Orban OPTIMOD-FM 8500S Operating Manual page 235

OPTIMOD-FM DIGITAL
On 8500S PC Remote, there are buttons available on the button bar to toggle the
FM HD mode. When the FM HD mode is I
toggles between corresponding FM and HD tabs (for example, between
and HD C
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
EQ control in the I
S
HELF
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
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
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
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
Function
HF Shelving Filter
Look-Ahead Limiter
HD De-Esser
FM HD Control Coupling
Table 3-12: Unique HD Audio Controls (found in HD Distortion page in PC Remote)
).
OMPRESSORS
/ O HD D
NPUT UTPUT IGITAL
HD B
Control Name
HD EQ Gain
HD EQ Freq
HD Limiter Drive
HD De-Ess
FM HD Control
Coupling
, a button on the toolbar
NDEPENDENT
screen).
R
ADIO
M
controls are probably more
AND IX
AND
Values
0...–6 dB; 0.5 dB steps
2...– 20 kHz; 1/6-octave steps
0...+12 dB; 1.0 dB steps
Off, –23.5...0
FM HD; Independent
OPERATION
controls
M
IX
D
IMITER R
HD
3-71