OPTIMOD-FM DIGITAL
OPERATION
3-71
On 8500S PC Remote, there are buttons available on the button bar to toggle the
FM
Æ
HD
mode. When the
FM
Æ
HD
mode is
I
NDEPENDENT
, a button on the toolbar
toggles between corresponding FM and HD tabs (for example, between
C
OMPRESSORS
and
HD
C
OMPRESSORS
).
HD EQ Gain
determines the depth of high frequency shelving equalization pro-
duced by the parametric HF shelving equalizer, which will be placed either before or
after the digital-channel look-ahead limiter (depending on the setting of the
HD
HF
S
HELF
EQ
control in the
I
NPUT
/
O
UTPUT
HD
D
IGITAL
R
ADIO
screen).
When placed before the look-ahead limiter, this equalizer is sometimes
useful for reducing the audible disparity between the FM and digital-
channel outputs (although the
HD
B
AND
M
IX
controls are probably more
appropriate for this task). The digital-channel output receives no high
frequency limiting or clipping and may therefore be as much as 6 dB
brighter than the FM output. If you wish to reduce this difference to
smooth out the audible difference between the two channels during a
receiver crossfade, you can apply HF rolloff to the digital-channel channel
by ear. Another reason you might want to do this is if the digital-channel
channel sounds excessively bright after you have optimized the 8500S’s
tuning for FM. Of course, you can also use the
HD
MB
B
AND
M
IX
controls
for this purpose, or use these controls in conjunction with the HF shelving
equalizer.
Yet another reason to use HF rolloff in the digital-channel channel is to
reduce codec artifacts at the high frequencies—the familiar “watery”
sound.
When placed after the look-ahead limiter, the shelving EQ can reduce
the effects of codec overshoot.
The parametric HF shelving equalizer can only produce HF rolloff. It can-
not boost.
HD EQ Freq
sets the corner frequency of the parametric HF shelving equalizer.
HD Limiter Dr
sets the drive level to the digital-channel look-ahead limiter.
•
When the BS.1770 Safety Limiter is active, you must use the
HD
L
IMITER
D
R
control to set the amount of gain reduction that the BS.1770 Safety Limiter
produces. See step 12 on page 2-35.
The factory default is
+4
. When the BS.1770 Safety Limiter is active, the
HD
Function
Control Name
Values
HF Shelving Filter
HD EQ Gain
0…–6 dB; 0.5 dB steps
HD EQ Freq
2…– 20 kHz; 1/6-octave steps
Look-Ahead Limiter
HD Limiter Drive
0…+12 dB; 1.0 dB steps
HD De-Esser
HD De-Ess
Off, –23.5…0
FM
Æ
HD Control Coupling
FM
Æ
HD Control
Coupling
FM
Æ
HD; Independent
Table 3-12: Unique HD Audio Controls (found in HD Distortion page in PC Remote)
Summary of Contents for OPTIMOD-FM 8500S
Page 1: ...Operating Manual OPTIMOD FM 8500S Digital Audio Processor Version 1 0 Software...
Page 7: ...Operating Manual OPTIMOD FM 8500S Digital Audio Processor Version 1 0 Software...
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Page 310: ...6 28 TECHNICAL DATA ORBAN MODEL 8500S CONTROL BOARD PARTS LOCATOR...
