Orban OPTIMOD-FM 8700, Operating Manual

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OPTIMOD-FM DIGITAL OPERATION
3-61
2B Clipping is a compression threshold control that affects the bass and master
bands equally. It sets the drive level to the high frequency limiting and multiband
distortion-controlling processing that precedes the final clipping section. The distor-
tion-controlling section uses a combination of distortion-cancelled clipping and
look-ahead processing to anticipate and prevent excessive clipping distortion in the
final clipper.
This control does not affect the HD processing chain.
MB Limit Threshold (not in MX presets) determines the threshold of the look-ahead
clipping distortion controller (measured in dB) with reference to the final clipper. In
general, it should be set at “0” so that it matches the threshold of the final clipper.
Setting it higher than “0” allows more punch (due to clipping) at the expense of
higher clipping distortion, which may be particularly annoying on voice.
This control does not affect the HD processing chain.
2B HF Limiting (not in MX presets) sets the threshold of the high frequency limiter in
the Two-Band structure. When this control is set lower, gain reduction does more
high frequency limiting. When this control is set higher, distortion-cancelled clipping
does more high frequency limiting. It controls the tradeoff between loss of high fre-
quencies (due to high frequency limiting) and excessive distortion (due to clipping).
This control only affects the analog processing chain.
The HF Limiting control is in the clippers screen in the unit.
HF Clip Threshold (not in MX presets) sets the threshold of the multiband, distortion-
cancelled clipper in the Two-Band structure’s high frequency limiter. Higher num-
bers yield more brightness, but also cause more high frequency distortion.
This control does not affect the HD processing chain.
Max DistCntr (Maximum Distortion Control ; not in MX presets). See Max Dist Ctrl;
page 3-71.
Speech Thresh (Speech Threshold) control. See MB Speech Threshold on page 3-73.
The Two-Band MX presets have the same peak limiting controls as the Five-Band MX
presets. See
8700i MX Technology Peak Limiter Controls starting on page 3-53.
The Five-Band Structure
The Five-Band structure consists of a stereo enhancer, a slow gain-riding two-band
AGC, an equalization section, a five-band compressor, a dynamic single-ended noise
reduction system, an output mixer (for the five bands), and a complex peak limiting
system. The peak limiting system depends on the preset name. Presets with “MX” in
their names invoke the 8700i’s MX limiter to achieve the highest performance avail-
able in the 8700i. MX presets offer greater transient impact, less preemphasis-
induced high frequency loss, and lower perceived distortion than their 8500-
technology counterparts. Achieving this level of performance requires the MX pre-
sets to have much longer delays (typically 265 milliseconds) than the 8500-style pre-