Orban Optimod-PC 1101, Operating Manual

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OPTIMOD-PC OPERATION
3-37
LF 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, 1.5 octaves is a good starting point. These curves are relatively
broad because they are designed to provide overall tonal coloration, ra-
ther than to notch out small areas of the spectrum.
The LF parametric can be used in the mid-bass region (100-300Hz) to add
“warmth” and “mellowness” to the sound when boosting. When cutting,
it can remove a “woody” or “boxy” sound.
The equalizer, like the classic Orban model 622B, has constant “Q”
curves. This means that the cut curves are narrower than the boost
curves. The width (in octaves) is calibrated with reference to 10 dB boost.
As you decrease the amount of EQ gain (or start to cut), the width in oc-
taves will decrease. However, the “Q” will stay constant.
“Q” is a mathematical parameter that relates to how fast ringing damps
out. (Technically, we are referring to the “Q” of the poles of the equal-
izer transfer function, which does not change as you adjust the amount
of boost or cut.)
The curves in OPTIMOD-PC’s equalizer were created by a so-called “min-
imax” (“minimize the maximum error” or “equal-ripple”) IIR digital ap-
proximation to the curves provided by the Orban 622B analog parametric
equalizer. Therefore, unlike less sophisticated digital equalizers that use
the “bilinear transformation” to generate EQ curves, the shapes of
OPTIMOD-PC’s curves are not distorted at high frequencies.
Equalizer Controls
Group Name Range
Bass Frequency 80, 85, 90, 95, 100, 105, 110, 115, 120, 125,
130, 135, 140, 145, 150, 160, 170, 180, 190,
200, 210, 220, 230, 240, 250, 270, 290, 310,
330, 350, 380, 410, 440, 470, 500Hz
Bass Gain 0 … 12 dB
Bass Shelf
Bass Slope 6,12,18 dB/Oct
Low Frequency 20 ... 500 Hz
Low Gain –10.0 … +10.0 dB
Low
Low Width 0.8 ... 4 octaves
Mid Frequency 250 ... 6000 Hz
Mid Gain –10.0 … +10.0 dB
Mid
Mid Width 0.8 ... 4 octaves
High Frequency 1.0 … 15.0 kHz
High Gain –10.0 … +10.0 dB
High
High Width 0.8 ... 4 octaves
HF Enhancer High Frequency En-
hancer 0 … 15
DJ Bass (5B) DJ Bass Boost Off, 1… +10 dB
Highpass Filter Highpass Filter Off, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110,
120, 130, 140, 150, 170, 200 Hz
Lowpass Filter Lowpass Filter 10, 11 ,12, 13, 14, 15, 20 kHz
Phase Rotate
Phase Rotate In / Out
Table 3-4: Equalizer Controls