Orban OPTIMOD-FM 8600, Руководство по эксплуатации

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OPTIMOD-FM DIGITAL OPERATION
3-33
The curves in the 8600’s equalizer were created by a so-called “minimax”
(Minimize the Maximum error, or “equal-ripple”) IIR digital approxima-
tion to the curves provided by the Orban 622B analog parametric equal-
izer. Therefore, unlike less sophisticated digital equalizers that use the
“bilinear transformation” to generate EQ curves, the shapes of the 8600’s
curves accurately emulate an analog equalizer, even at high frequencies.
Midrange Parametric Equalizer is a parametric equalizer whose boost and cut
curves closely emulate those of an analog parametric equalizer with conventional
bell-shaped curves.
Mid Frequency determines the center frequency of the equalization, in
Hertz. Range is 250-6000 Hz.
Mid Gain
determines the amount of peak boost or cut (in dB) over a
±
10
dB range.
Mid Width
determines the bandwidth of the equalization, in octaves.
The range is 0.8-4.0 octaves. If you are unfamiliar with using a parametric
equalizer, 1 octave is a good starting point.
The audible effect of the midrange equalizer is closely associated with
the amount of gain reduction in the midrange bands. With small
amounts of gain reduction, it boosts power in the presence region. This
can increase the loudness of such material substantially. As you increase
the gain reduction in the midrange bands (by turning the
MB D
RIVE
(Multiband Drive) control up), the
M
ID
G
AIN
control will have progressive-
ly less audible effect. The compressor for the midrange bands will tend to
reduce the effect of the Mid frequency boost (in an attempt to keep the
gain constant) to prevent excessive stridency in program material that al-
ready has a great deal of presence power. Therefore, with large amounts
of gain reduction, the density of presence region energy will be increased
more than will the level of energy in that region. Because the 3.7 kHz
band compressor is partially coupled to the gain reduction in the 6.2 kHz
band in most presets, tuning
M
ID
F
REQ
to 2-4 kHz and turning up the
M
ID
G
AIN
control will decrease energy in the 6.2 kHz band—you will be in-
creasing the gain reduction in both the 3.7 kHz and 6.2 kHz bands. You
may wish to compensate for this effect by turning up the
B
RILLIANCE
con-
trol.
Use the mid frequency equalizer with caution. Excessive presence boost
tends to be audibly strident and fatiguing. Moreover, the sound quality,
although loud, can be very irritating. We suggest a maximum of 3 dB
boost, although 10 dB is achievable. In some of our factory presets, we
use 3 dB boost at 2.6 kHz to bring vocals more up-front.
High Frequency Parametric Equalizer is a parametric equalizer whose boost and
cut curves closely emulate those of an analog parametric equalizer with convention-
al bell-shaped curves.
High Frequency determines the center frequency of the equalization, in
Hertz. The range is 1-15 kHz
High Gain determines the amount of peak boost or cut over a
±
10 dB
range.