is already bright.
Highpass Filter
determines if a sweepable 18 dB/octave highpass filter will be
placed in-circuit before other processing. This filter is useful for reducing low fre-
quency noise, particularly when OPTIMOD-PC is being used for production or mas-
tering.
Lowpass Filter
control sets the bandwidth (and therefore the amount of high fre-
quency signal OPTIMOD-PC passes) from 10 kHz to 20 kHz. The lowpass filter can
replace any anti-aliasing filters in downstream equipment. Set the filter to 20 kHz
(full bandwidth) for downstream equipment with sample rates of 44.1 or 48 kHz. Set
the filter to 15 kHz for 32 kHz sample rate. For other sample rates, set the filter so
that it is as close as possible to 45% of the sample rate without exceeding 45%.
This setting is unique to the preset in which it resides. Regardless of its
setting, OPTIMOD-PC will not permit the system bandwidth to exceed the
bandwidth set by the
M
AX
L
OWPASS
F
ILTER
parameter located in the Con-
figuration page of the I/O Mixer.
Phase Rotator
determines if the phase rotator will be in-circuit. The purpose of the
phase rotator is to make voice waveforms more symmetrical. Because it can slightly
reduce the clarity and definition of program material, we recommend leaving it
O
UT
unless program material is mainly speech, where it may result in cleaner sound be-
cause it can substantially reduce the amount of gain reduction that OPTIMOD-PC’s
look-ahead limiter produces on speech waveforms.
