Orban OPTIMOD-FM 8600, Руководство по эксплуатации

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3-80
OPERATION ORBAN MODEL 8600
HD “loudness wars” will not only reduce quality but will also cause un-
balanced, obtrusive crossfades between the analog and digital channels
in the radio. To brand your station’s sound, you can choose the precise
coloration you want on the digital channel. You can still take advantage
of all of the artistic choices implicit in stereo enhancer, equalization, and
multiband compression / limiting settings. Yet you do not need to use ex-
cessive peak limiting, which can only reduce quality.
HD De-Ess allows you to mix an adjustable amount of the high frequency limiter
gain control signal into Band 5 of the HD processing only. This control allows you to
reduce the high frequency response of the HD processing channel in a program-
adaptive manner and is intended to reduce strong sibilance (“ess” sounds) that
might otherwise sound obtrusive. Higher (less negative) numbers give more de-
essing action but will also be more likely to reduce “sparkle” with music. If you no-
tice excessive sibilance, we recommend that you start by setting the control at –18.0
and fine-tune it to taste from there. Once you have set the
HD D
E
-E
SS
control to
your liking, save the resulting preset as a User Preset.
The default setting is
–18
, which provides a good compromise between
brightest sound (which would be accomplished by setting the control to
OFF
) and control of high frequency artifacts that low bitrate codecs in-
troduce.
Starting with V2.0 software, Band 5 in the HD processing chain has its
own gain control sidechain that is independent of the FM processing
chain. Therefore, you can activate the HD Band 5 compressor to either
complement or replace the control that the
HD DE-ESS
control provides.
HD Bass Clip Threshold sets the threshold of the HD processing chain’s hard bass
clipper (the only bass clipper mode available in the HD chain) with reference to the
threshold of the HD processing chain’s peak limiter. (See
Bass Clip Thresh on page 3-
47 ). There are two controls, one for music mode and one for speech mode.
HD Bass Clip Shape (See Hard Clip Shape on page 3-49.)
ITU-R Multiplex Power Controller
The ITU-R recommends that the power in the composite baseband signal (including
the pilot tone), integrated over any 60-second interval, not exceed the power in a
sinewave that modulates the FM carrier to
±
19 kHz (25.3% modulation). Many Eu-
ropean countries are now enforcing this recommendation. (See ITU-R 412 Compli-
ance on page 3-13 for more information.)
The BS.1770 Safety Limiter for the analog radio processing chain is located immedi-
ately before the MPX power controller. Normally, both are used simultaneously, but
when the target loudness is –23 LUFS, the BS.1770 Safety Limiter typically produces
enough gain reduction to cause the MPX Power Controller to produce no gain re-
duction. See step 13 on page 2-25 for instructions on setting up the BS.1770 Safety
Limiter.