Orban OPTIMOD 6200, Operating Manual

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OPTIMOD OPERATION
3-19
HF FREQ determines the center frequency of the equalization, in Hertz. The
range is 2-20kHz
HF WIDTH determines the bandwidth of the equalization, in octaves. The
range is 0.3-2.0 octaves. If you are unfamiliar with using a parametric equal-
izer, 1 octave is a good starting point.
Excessive high frequency boost can exaggerate tape hiss and distortion in
program material that is less than perfectly clean. We suggest no more than
4dB boost as a practical maximum, unless source material is primarily from
compact discs of recently recorded material.
LO PASS control sets the bandwidth (and therefore the amount of high frequency signal
the 6200 passes) from 4kHz to 20kHz. The lowpass filter can replace any anti-aliasing
filters in downstream equipment. Set the filter to 20kHz (full bandwidth) for downstream
equipment with sample rates of 44.1 or 48kHz. Set the filter to 15kHz for 32kHz 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%.
Multi-Band OUT Mix controls determine the relative balance of the bands in the multi-
band compressor. Because these controls mix after the band compressors, they do not
affect the compressors’ gain reductions and can be used as a graphic equalizer to fine-
tune the spectral balance of the program material over a
±
3dB range.
Their range has been purposely limited because the only gain control ele-
ment after these controls is the look-ahead limiter. Like a clipper, this circuit
can produce considerable intermodulation distortion if overdriven. The
thresholds of the individual compressors have been carefully tuned to pre-
vent audible IM distortion with almost any program material. Large changes
in the frequency balance of the compressor outputs will change this tuning,
leaving the 6200 more vulnerable to unexpected IM distortion with certain
program material. Therefore you should make large changes in EQ with the
bass and parametric equalizers, because these are located before the com-
pressors and the compressors will therefore protect the system from unusual
overloads caused by the chosen equalization. Use the multi-band
OUT mix
controls only for fine-tuning.