About The 6300'S Signal Processing Features; Signal Flow - Orban OPTIMOD 6300 Operating Manual

3-8
OPERATION

About the 6300's Signal Processing Features

Signal Flow

rectly (so that it is cognizant of the D
viewers), its TVxxxx presets achieve this goal most precisely by exploiting the loud-
ness controller.
If you want more consistent loudness from a "radio-style" preset, set its
L C
OUDNESS
D
control until the loudness controller gain reduction meter indicates
RIVE
about 3 dB of gain reduction with typical program material, and save the
result as a user preset. Also, please refer to Setting Preset Loudness Cor-
rectly in Dolby Digital Transmission on page 3-17.
The signal flows through the 6300 through the following blocks (see page 6-43):

Input Conditioning, including sample rate conversion, defeatable highpass fil-
tering, and defeatable phase rotation

Stereo Enhancement

2-band Gated AGC, with target-zone window gating and silence gating

Equalization, including high-frequency enhancement

Multiband Compression in either two or five bands, depending on the proc-
essing structure

Automatic Loudness Control using Orban's third-generation CBS Loudness
Controller™ algorithm plus a BS.1770 Safety Limiter

Look-Ahead Limiting
A sample rate converter converts the sample rate at the digital input to the 6300's
internal 48 kHz rate. This 48 kHz rate accommodates a 20 kHz audio bandwidth with
a comfortably wide 4 kHz transition band for the anti-aliasing filter. We are aware
of no bias-controlled double-blind studies that have ever demonstrated that sample
rates higher than 48 kHz are audibly superior to 48 kHz (or even that there is any
audible difference at all). Moreover, the noise and distortion produced by a given
digital filter at 48 kHz is about 6 dB lower than the N&D produced by a filter having
the same frequency response but operating at 96 kHz. The 6300 uses many digital
filters, both in its equalizer section and for the crossovers in the multiband compres-
sor. Hence, we believe that 48 kHz is the ideal rate for the 6300's audio processing.
A sweepable 18 dB/octave highpass filter and a defeatable phase rotator complete
the input-conditioning block. The highpass filter is useful for production applica-
tions where it is necessary to remove low frequency rumble from a recording. The
phase rotator makes speech more symmetrical, reducing its peak-to-average ratio by
as much as 6 dB without adding nonlinear distortion. Hence, phase rotation can be
very useful for loudness processing of speech.
IALNORM
T control to –10 dB, turn up its MB L
ONTROLLER HRESH
ORBAN MODEL 6300
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